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2025-04-20KVM: arm64: Tear down vGIC on failed vCPU creationWill Deacon
commit 250f25367b58d8c65a1b060a2dda037eea09a672 upstream. If kvm_arch_vcpu_create() fails to share the vCPU page with the hypervisor, we propagate the error back to the ioctl but leave the vGIC vCPU data initialised. Note only does this leak the corresponding memory when the vCPU is destroyed but it can also lead to use-after-free if the redistributor device handling tries to walk into the vCPU. Add the missing cleanup to kvm_arch_vcpu_create(), ensuring that the vGIC vCPU structures are destroyed on error. Cc: <stable@vger.kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250314133409.9123-1-will@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Eagerly switch ZCR_EL{1,2}Mark Rutland
[ Upstream commit 59419f10045bc955d2229819c7cf7a8b0b9c5b59 ] In non-protected KVM modes, while the guest FPSIMD/SVE/SME state is live on the CPU, the host's active SVE VL may differ from the guest's maximum SVE VL: * For VHE hosts, when a VM uses NV, ZCR_EL2 contains a value constrained by the guest hypervisor, which may be less than or equal to that guest's maximum VL. Note: in this case the value of ZCR_EL1 is immaterial due to E2H. * For nVHE/hVHE hosts, ZCR_EL1 contains a value written by the guest, which may be less than or greater than the guest's maximum VL. Note: in this case hyp code traps host SVE usage and lazily restores ZCR_EL2 to the host's maximum VL, which may be greater than the guest's maximum VL. This can be the case between exiting a guest and kvm_arch_vcpu_put_fp(). If a softirq is taken during this period and the softirq handler tries to use kernel-mode NEON, then the kernel will fail to save the guest's FPSIMD/SVE state, and will pend a SIGKILL for the current thread. This happens because kvm_arch_vcpu_ctxsync_fp() binds the guest's live FPSIMD/SVE state with the guest's maximum SVE VL, and fpsimd_save_user_state() verifies that the live SVE VL is as expected before attempting to save the register state: | if (WARN_ON(sve_get_vl() != vl)) { | force_signal_inject(SIGKILL, SI_KERNEL, 0, 0); | return; | } Fix this and make this a bit easier to reason about by always eagerly switching ZCR_EL{1,2} at hyp during guest<->host transitions. With this happening, there's no need to trap host SVE usage, and the nVHE/nVHE __deactivate_cptr_traps() logic can be simplified to enable host access to all present FPSIMD/SVE/SME features. In protected nVHE/hVHE modes, the host's state is always saved/restored by hyp, and the guest's state is saved prior to exit to the host, so from the host's PoV the guest never has live FPSIMD/SVE/SME state, and the host's ZCR_EL1 is never clobbered by hyp. Fixes: 8c8010d69c132273 ("KVM: arm64: Save/restore SVE state for nVHE") Fixes: 2e3cf82063a00ea0 ("KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Will Deacon <will@kernel.org> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-9-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Mark some header functions as inlineMark Rutland
[ Upstream commit f9dd00de1e53a47763dfad601635d18542c3836d ] The shared hyp switch header has a number of static functions which might not be used by all files that include the header, and when unused they will provoke compiler warnings, e.g. | In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8: | ./arch/arm64/kvm/hyp/include/hyp/switch.h:703:13: warning: 'kvm_hyp_handle_dabt_low' defined but not used [-Wunused-function] | 703 | static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code) | | ^~~~~~~~~~~~~~~~~~~~~~~ | ./arch/arm64/kvm/hyp/include/hyp/switch.h:682:13: warning: 'kvm_hyp_handle_cp15_32' defined but not used [-Wunused-function] | 682 | static bool kvm_hyp_handle_cp15_32(struct kvm_vcpu *vcpu, u64 *exit_code) | | ^~~~~~~~~~~~~~~~~~~~~~ | ./arch/arm64/kvm/hyp/include/hyp/switch.h:662:13: warning: 'kvm_hyp_handle_sysreg' defined but not used [-Wunused-function] | 662 | static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) | | ^~~~~~~~~~~~~~~~~~~~~ | ./arch/arm64/kvm/hyp/include/hyp/switch.h:458:13: warning: 'kvm_hyp_handle_fpsimd' defined but not used [-Wunused-function] | 458 | static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) | | ^~~~~~~~~~~~~~~~~~~~~ | ./arch/arm64/kvm/hyp/include/hyp/switch.h:329:13: warning: 'kvm_hyp_handle_mops' defined but not used [-Wunused-function] | 329 | static bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code) | | ^~~~~~~~~~~~~~~~~~~ Mark these functions as 'inline' to suppress this warning. This shouldn't result in any functional change. At the same time, avoid the use of __alias() in the header and alias kvm_hyp_handle_iabt_low() and kvm_hyp_handle_watchpt_low() to kvm_hyp_handle_memory_fault() using CPP, matching the style in the rest of the kernel. For consistency, kvm_hyp_handle_memory_fault() is also marked as 'inline'. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-8-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Refactor exit handlersMark Rutland
[ Upstream commit 9b66195063c5a145843547b1d692bd189be85287 ] The hyp exit handling logic is largely shared between VHE and nVHE/hVHE, with common logic in arch/arm64/kvm/hyp/include/hyp/switch.h. The code in the header depends on function definitions provided by arch/arm64/kvm/hyp/vhe/switch.c and arch/arm64/kvm/hyp/nvhe/switch.c when they include the header. This is an unusual header dependency, and prevents the use of arch/arm64/kvm/hyp/include/hyp/switch.h in other files as this would result in compiler warnings regarding missing definitions, e.g. | In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8: | ./arch/arm64/kvm/hyp/include/hyp/switch.h:733:31: warning: 'kvm_get_exit_handler_array' used but never defined | 733 | static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu); | | ^~~~~~~~~~~~~~~~~~~~~~~~~~ | ./arch/arm64/kvm/hyp/include/hyp/switch.h:735:13: warning: 'early_exit_filter' used but never defined | 735 | static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code); | | ^~~~~~~~~~~~~~~~~ Refactor the logic such that the header doesn't depend on anything from the C files. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-7-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Remove VHE host restore of CPACR_EL1.SMENMark Rutland
[ Upstream commit 407a99c4654e8ea65393f412c421a55cac539f5b ] When KVM is in VHE mode, the host kernel tries to save and restore the configuration of CPACR_EL1.SMEN (i.e. CPTR_EL2.SMEN when HCR_EL2.E2H=1) across kvm_arch_vcpu_load_fp() and kvm_arch_vcpu_put_fp(), since the configuration may be clobbered by hyp when running a vCPU. This logic has historically been broken, and is currently redundant. This logic was originally introduced in commit: 861262ab86270206 ("KVM: arm64: Handle SME host state when running guests") At the time, the VHE hyp code would reset CPTR_EL2.SMEN to 0b00 when returning to the host, trapping host access to SME state. Unfortunately, this was unsafe as the host could take a softirq before calling kvm_arch_vcpu_put_fp(), and if a softirq handler were to use kernel mode NEON the resulting attempt to save the live FPSIMD/SVE/SME state would result in a fatal trap. That issue was limited to VHE mode. For nVHE/hVHE modes, KVM always saved/restored the host kernel's CPACR_EL1 value, and configured CPTR_EL2.TSM to 0b0, ensuring that host usage of SME would not be trapped. The issue above was incidentally fixed by commit: 375110ab51dec5dc ("KVM: arm64: Fix resetting SME trap values on reset for (h)VHE") That commit changed the VHE hyp code to configure CPTR_EL2.SMEN to 0b01 when returning to the host, permitting host kernel usage of SME, avoiding the issue described above. At the time, this was not identified as a fix for commit 861262ab86270206. Now that the host eagerly saves and unbinds its own FPSIMD/SVE/SME state, there's no need to save/restore the state of the EL0 SME trap. The kernel can safely save/restore state without trapping, as described above, and will restore userspace state (including trap controls) before returning to userspace. Remove the redundant logic. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-5-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> [Update for rework of flags storage -- broonie] Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Remove VHE host restore of CPACR_EL1.ZENMark Rutland
[ Upstream commit 459f059be702056d91537b99a129994aa6ccdd35 ] When KVM is in VHE mode, the host kernel tries to save and restore the configuration of CPACR_EL1.ZEN (i.e. CPTR_EL2.ZEN when HCR_EL2.E2H=1) across kvm_arch_vcpu_load_fp() and kvm_arch_vcpu_put_fp(), since the configuration may be clobbered by hyp when running a vCPU. This logic is currently redundant. The VHE hyp code unconditionally configures CPTR_EL2.ZEN to 0b01 when returning to the host, permitting host kernel usage of SVE. Now that the host eagerly saves and unbinds its own FPSIMD/SVE/SME state, there's no need to save/restore the state of the EL0 SVE trap. The kernel can safely save/restore state without trapping, as described above, and will restore userspace state (including trap controls) before returning to userspace. Remove the redundant logic. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-4-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> [Rework for refactoring of where the flags are stored -- broonie] Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Remove host FPSIMD saving for non-protected KVMMark Rutland
