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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: 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: 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>
2025-02-17arm64/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>
2024-12-05KVM: 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>
2024-10-11KVM: 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: 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>
2024-09-17Merge 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>
2024-09-12Merge 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>
2024-09-10KVM: arm64: Register ptdump with debugfs on guest creationSebastian Ene
While arch/*/mem/ptdump handles the kernel pagetable dumping code, introduce KVM/ptdump to show the guest stage-2 pagetables. The separation is necessary because most of the definitions from the stage-2 pagetable reside in the KVM path and we will be invoking functionality specific to KVM. Introduce the PTDUMP_STAGE2_DEBUGFS config. When a guest is created, register a new file entry under the guest debugfs dir which allows userspace to show the contents of the guest stage-2 pagetables when accessed. [maz: moved function prototypes from kvm_host.h to kvm_mmu.h] Signed-off-by: Sebastian Ene <sebastianene@google.com> Reviewed-by: Vincent Donnefort <vdonnefort@google.com> Link: https://lore.kernel.org/r/20240909124721.1672199-6-sebastianene@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-09-04KVM: Rename arch hooks related to per-CPU virtualization enablingSean Christopherson
Rename the per-CPU hooks used to enable virtualization in hardware to align with the KVM-wide helpers in kvm_main.c, and to better capture that the callbacks are invoked on every online CPU. No functional change intended. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-ID: <20240830043600.127750-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-08-27KVM: arm64: Add helper for last ditch idreg adjustmentsMarc Zyngier
We already have to perform a set of last-