[ Upstream commit 8eca7f6d5100b6997df4f532090bc3f7e0203bef ] Now that the host eagerly saves its own FPSIMD/SVE/SME state, non-protected KVM never needs to save the host FPSIMD/SVE/SME state, and the code to do this is never used. Protected KVM still needs to save/restore the host FPSIMD/SVE state to avoid leaking guest state to the host (and to avoid revealing to the host whether the guest used FPSIMD/SVE/SME), and that code needs to be retained. Remove the unused code and data structures. To avoid the need for a stub copy of kvm_hyp_save_fpsimd_host() in the VHE hyp code, the nVHE/hVHE version is moved into the shared switch header, where it is only invoked when KVM is in protected mode. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME stateMark Rutland
[ Upstream commit fbc7e61195e23f744814e78524b73b59faa54ab4 ] There are several problems with the way hyp code lazily saves the host's FPSIMD/SVE state, including: * Host SVE being discarded unexpectedly due to inconsistent configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to result in QEMU crashes where SVE is used by memmove(), as reported by Eric Auger: https://issues.redhat.com/browse/RHEL-68997 * Host SVE state is discarded *after* modification by ptrace, which was an unintentional ptrace ABI change introduced with lazy discarding of SVE state. * The host FPMR value can be discarded when running a non-protected VM, where FPMR support is not exposed to a VM, and that VM uses FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR before unbinding the host's FPSIMD/SVE/SME state, leaving a stale value in memory. Avoid these by eagerly saving and "flushing" the host's FPSIMD/SVE/SME state when loading a vCPU such that KVM does not need to save any of the host's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is removed and the necessary call to fpsimd_save_and_flush_cpu_state() is placed in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr' should not be used, they are set to NULL; all uses of these will be removed in subsequent patches. Historical problems go back at least as far as v5.17, e.g. erroneous assumptions about TIF_SVE being clear in commit: 8383741ab2e773a9 ("KVM: arm64: Get rid of host SVE tracking/saving") ... and so this eager save+flush probably needs to be backported to ALL stable trees. Fixes: 93ae6b01bafee8fa ("KVM: arm64: Discard any SVE state when entering KVM guests") Fixes: 8c845e2731041f0f ("arm64/sve: Leave SVE enabled on syscall if we don't context switch") Fixes: ef3be86021c3bdf3 ("KVM: arm64: Add save/restore support for FPMR") Reported-by: Eric Auger <eauger@redhat.com> Reported-by: Wilco Dijkstra <wilco.dijkstra@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Eric Auger <eric.auger@redhat.com> Acked-by: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Fuad Tabba <tabba@google.com> Cc: Jeremy Linton <jeremy.linton@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250210195226.1215254-2-mark.rutland@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org> [ Mark: Handle vcpu/host flag conflict ] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28KVM: arm64: Calculate cptr_el2 traps on activating trapsFuad Tabba
[ Upstream commit 2fd5b4b0e7b440602455b79977bfa64dea101e6c ] Similar to VHE, calculate the value of cptr_el2 from scratch on activate traps. This removes the need to store cptr_el2 in every vcpu structure. Moreover, some traps, such as whether the guest owns the fp registers, need to be set on every vcpu run. Reported-by: James Clark <james.clark@linaro.org> Fixes: 5294afdbf45a ("KVM: arm64: Exclude FP ownership from kvm_vcpu_arch") Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20241216105057.579031-13-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-07KVM: arm64: Ensure a VMID is allocated before programming VTTBR_EL2Oliver Upton
commit fa808ed4e199ed17d878eb75b110bda30dd52434 upstream. Vladimir reports that a race condition to attach a VMID to a stage-2 MMU sometimes results in a vCPU entering the guest with a VMID of 0: | CPU1 | CPU2 | | | | kvm_arch_vcpu_ioctl_run | | vcpu_load <= load VTTBR_EL2 | | kvm_vmid->id = 0 | | | kvm_arch_vcpu_ioctl_run | | vcpu_load <= load VTTBR_EL2 | | with kvm_vmid->id = 0| | kvm_arm_vmid_update <= allocates fresh | | kvm_vmid->id and | | reload VTTBR_EL2 | | | | | kvm_arm_vmid_update <= observes that kvm_vmid->id | | already allocated, | | skips reload VTTBR_EL2 Oh yeah, it's as bad as it looks. Remember that VHE loads the stage-2 MMU eagerly but a VMID only gets attached to the MMU later on in the KVM_RUN loop. Even in the "best case" where VTTBR_EL2 correctly gets reprogrammed before entering the EL1&0 regime, there is a period of time where hardware is configured with VMID 0. That's completely insane. So, rather than decorating the 'late' binding with another hack, just allocate the damn thing up front. Attaching a VMID from vcpu_load() is still rollover safe since (surprise!) it'll always get called after a vCPU was preempted. Excuse me while I go find a brown paper bag. Cc: stable@vger.kernel.org Fixes: 934bf871f011 ("KVM: arm64: Load the stage-2 MMU context in kvm_vcpu_load_vhe()") Reported-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250219220737.130842-1-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17KVM: arm64: timer: Always evaluate the need for a soft timerMarc Zyngier
commit b450dcce93bc2cf6d2bfaf5a0de88a94ebad8f89 upstream. When updating the interrupt state for an emulated timer, we return early and skip the setup of a soft timer that runs in parallel with the guest. While this is OK if we have set the interrupt pending, it is pretty wrong if the guest moved CVAL into the future. In that case, no timer is armed and the guest can wait for a very long time (it will take a full put/load cycle for the situation to resolve). This is specially visible with EDK2 running at EL2, but still using the EL1 virtual timer, which in that case is fully emulated. Any key-press takes ages to be captured, as there is no UART interrupt and EDK2 relies on polling from a timer... The fix is simply to drop the early return. If the timer interrupt is pending, we will still return early, and otherwise arm the soft timer. Fixes: 4d74ecfa6458b ("KVM: arm64: Don't arm a hrtimer for an already pending timer") Cc: stable@vger.kernel.org Tested-by: Dmytro Terletskyi <dmytro_terletskyi@epam.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20250204110050.150560-2-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17arm64/kvm: Configure HYP TCR.PS/DS based on host stage1Ard Biesheuvel
commit f0da16992aef7e246b2f3bba1492e3a52c38ca0e upstream. When the host stage1 is configured for LPA2, the value currently being programmed into TCR_EL2.T0SZ may be invalid unless LPA2 is configured at HYP as well. This means kvm_lpa2_is_enabled() is not the right condition to test when setting TCR_EL2.DS, as it will return false if LPA2 is only available for stage 1 but not for stage 2. Similary, programming TCR_EL2.PS based on a limited IPA range due to lack of stage2 LPA2 support could potentially result in problems. So use lpa2_is_enabled() instead, and set the PS field according to the host's IPS, which is capped at 48 bits if LPA2 support is absent or disabled. Whether or not we can make meaningful use of such a configuration is a different question. Cc: stable@vger.kernel.org Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241212081841.2168124-11-ardb+git@google.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27KVM: arm64: Do not allow ID_AA64MMFR0_EL1.ASIDbits to be overriddenMarc Zyngier
commit 03c7527e97f73081633d773f9f8c2373f9854b25 upstream. Catalin reports that a hypervisor lying to a guest about the size of the ASID field may result in unexpected issues: - if the underlying HW does only supports 8 bit ASIDs, the ASID field in a TLBI VAE1* operation is only 8 bits, and the HW will ignore the other 8 bits - if on the contrary the HW is 16 bit capable, the ASID field in the same TLBI operation is always 16 bits, irrespective of the value of TCR_ELx.AS. This could lead to missed invalidations if the guest was lead to assume that the HW had 8 bit ASIDs while they really are 16 bit wide. In order to avoid any potential disaster that would be hard to debug, prenent the migration between a host with 8 bit ASIDs to one with wider ASIDs (the converse was obviously always forbidden). This is also consistent with what we already do for VMIDs. If it becomes absolutely mandatory to support such a migration path in the future, we will have to trap and emulate all TLBIs, something that nobody should look forward to. Fixes: d5a32b60dc18 ("KVM: arm64: Allow userspace to change ID_AA64MMFR{0-2}_EL1") Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Oliver Upton <oliver.upton@linux.dev> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20241203190236.505759-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-19KVM: arm64: Disable MPAM visibility by default and ignore VMM writesJames Morse
commit 6685f5d572c22e1003e7c0d089afe1c64340ab1f upstream. commit 011e5f5bf529f ("arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register") exposed the MPAM field of AA64PFR0_EL1 to guests, but didn't add trap handling. A previous patch supplied the missing trap handling. Existing VMs that have the MPAM field of ID_AA64PFR0_EL1 set need to be migratable, but there is little point enabling the MPAM CPU interface on new VMs until there is something a guest can do with it. Clear the MPAM field from the guest's ID_AA64PFR0_EL1 and on hardware that supports MPAM, politely ignore the VMMs attempts to set this bit. Guests exposed to this bug have the sanitised value of the MPAM field, so only the correct value needs to be ignored. This means the field can continue to be used to block migration to incompatible hardware (between MPAM=1 and MPAM=5), and the VMM can't rely on the field being ignored. Signed-off-by: James Morse <james.morse@arm.com> Co-developed-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Joey Gouly <joey.gouly@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241030160317.2528209-7-joey.gouly@arm.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev> [maz: adapted to lack of ID_FILTERED()] Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: vgic-its: Clear DTE when MAPD unmaps a deviceKunkun Jiang
commit e9649129d33dca561305fc590a7c4ba8c3e5675a upstream. vgic_its_save_device_tables will traverse its->device_list to save DTE for each device. vgic_its_restore_device_tables will traverse each entry of device table and check if it is valid. Restore if valid. But when MAPD unmaps a device, it does not invalidate the corresponding DTE. In the scenario of continuous saves and restores, there may be a situation where a device's DTE is not saved but is restored. This is unreasonable and may cause restore to fail. This patch clears the corresponding DTE when MAPD unmaps a device. Cc: stable@vger.kernel.org Fixes: 57a9a117154c ("KVM: arm64: vgic-its: Device table save/restore") Co-developed-by: Shusen Li <lishusen2@huawei.com> Signed-off-by: Shusen Li <lishusen2@huawei.com> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com> [Jing: Update with entry write helper] Signed-off-by: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20241107214137.428439-5-jingzhangos@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: vgic-its: Add a data length check in vgic_its_save_*Jing Zhang
commit 7fe28d7e68f92cc3d0668b8f2fbdf5c303ac3022 upstream. In all the vgic_its_save_*() functinos, they do not check whether the data length is 8 bytes before calling vgic_write_guest_lock. This patch adds the check. To prevent the kernel from being blown up when the fault occurs, KVM_BUG_ON() is used. And the other BUG_ON()s are replaced together. Cc: stable@vger.kernel.org Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com> [Jing: Update with the new entry read/write helpers] Signed-off-by: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20241107214137.428439-4-jingzhangos@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: Get rid of userspace_irqchip_in_useRaghavendra Rao Ananta
commit 38d7aacca09230fdb98a34194fec2af597e8e20d upstream. Improper use of userspace_irqchip_in_use led to syzbot hitting the following WARN_ON() in kvm_timer_update_irq(): WARNING: CPU: 0 PID: 3281 at arch/arm64/kvm/arch_timer.c:459 kvm_timer_update_irq+0x21c/0x394 Call trace: kvm_timer_update_irq+0x21c/0x394 arch/arm64/kvm/arch_timer.c:459 kvm_timer_vcpu_reset+0x158/0x684 arch/arm64/kvm/arch_timer.c:968 kvm_reset_vcpu+0x3b4/0x560 arch/arm64/kvm/reset.c:264 kvm_vcpu_set_target arch/arm64/kvm/arm.c:1553 [inline] kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1573 [inline] kvm_arch_vcpu_ioctl+0x112c/0x1b3c arch/arm64/kvm/arm.c:1695 kvm_vcpu_ioctl+0x4ec/0xf74 virt/kvm/kvm_main.c:4658 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x108/0x184 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x78/0x1b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x1b0 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x50 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x14c arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 The following sequence led to the scenario: - Userspace creates a VM and a vCPU. - The vCPU is initialized with KVM_ARM_VCPU_PMU_V3 during KVM_ARM_VCPU_INIT. - Without any other setup, such as vGIC or vPMU, userspace issues KVM_RUN on the vCPU. Since the vPMU is requested, but not setup, kvm_arm_pmu_v3_enable() fails in kvm_arch_vcpu_run_pid_change(). As a result, KVM_RUN returns after enabling the timer, but before incrementing 'userspace_irqchip_in_use': kvm_arch_vcpu_run_pid_change() ret = kvm_arm_pmu_v3_enable() if (!vcpu->arch.pmu.created) return -EINVAL; if (ret) return ret; [...] if (!irqchip_in_kernel(kvm)) static_branch_inc(&userspace_irqchip_in_use); - Userspace ignores the error and issues KVM_ARM_VCPU_INIT again. Since the timer is already enabled, control moves through the following flow, ultimately hitting the WARN_ON(): kvm_timer_vcpu_reset() if (timer->enabled) kvm_timer_update_irq() if (!userspace_irqchip()) ret = kvm_vgic_inject_irq() ret = vgic_lazy_init() if (unlikely(!vgic_initialized(kvm))) if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2) return -EBUSY; WARN_ON(ret); Theoretically, since userspace_irqchip_in_use's functionality can be simply replaced by '!irqchip_in_kernel()', get rid of the static key to avoid the mismanagement, which also helps with the syzbot issue. Cc: <stable@vger.kernel.org> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: vgic-its: Clear ITE when DISCARD frees an ITEKunkun Jiang
commit 7602ffd1d5e8927fadd5187cb4aed2fdc9c47143 upstream. When DISCARD frees an ITE, it does not invalidate the corresponding ITE. In the scenario of continuous saves and restores, there may be a situation where an ITE is not saved but is restored. This is unreasonable and may cause restore to fail. This patch clears the corresponding ITE when DISCARD frees an ITE. Cc: stable@vger.kernel.org Fixes: eff484e0298d ("KVM: arm64: vgic-its: ITT save and restore") Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com> [Jing: Update with entry write helper] Signed-off-by: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20241107214137.428439-6-jingzhangos@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: Don't retire aborted MMIO instructionOliver Upton
commit e735a5da64420a86be370b216c269b5dd8e830e2 upstream. Returning an abort to the guest for an unsupported MMIO access is a documented feature of the KVM UAPI. Nevertheless, it's clear that this plumbing has seen limited testing, since userspace can trivially cause a WARN in the MMIO return: WARNING: CPU: 0 PID: 30558 at arch/arm64/include/asm/kvm_emulate.h:536 kvm_handle_mmio_return+0x46c/0x5c4 arch/arm64/include/asm/kvm_emulate.h:536 Call trace: kvm_handle_mmio_return+0x46c/0x5c4 arch/arm64/include/asm/kvm_emulate.h:536 kvm_arch_vcpu_ioctl_run+0x98/0x15b4 arch/arm64/kvm/arm.c:1133 kvm_vcpu_ioctl+0x75c/0xa78 virt/kvm/kvm_main.c:4487 __do_sys_ioctl fs/ioctl.c:51 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x1e0/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x38/0x68 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x90/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 The splat is complaining that KVM is advancing PC while an exception is pending, i.e. that KVM is retiring the MMIO instruction despite a pending synchronous external abort. Womp womp. Fix the glaring UAPI bug by skipping over all the MMIO emulation in case there is a pending synchronous exception. Note that while userspace is capable of pending an asynchronous exception (SError, IRQ, or FIQ), it is still safe to retire the MMIO instruction in this case as (1) they are by definition asynchronous, and (2) KVM relies on hardware support for pending/delivering these exceptions instead of the software state machine for advancing PC. Cc: stable@vger.kernel.org Fixes: da345174ceca ("KVM: arm/arm64: Allow user injection of external data aborts") Reported-by: Alexander Potapenko <glider@google.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241025203106.3529261-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow statusRaghavendra Rao Ananta
commit 54bbee190d42166209185d89070c58a343bf514b upstream. DDI0487K.a D13.3.1 describes the PMU overflow condition, which evaluates to true if any counter's global enable (PMCR_EL0.E), overflow flag (PMOVSSET_EL0[n]), and interrupt enable (PMINTENSET_EL1[n]) are all 1. Of note, this does not require a counter to be enabled (i.e. PMCNTENSET_EL0[n] = 1) to generate an overflow. Align kvm_pmu_overflow_status() with the reality of the architecture and stop using PMCNTENSET_EL0 as part of the overflow condition. The bug was discovered while running an SBSA PMU test [*], which only sets PMCR.E, PMOVSSET<0>, PMINTENSET<0>, and expects an overflow interrupt. Cc: stable@vger.kernel.org Fixes: 76d883c4e640 ("arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register") Link: https://github.com/ARM-software/sbsa-acs/blob/master/test_pool/pmu/operating_system/test_pmu001.c Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> [ oliver: massaged changelog ] Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241120005230.2335682-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05KVM: arm64: vgic-v3: Sanitise guest writes to GICR_INVLPIRMarc Zyngier
commit d561491ba927cb5634094ff311795e9d618e9b86 upstream. Make sure we filter out non-LPI invalidation when handling writes to GICR_INVLPIR. Fixes: 4645d11f4a553 ("KVM: arm64: vgic-v3: Implement MMIO-based LPI invalidation") Reported-by: Alexander Potapenko <glider@google.com> Tested-by: Alexander Potapenko <glider@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241117165757.247686-2-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-17KVM: arm64: Ensure vgic_ready() is ordered against MMIO registrationOliver Upton
kvm_vgic_map_resources() prematurely marks the distributor as 'ready', potentially allowing vCPUs to enter the guest before the distributor's MMIO registration has been made visible. Plug the race by marking the distributor as ready only after MMIO registration is completed. Rely on the implied ordering of synchronize_srcu() to ensure the MMIO registration is visible before vgic_dist::ready. This also means that writers to vgic_dist::ready are now serialized by the slots_lock, which was effectively the case already as all writers held the slots_lock in addition to the config_lock. Fixes: 59112e9c390b ("KVM: arm64: vgic: Fix a circular locking issue") Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241017001947.2707312-3-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-17KVM: arm64: vgic: Don't check for vgic_ready() when setting NR_IRQSOliver Upton
KVM commits to a particular sizing of SPIs when the vgic is initialized, which is before the point a vgic becomes ready. On top of that, KVM supplies a default amount of SPIs should userspace not explicitly configure this. As such, the check for vgic_ready() in the handling of KVM_DEV_ARM_VGIC_GRP_NR_IRQS is completely wrong, and testing if nr_spis is nonzero is sufficient for preventing userspace from playing games with us. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241017001947.2707312-2-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-17KVM: arm64: Fix shift-out-of-bounds bugIlkka Koskinen
Fix a shift-out-of-bounds bug reported by UBSAN when running VM with MTE enabled host kernel. UBSAN: shift-out-of-bounds in arch/arm64/kvm/sys_regs.c:1988:14 shift exponent 33 is too large for 32-bit type 'int' CPU: 26 UID: 0 PID: 7629 Comm: qemu-kvm Not tainted 6.12.0-rc2 #34 Hardware name: IEI NF5280R7/Mitchell MB, BIOS 00.00. 2024-10-12 09:28:54 10/14/2024 Call trace: dump_backtrace+0xa0/0x128 show_stack+0x20/0x38 dump_stack_lvl+0x74/0x90 dump_stack+0x18/0x28 __ubsan_handle_shift_out_of_bounds+0xf8/0x1e0 reset_clidr+0x10c/0x1c8 kvm_reset_sys_regs+0x50/0x1c8 kvm_reset_vcpu+0xec/0x2b0 __kvm_vcpu_set_target+0x84/0x158 kvm_vcpu_set_target+0x138/0x168 kvm_arch_vcpu_ioctl_vcpu_init+0x40/0x2b0 kvm_arch_vcpu_ioctl+0x28c/0x4b8 kvm_vcpu_ioctl+0x4bc/0x7a8 __arm64_sys_ioctl+0xb4/0x100 invoke_syscall+0x70/0x100 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x158 el0t_64_sync_handler+0x120/0x130 el0t_64_sync+0x194/0x198 Fixes: 7af0c2534f4c ("KVM: arm64: Normalize cache configuration") Cc: stable@vger.kernel.org Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20241017025701.67936-1-ilkka@os.amperecomputing.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-17KVM: arm64: Shave a few bytes from the EL2 idmap codeMarc Zyngier
Our idmap is becoming too big, to the point where it doesn't fit in a 4kB page anymore. There are some low-hanging fruits though, such as the el2_init_state horror that is expanded 3 times in the kernel. Let's at least limit ourselves to two copies, which makes the kernel link again. At some point, we'll have to have a better way of doing this. Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241009204903.GA3353168@thelio-3990X
2024-10-11KVM: arm64: Don't eagerly teardown the vgic on init errorMarc Zyngier
As there is very little ordering in the KVM API, userspace can instanciate a half-baked GIC (missing its memory map, for example) at almost any time. This means that, with the right timing, a thread running vcpu-0 can enter the kernel without a GIC configured and get a GIC created behind its back by another thread. Amusingly, it will pick up that GIC and start messing with the data structures without the GIC having been fully initialised. Similarly, a thread running vcpu-1 can enter the kernel, and try to init the GIC that was previously created. Since this GIC isn't properly configured (no memory map), it fails to correctly initialise. And that's the point where we decide to teardown the GIC, freeing all its resources. Behind vcpu-0's back. Things stop pretty abruptly, with a variety of symptoms. Clearly, this isn't good, we should be a bit more careful about this. It is obvious that this guest is not viable, as it is missing some important part of its configuration. So instead of trying to tear bits of it down, let's just mark it as *dead*. It means that any further interaction from userspace will result in -EIO. The memory will be released on the "normal" path, when userspace gives up. Cc: stable@vger.kernel.org Reported-by: Alexander Potapenko <glider@google.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241009183603.3221824-1-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: Expose S1PIE to guestsMark Brown
Prior to commit 70ed7238297f ("KVM: arm64: Sanitise ID_AA64MMFR3_EL1") we just exposed the santised view of ID_AA64MMFR3_EL1 to guests, meaning that they saw both TCRX and S1PIE if present on the host machine. That commit added VMM control over the contents of the register and exposed S1POE but removed S1PIE, meaning that the extension is no longer visible to guests. Reenable support for S1PIE with VMM control. Fixes: 70ed7238297f ("KVM: arm64: Sanitise ID_AA64MMFR3_EL1") Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20241005-kvm-arm64-fix-s1pie-v1-1-5901f02de749@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: nv: Clarify safety of allowing TLBI unmaps to rescheduleOliver Upton
There's been a decent amount of attention around unmaps of nested MMUs, and TLBI handling is no exception to this. Add a comment clarifying why it is safe to reschedule during a TLBI unmap, even without a reference on the MMU in progress. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241007233028.2236133-5-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: nv: Punt stage-2 recycling to a vCPU requestOliver Upton
Currently, when a nested MMU is repurposed for some other MMU context, KVM unmaps everything during vcpu_load() while holding the MMU lock for write. This is quite a performance bottleneck for large nested VMs, as all vCPU scheduling will spin until the unmap completes. Start punting the MMU cleanup to a vCPU request, where it is then possible to periodically release the MMU lock and CPU in the presence of contention. Ensure that no vCPU winds up using a stale MMU by tracking the pending unmap on the S2 MMU itself and requesting an unmap on every vCPU that finds it. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: nv: Do not block when unmapping stage-2 if disallowedOliver Upton
Right now the nested code allows unmap operations on a shadow stage-2 to block unconditionally. This is wrong in a couple places, such as a non-blocking MMU notifier or on the back of a sched_in() notifier as part of shadow MMU recycling. Carry through whether or not blocking is allowed to kvm_pgtable_stage2_unmap(). This 'fixes' an issue where stage-2 MMU reclaim would precipitate a stack overflow from a pile of kvm_sched_in() callbacks, all trying to recycle a stage-2 MMU. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: nv: Keep reference on stage-2 MMU when scheduled outOliver Upton
If a vCPU is scheduling out and not in WFI emulation, it is highly likely it will get scheduled again soon and reuse the MMU it had before. Dropping the MMU at vcpu_put() can have some unfortunate consequences, as the MMU could get reclaimed and used in a different context, forcing another 'cold start' on an otherwise active MMU. Avoid that altogether by keeping a reference on the MMU if the vCPU is scheduling out, ensuring that another vCPU cannot reclaim it while the current vCPU is away. Since there are more MMUs than vCPUs, this does not affect the guarantee that an unused MMU is available at any time. Furthermore, this makes the vcpu->arch.hw_mmu ~stable in preemptible code, at least for where it matters in the stage-2 abort path. Yes, the MMU can change across WFI emulation, but there isn't even a use case where this would matter. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241007233028.2236133-2-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08KVM: arm64: Unregister redistributor for failed vCPU creationOliver Upton
Alex reports that syzkaller has managed to trigger a use-after-free when tearing down a VM: BUG: KASAN: slab-use-after-free in kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769 Read of size 8 at addr ffffff801c6890d0 by task syz.3.2219/10758 CPU: 3 UID: 0 PID: 10758 Comm: syz.3.2219 Not tainted 6.11.0-rc6-dirty #64 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x17c/0x1a8 arch/arm64/kernel/stacktrace.c:317 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324 __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x94/0xc0 lib/dump_stack.c:119 print_report+0x144/0x7a4 mm/kasan/report.c:377 kasan_report+0xcc/0x128 mm/kasan/report.c:601 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 kvm_put_kvm+0x300/0xe68 virt/kvm/kvm_main.c:5769 kvm_vm_release+0x4c/0x60 virt/kvm/kvm_main.c:1409 __fput+0x198/0x71c fs/file_table.c:422 ____fput+0x20/0x30 fs/file_table.c:450 task_work_run+0x1cc/0x23c kernel/task_work.c:228 do_notify_resume+0x144/0x1a0 include/linux/resume_user_mode.h:50 el0_svc+0x64/0x68 arch/arm64/kernel/entry-common.c:169 el0t_64_sync_handler+0x90/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Upon closer inspection, it appears that we do not properly tear down the MMIO registration for a vCPU that fails creation late in the game, e.g. a vCPU w/ the same ID already exists in the VM. It is important to consider the context of commit that introduced this bug by moving the unregistration out of __kvm_vgic_vcpu_destroy(). That change correctly sought to avoid an srcu v. config_lock inversion by breaking up the vCPU teardown into two parts, one guarded by the config_lock. Fix the use-after-free while avoiding lock inversion by adding a special-cased unregistration to __kvm_vgic_vcpu_destroy(). This is safe because failed vCPUs are torn down outside of the config_lock. Cc: stable@vger.kernel.org Fixes: f616506754d3 ("KVM: arm64: vgic: Don't hold config_lock while unregistering redistributors") Reported-by: Alexander Potapenko <glider@google.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20241007223909.2157336-1-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08Merge branch kvm-arm64/idregs-6.12 into kvmarm/fixesMarc Zyngier
* kvm-arm64/idregs-6.12: : . : Make some fields of ID_AA64DFR0_EL1 and ID_AA64PFR1_EL1 : writable from userspace, so that a VMM can influence the : set of guest-visible features. : : - for ID_AA64DFR0_EL1: DoubleLock, WRPs, PMUVer and DebugVer : are writable (courtesy of Shameer Kolothum) : : - for ID_AA64PFR1_EL1: BT, SSBS, CVS2_frac are writable : (courtesy of Shaoqin Huang) : . KVM: selftests: aarch64: Add writable test for ID_AA64PFR1_EL1 KVM: arm64: Allow userspace to change ID_AA64PFR1_EL1 KVM: arm64: Use kvm_has_feat() to check if FEAT_SSBS is advertised to the guest KVM: arm64: Disable fields that KVM doesn't know how to handle in ID_AA64PFR1_EL1 KVM: arm64: Make the exposed feature bits in AA64DFR0_EL1 writable from userspace Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-01KVM: arm64: Constrain the host to the maximum shared SVE VL with pKVMMark Brown
When pKVM saves and restores the host floating point state on a SVE system, it programs the vector length in ZCR_EL2.LEN to be whatever the maximum VL for the PE is. But it uses a buffer allocated with kvm_host_sve_max_vl, the maximum VL shared by all PEs in the system. This means that if we run on a system where the maximum VLs are not consistent, we will overflow the buffer on PEs which support larger VLs. Since the host will not currently attempt to make use of non-shared VLs, fix this by explicitly setting the EL2 VL to be the maximum shared VL when we save and restore. This will enforce the limit on host VL usage. Should we wish to support asymmetric VLs, this code will need to be updated along with the required changes for the host: https://lore.kernel.org/r/20240730-kvm-arm64-fix-pkvm-sve-vl-v6-0-cae8a2e0bd66@kernel.org Fixes: b5b9955617bc ("KVM: arm64: Eagerly restore host fpsimd/sve state in pKVM") Signed-off-by: Mark Brown <broonie@kernel.org> Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240912-kvm-arm64-limit-guest-vl-v2-1-dd2c29cb2ac9@kernel.org [maz: added punctuation to the commit message] Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-01KVM: arm64: Fix __pkvm_init_vcpu cptr_el2 error pathVincent Donnefort
On an error, hyp_vcpu will be accessed while this memory has already been relinquished to the host and unmapped from the hypervisor. Protect the CPTR assignment with an early return. Fixes: b5b9955617bc ("KVM: arm64: Eagerly restore host fpsimd/sve state in pKVM") Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Link: https://lore.kernel.org/r/20240919110500.2345927-1-vdonnefort@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-28Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull x86 kvm updates from Paolo Bonzini: "x86: - KVM currently invalidates the entirety of the page tables, not just those for the memslot being touched, when a memslot is moved or deleted. This does not traditionally have particularly noticeable overhead, but Intel's TDX will require the guest to re-accept private pages if they are dropped from the secure EPT, which is a non starter. Actually, the only reason why this is not already being done is a bug which was never fully investigated and caused VM instability with assigned GeForce GPUs, so allow userspace to opt into the new behavior. - Advertise AVX10.1 to userspace (effectively prep work for the "real" AVX10 functionality that is on the horizon) - Rework common MSR handling code to suppress errors on userspace accesses to unsupported-but-advertised MSRs This will allow removing (almost?) all of KVM's exemptions for userspace access to MSRs that shouldn't exist based on the vCPU model (the actual cleanup is non-trivial future work) - Rework KVM's handling of x2APIC ICR, again, because AMD (x2AVIC) splits the 64-bit value into the legacy ICR and ICR2 storage, whereas Intel (APICv) stores the entire 64-bit value at the ICR offset - Fix a bug where KVM would fail to exit to userspace if one was triggered by a fastpath exit handler - Add fastpath handling of HLT VM-Exit to expedite re-entering the guest when there's already a pending wake event at the time of the exit - Fix a WARN caused by RSM entering a nested guest from SMM with invalid guest state, by forcing the vCPU out of guest mode prior to signalling SHUTDOWN (the SHUTDOWN hits the VM altogether, not the nested guest) - Overhaul the "unprotect and retry" logic to more precisely identify cases where retrying is actually helpful, and to harden all retry paths against putting the guest into an infinite retry loop - Add support for yielding, e.g. to honor NEED_RESCHED, when zapping rmaps in the shadow MMU - Refactor pieces of the shadow MMU related to aging SPTEs in prepartion for adding multi generation LRU support in KVM - Don't stuff the RSB after VM-Exit when RETPOLINE=y and AutoIBRS is enabled, i.e. when the CPU has already flushed the RSB - Trace the per-CPU host save area as a VMCB pointer to improve readability and cleanup the retrieval of the SEV-ES host save area - Remove unnecessary accounting of temporary nested VMCB related allocations - Set FINAL/PAGE in the page fault error code for EPT violations if and only if the GVA is valid. If the GVA is NOT valid, there is no guest-side page table walk and so stuffing paging related metadata is nonsensical - Fix a bug where KVM would incorrectly synthesize a nested VM-Exit instead of emulating posted interrupt delivery to L2 - Add a lockdep assertion to detect unsafe accesses of vmcs12 structures - Harden eVMCS loading against an impossible NULL pointer deref (really truly should be impossible) - Minor SGX fix and a cleanup - Misc cleanups Generic: - Register KVM's cpuhp and syscore callbacks when enabling virtualization in hardware, as the sole purpose of said callbacks is to disable and re-enable virtualization as needed - Enable virtualization when KVM is loaded, not right before the first VM is created Together with the previous change, this simplifies a lot the logic of the callbacks, because their very existence implies virtualization is enabled - Fix a bug that results in KVM prematurely exiting to userspace for coalesced MMIO/PIO in many cases, clean up the related code, and add a testcase - Fix a bug in kvm_clear_guest() where it would trigger a buffer overflow _if_ the gpa+len crosses a page boundary, which thankfully is guaranteed to not happen in the current code base. Add WARNs in more helpers that read/write guest memory to detect similar bugs Selftests: - Fix a goof that caused some Hyper-V tests to be skipped when run on bare metal, i.e. NOT in a VM - Add a regression test for KVM's handling of SHUTDOWN for an SEV-ES guest - Explicitly include one-off assets in .gitignore. Past Sean was completely wrong about not being able to detect missing .gitignore entries - Verify userspace single-stepping works when KVM happens to handle a VM-Exit in its fastpath - Misc cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (127 commits) Documentation: KVM: fix warning in "make htmldocs" s390: Enable KVM_S390_UCONTROL config in debug_defconfig selftests: kvm: s390: Add VM run test case KVM: SVM: let alternatives handle the cases when RSB filling is required KVM: VMX: Set PFERR_GUEST_{FINAL,PAGE}_MASK if and only if the GVA is valid KVM: x86/mmu: Use KVM_PAGES_PER_HPAGE() instead of an open coded equivalent KVM: x86/mmu: Add KVM_RMAP_MANY to replace open coded '1' and '1ul' literals KVM: x86/mmu: Fold mmu_spte_age() into kvm_rmap_age_gfn_range() KVM: x86/mmu: Morph kvm_handle_gfn_range() into an aging specific helper KVM: x86/mmu: Honor NEED_RESCHED when zapping rmaps and blocking is allowed KVM: x86/mmu: Add a helper to walk and zap rmaps for a memslot KVM: x86/mmu: Plumb a @can_yield parameter into __walk_slot_rmaps() KVM: x86/mmu: Move walk_slot_rmaps() up near for_each_slot_rmap_range() KVM: x86/mmu: WARN on MMIO cache hit when emulating write-protected gfn KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list KVM: x86/mmu: Subsume kvm_mmu_unprotect_page() into the and_retry() version KVM: x86: Rename reexecute_instruction()=>kvm_unprotect_and_retry_on_failure() KVM: x86: Update retry protection fields when forcing retry on emulation failure KVM: x86: Apply retry protection to "unprotect on failure" path KVM: x86: Check EMULTYPE_WRITE_PF_TO_SP before unprotecting gfn ...
2024-09-21Merge tag 'mm-stable-2024-09-20-02-31' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Along with the usual shower of singleton patches, notable patch series in this pull request are: - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds consistency to the APIs and behaviour of these two core allocation functions. This also simplifies/enables Rustification. - "Some cleanups for shmem" from Baolin Wang. No functional changes - mode code reuse, better function naming, logic simplifications. - "mm: some small page fault cleanups" from Josef Bacik. No functional changes - code cleanups only. - "Various memory tiering fixes" from Zi Yan. A small fix and a little cleanup. - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and simplifications and .text shrinkage. - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This is a feature, it adds new feilds to /proc/vmstat such as $ grep kstack /proc/vmstat kstack_1k 3 kstack_2k 188 kstack_4k 11391 kstack_8k 243 kstack_16k 0 which tells us that 11391 processes used 4k of stack while none at all used 16k. Useful for some system tuning things, but partivularly useful for "the dynamic kernel stack project". - "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory. - "mm: memcg: page counters optimizations" from Roman Gushchin. "3 independent small optimizations of page counters". - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work correctly by design rather than by accident. - "mm: remove arch_make_page_accessible()" from David Hildenbrand. Some folio conversions which make arch_make_page_accessible() unneeded. - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel. Cleans up and fixes our handling of the resetting of the cgroup/process peak-memory-use detector. - "Make core VMA operations internal and testable" from Lorenzo Stoakes. Rationalizaion and encapsulation of the VMA manipulation APIs. With a view to better enable testing of the VMA functions, even from a userspace-only harness. - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in the zswap global shrinker, resulting in improved performance. - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in some missing info in /proc/zoneinfo. - "mm: replace follow_page() by folio_walk" from David Hildenbrand. Code cleanups and rationalizations (conversion to folio_walk()) resulting in the removal of follow_page(). - "improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some tuning to improve zswap's dynamic shrinker. Significant reductions in swapin and improvements in performance are shown. - "mm: Fix several issues with unaccepted memory" from Kirill Shutemov. Improvements to the new unaccepted memory feature, - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX PUDs. This was missing, although nobody seems to have notied yet. - "Introduce a store type enum for the Maple tree" from Sidhartha Kumar. Cleanups and modest performance improvements for the maple tree library code. - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move more cgroup v1 remnants away from the v2 memcg code. - "memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds various warnings telling users that memcg v1 features are deprecated. - "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li. Greatly improves the success rate of the mTHP swap allocation. - "mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate per-arch implementations of numa_memblk code into generic code. - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly improves the performance of munmap() of swap-filled ptes. - "support large folio swap-out and swap-in for shmem" from Baolin Wang. With this series we no longer split shmem large folios into simgle-page folios when swapping out shmem. - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance improvements and code reductions for gigantic folios. - "support shmem mTHP collapse" from Baolin Wang. Adds support for khugepaged's collapsing of shmem mTHP folios. - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect() performance regression due to the addition of mseal(). - "Increase the number of bits available in page_type" from Matthew Wilcox. Increases the number of bits available in page_type! - "Simplify the page flags a little" from Matthew Wilcox. Many legacy page flags are now folio flags, so the page-based flags and their accessors/mutators can be removed. - "mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An optimization which permits us to avoid writing/reading zero-filled zswap pages to backing store. - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window which occurs when a MAP_FIXED operqtion is occurring during an unrelated vma tree walk. - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the vma_merge() functionality, making ot cleaner, more testable and better tested. - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor fixups of DAMON selftests and kunit tests. - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code cleanups and folio conversions. - "Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups for shmem controls and stats. - "mm: count the number of anonymous THPs per size" from Barry Song. Expose additional anon THP stats to userspace for improved tuning. - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio conversions and removal of now-unused page-based APIs. - "replace per-quota region priorities histogram buffer with per-context one" from SeongJae Park. DAMON histogram rationalization. - "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae Park. DAMON documentation updates. - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve related doc and warn" from Jason Wang: fixes usage of page allocator __GFP_NOFAIL and GFP_ATOMIC flags. - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy. This was overprovisioning THPs in sparsely accessed memory areas. - "zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add support for zram run-time compression algorithm tuning. - "mm: Care about shadow stack guard gap when getting an unmapped area" from Mark Brown. Fix up the various arch_get_unmapped_area() implementations to better respect guard areas. - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of mem_cgroup_iter() and various code cleanups. - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge pfnmap support. - "resource: Fix region_intersects() vs add_memory_driver_managed()" from Huang Ying. Fix a bug in region_intersects() for systems with CXL memory. - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a couple more code paths to correctly recover from the encountering of poisoned memry. - "mm: enable large folios swap-in support" from Barry Song. Support the swapin of mTHP memory into appropriately-sized folios, rather than into single-page folios" * tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits) zram: free secondary algorithms names uprobes: turn xol_area->pages[2] into xol_area->page uprobes: introduce the global struct vm_special_mapping xol_mapping Revert "uprobes: use vm_special_mapping close() functionality" mm: support large folios swap-in for sync io devices mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios mm: fix swap_read_folio_zeromap() for large folios with partial zeromap mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries set_memory: add __must_check to generic stubs mm/vma: return the exact errno in vms_gather_munmap_vmas() memcg: cleanup with !CONFIG_MEMCG_V1 mm/show_mem.c: report alloc tags in human readable units mm: support poison recovery from copy_present_page() mm: support poison recovery from do_cow_fault() resource, kunit: add test case for region_intersects() resource: make alloc_free_mem_region() works for iomem_resource mm: z3fold: deprecate CONFIG_Z3FOLD vfio/pci: implement huge_fault support mm/arm64: support large pfn mappings mm/x86: support large pfn mappings ...
2024-09-17Merge branch 'kvm-redo-enable-virt' into HEADPaolo Bonzini
Register KVM's cpuhp and syscore callbacks when enabling virtualization in hardware, as the sole purpose of said callbacks is to disable and re-enable virtualization as needed. The primary motivation for this series is to simplify dealing with enabling virtualization for Intel's TDX, which needs to enable virtualization when kvm-intel.ko is loaded, i.e. long before the first VM is created. That said, this is a nice cleanup on its own. By registering the callbacks on-demand, the callbacks themselves don't need to check kvm_usage_count, because their very existence implies a non-zero count. Patch 1 (re)adds a dedicated lock for kvm_usage_count. This avoids a lock ordering issue between cpus_read_lock() and kvm_lock. The lock ordering issue still exist in very rare cases, and will be fixed for good by switching vm_list to an (S)RCU-protected list. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-09-16Merge tag 'for-linus-non-x86' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "These are the non-x86 changes (mostly ARM, as is usually the case). The generic and x86 changes will come later" ARM: - New Stage-2 page table dumper, reusing the main ptdump infrastructure - FP8 support - Nested virtualization now supports the address translation (FEAT_ATS1A) family of instructions - Add selftest checks for a bunch of timer emulation corner cases - Fix multiple cases where KVM/arm64 doesn't correctly handle the guest trying to use a GICv3 that wasn't advertised - Remove REG_HIDDEN_USER from the sysreg infrastructure, making things little simpler - Prevent MTE tags being restored by userspace if we are actively logging writes, as that's a recipe for disaster - Correct the refcount on a page that is not considered for MTE tag copying (such as a device) - When walking a page table to split block mappings, synchronize only at the end the walk rather than on every store - Fix boundary check when transfering memory using FFA - Fix pKVM TLB invalidation, only affecting currently out of tree code but worth addressing for peace of mind LoongArch: - Revert qspinlock to test-and-set simple lock on VM. - Add Loongson Binary Translation extension support. - Add PMU support for guest. - Enable paravirt feature control from VMM. - Implement function kvm_para_has_feature(). RISC-V: - Fix sbiret init before forwarding to userspace - Don't zero-out PMU snapshot area before freeing data - Allow legacy PMU access from guest - Fix to allow hpmcounter31 from the guest" * tag 'for-linus-non-x86' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (64 commits) LoongArch: KVM: Implement function kvm_para_has_feature() LoongArch: KVM: Enable paravirt feature control from VMM LoongArch: KVM: Add PMU support for guest KVM: arm64: Get rid of REG_HIDDEN_USER visibility qualifier KVM: arm64: Simplify visibility handling of AArch32 SPSR_* KVM: arm64: Simplify handling of CNTKCTL_EL12 LoongArch: KVM: Add vm migration support for LBT registers LoongArch: KVM: Add Binary Translation extension support LoongArch: KVM: Add VM feature detection function LoongArch: Revert qspinlock to test-and-set simple lock on VM KVM: arm64: Register ptdump with debugfs on guest creation arm64: ptdump: Don't override the level when operating on the stage-2 tables arm64: ptdump: Use the ptdump description from a local context arm64: ptdump: Expose the attribute parsing functionality KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer KVM: arm64: Move pagetable definitions to common header KVM: arm64: nv: Add support for FEAT_ATS1A KVM: arm64: nv: Plumb handling of AT S1* traps from EL2 KVM: arm64: nv: Make AT+PAN instructions aware of FEAT_PAN3 KVM: arm64: nv: Sanitise SCTLR_EL1.EPAN according to VM configuration ...
2024-09-16Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "The highlights are support for Arm's "Permission Overlay Extension" using memory protection keys, support for running as a protected guest on Android as well as perf support for a bunch of new interconnect PMUs. Summary: ACPI: - Enable PMCG erratum workaround for HiSilicon HIP10 and 11 platforms. - Ensure arm64-specific IORT header is covered by MAINTAINERS. CPU Errata: - Enable workaround for hardware access/dirty issue on Ampere-1A cores. Memory management: - Define PHYSMEM_END to fix a crash in the amdgpu driver. - Avoid tripping over invalid kernel mappings on the kexec() path. - Userspace support for the Permission Overlay Extension (POE) using protection keys. Perf and PMUs: - Add support for the "fixed instruction counter" extension in the CPU PMU architecture. - Extend and fix the event encodings for Apple's M1 CPU PMU. - Allow LSM hooks to decide on SPE permissions for physical profiling. - Add support for the CMN S3 and NI-700 PMUs. Confidential Computing: - Add support for booting an arm64 kernel as a protected guest under Android's "Protected KVM" (pKVM) hypervisor. Selftests: - Fix vector length issues in the SVE/SME sigreturn tests - Fix build warning in the ptrace tests. Timers: - Add support for PR_{G,S}ET_TSC so that 'rr' can deal with non-determinism arising from the architected counter. Miscellaneous: - Rework our IPI-based CPU stopping code to try NMIs if regular IPIs don't succeed. - Minor fixes and cleanups" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (94 commits) perf: arm-ni: Fix an NULL vs IS_ERR() bug arm64: hibernate: Fix warning for cast from restricted gfp_t arm64: esr: Define ESR_ELx_EC_* constants as UL arm64: pkeys: remove redundant WARN perf: arm_pmuv3: Use BR_RETIRED for HW branch event if enabled MAINTAINERS: List Arm interconnect PMUs as supported perf: Add driver for Arm NI-700 interconnect PMU dt-bindings/perf: Add Arm NI-700 PMU perf/arm-cmn: Improve format attr printing perf/arm-cmn: Clean up unnecessary NUMA_NO_NODE check arm64/mm: use lm_alias() with addresses passed to memblock_free() mm: arm64: document why pte is not advanced in contpte_ptep_set_access_flags() arm64: Expose the end of the linear map in PHYSMEM_END arm64: trans_pgd: mark PTEs entries as valid to avoid dead kexec() arm64/mm: Delete __init region from memblock.reserved perf/arm-cmn: Support CMN S3 dt-bindings: perf: arm-cmn: Add CMN S3 perf/arm-cmn: Refactor DTC PMU register access perf/arm-cmn: Make cycle counts less surprising perf/arm-cmn: Improve build-time assertion ...
2024-09-12Merge branch 'for-next/poe' into for-next/coreWill Deacon
* for-next/poe: (31 commits) arm64: pkeys: remove redundant WARN kselftest/arm64: Add test case for POR_EL0 signal frame records kselftest/arm64: parse POE_MAGIC in a signal frame kselftest/arm64: add HWCAP test for FEAT_S1POE selftests: mm: make protection_keys test work on arm64 selftests: mm: move fpregs printing kselftest/arm64: move get_header() arm64: add Permission Overlay Extension Kconfig arm64: enable PKEY support for CPUs with S1POE arm64: enable POE and PIE to coexist arm64/ptrace: add support for FEAT_POE arm64: add POE signal support arm64: implement PKEYS support arm64: add pte_access_permitted_no_overlay() arm64: handle PKEY/POE faults arm64: mask out POIndex when modifying a PTE arm64: convert protection key into vm_flags and pgprot values arm64: add POIndex defines arm64: re-order MTE VM_ flags arm64: enable the Permission Overlay Extension for EL0 ...
2024-09-12Merge branch kvm-arm64/visibility-cleanups into kvmarm-master/nextMarc Zyngier
* kvm-arm64/visibility-cleanups: : . : Remove REG_HIDDEN_USER from the sysreg infrastructure, making things : a little more simple. From the cover letter: : : "Since 4d4f52052ba8 ("KVM: arm64: nv: Drop EL12 register traps that are : redirected to VNCR") and the admission that KVM would never be supporting : the original FEAT_NV, REG_HIDDEN_USER only had a few users, all of which : could either be replaced by a more ad-hoc mechanism, or removed altogether." : . KVM: arm64: Get rid of REG_HIDDEN_USER visibility qualifier KVM: arm64: Simplify visibility handling of AArch32 SPSR_* KVM: arm64: Simplify handling of CNTKCTL_EL12 Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-12Merge branch kvm-arm64/s2-ptdump into kvmarm-master/nextMarc Zyngier
* kvm-arm64/s2-ptdump: : . : Stage-2 page table dumper, reusing the main ptdump infrastructure, : courtesy of Sebastian Ene. From the cover letter: : : "This series extends the ptdump support to allow dumping the guest : stage-2 pagetables. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump : registers the new following files under debugfs: : - /sys/debug/kvm/<guest_id>/stage2_page_tables : - /sys/debug/kvm/<guest_id>/stage2_levels : - /sys/debug/kvm/<guest_id>/ipa_range : : This allows userspace tools (eg. cat) to dump the stage-2 pagetables by : reading the 'stage2_page_tables' file. : [...]" : . KVM: arm64: Register ptdump with debugfs on guest creation arm64: ptdump: Don't override the level when operating on the stage-2 tables arm64: ptdump: Use the ptdump description from a local context arm64: ptdump: Expose the attribute parsing functionality KVM: arm64: Move pagetable definitions to common header Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-12Merge branch kvm-arm64/nv-at-pan into kvmarm-master/nextMarc Zyngier
* kvm-arm64/nv-at-pan: : . : Add NV support for the AT family of instructions, which mostly results : in adding a page table walker that deals with most of the complexity : of the architecture. : : From the cover letter: : : "Another task that a hypervisor supporting NV on arm64 has to deal with : is to emulate the AT instruction, because we multiplex all the S1 : translations on a single set of registers, and the guest S2 is never : truly resident on the CPU. : : So given that we lie about page tables, we also have to lie about : translation instructions, hence the emulation. Things are made : complicated by the fact that guest S1 page tables can be swapped out, : and that our shadow S2 is likely to be incomplete. So while using AT : to emulate AT is tempting (and useful), it is not going to always : work, and we thus need a fallback in the shape of a SW S1 walker." : . KVM: arm64: nv: Add support for FEAT_ATS1A KVM: arm64: nv: Plumb handling of AT S1* traps from EL2 KVM: arm64: nv: Make AT+PAN instructions aware of FEAT_PAN3 KVM: arm64: nv: Sanitise SCTLR_EL1.EPAN according to VM configuration KVM: arm64: nv: Add SW walker for AT S1 emulation KVM: arm64: nv: Make ps_to_output_size() generally available KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W} KVM: arm64: nv: Add basic emulation of AT S1E2{R,W} KVM: arm64: nv: Add basic emulation of AT S1E1{R,W}P KVM: arm64: nv: Add basic emulation of AT S1E{0,1}{R,W} KVM: arm64: nv: Honor absence of FEAT_PAN2 KVM: arm64: nv: Turn upper_attr for S2 walk into the full descriptor KVM: arm64: nv: Enforce S2 alignment when contiguous bit is set arm64: Add ESR_ELx_FSC_ADDRSZ_L() helper arm64: Add system register encoding for PSTATE.PAN arm64: Add PAR_EL1 field description arm64: Add missing APTable and TCR_ELx.HPD masks KVM: arm64: Make kvm_at() take an OP_AT_* Signed-off-by: Marc Zyngier <maz@kernel.org> # Conflicts: # arch/arm64/kvm/nested.c
2024-09-12Merge branch kvm-arm64/vgic-sre-traps into kvmarm-master/nextMarc Zyngier
* kvm-arm64/vgic-sre-traps: : . : Fix the multiple of cases where KVM/arm64 doesn't correctly : handle the guest trying to use a GICv3 that isn't advertised. : : From the cover letter: : : "It recently appeared that, when running on a GICv3-equipped platform : (which is what non-ancient arm64 HW has), *not* configuring a GICv3 : for the guest could result in less than desirable outcomes. : : We have multiple issues to fix: : : - for registers that *always* trap (the SGI registers) or that *may* : trap (the SRE register), we need to check whether a GICv3 has been : instantiated before acting upon the trap. : : - for registers that only conditionally trap, we must actively trap : them even in the absence of a GICv3 being instantiated, and handle : those traps accordingly. : : - finally, ID registers must reflect the absence of a GICv3, so that : we are consistent. : : This series goes through all these requirements. The main complexity : here is to apply a GICv3 configuration on the host in the absence of a : GICv3 in the guest. This is pretty hackish, but I don't have a much : better solution so far. : : As part of making wider use of of the trap bits, we fully define the : trap routing as per the architecture, something that we eventually : need for NV anyway." : . KVM: arm64: selftests: Cope with lack of GICv3 in set_id_regs KVM: arm64: Add selftest checking how the absence of GICv3 is handled KVM: arm64: Unify UNDEF injection helpers KVM: arm64: Make most GICv3 accesses UNDEF if they trap KVM: arm64: Honor guest requested traps in GICv3 emulation KVM: arm64: Add trap routing information for ICH_HCR_EL2 KVM: arm64: Add ICH_HCR_EL2 to the vcpu state KVM: arm64: Zero ID_AA64PFR0_EL1.GIC when no GICv3 is presented to the guest KVM: arm64: Add helper for last ditch idreg adjustments KVM: arm64: Force GICv3 trap activation when no irqchip is configured on VHE KVM: arm64: Force SRE traps when SRE access is not enabled KVM: arm64: Move GICv3 trap configuration to kvm_calculate_traps() Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-12Merge branch kvm-arm64/fpmr into kvmarm-master/nextMarc Zyngier
* kvm-arm64/fpmr: : . : Add FP8 support to the KVM/arm64 floating point handling. : : This includes new ID registers (ID_AA64PFR2_EL1 ID_AA64FPFR0_EL1) : being made visible to guests, as well as a new confrol register : (FPMR) which gets context-switched. : . KVM: arm64: Expose ID_AA64PFR2_EL1 to userspace and guests KVM: arm64: Enable FP8 support when available and configured KVM: arm64: Expose ID_AA64FPFR0_EL1 as a writable ID reg KVM: arm64: Honor trap routing for FPMR KVM: arm64: Add save/restore support for FPMR KVM: arm64: Move FPMR into the sysreg array KVM: arm64: Add predicate for FPMR support in a VM KVM: arm64: Move SVCR into the sysreg array Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-12Merge branch kvm-arm64/mmu-misc-6.12 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/mmu-misc-6.12: : . : Various minor MMU improvements and bug-fixes: : : - Prevent MTE tags being restored by userspace if we are actively : logging writes, as that's a recipe for disaster : : - Correct the refcount on a page that is not considered for MTE : tag copying (such as a device) : : - When walking a page table to split blocks, keep the DSB at the end : the walk, as there is no need to perform it on every store. : : - Fix boundary check when transfering memory using FFA : . KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer KVM: arm64: Disallow copying MTE to guest memory while KVM is dirty logging KVM: arm64: Release pfn, i.e. put page, if copying MTE tags hits ZONE_DEVICE KVM: arm64: Move data barrier to end of split walk Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-11KVM: arm64: Get rid of REG_HIDDEN_USER visibility qualifierMarc Zyngier
Now that REG_HIDDEN_USER has no direct user anymore, remove it entirely and update all users of sysreg_hidden_user() to call sysreg_hidden() instead. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240904082419.1982402-4-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-11KVM: arm64: Simplify visibility handling of AArch32 SPSR_*Marc Zyngier
Since SPSR_* are not associated with any register in the sysreg array, nor do they have .get_user()/.set_user() helpers, they are invisible to userspace with that encoding. Therefore hidden_user_visibility() serves no purpose here, and can be safely removed. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240904082419.1982402-3-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-11KVM: arm64: Simplify handling of CNTKCTL_EL12Marc Zyngier
We go trough a great deal of effort to map CNTKCTL_EL12 to CNTKCTL_EL1 while hidding this mapping from userspace via a special visibility helper. However, it would be far simpler to just provide an accessor doing the mapping job, removing the need for a visibility helper. With that done, we can also remove the EL12_REG() macro which serves no purpose. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240904082419.1982402-2-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>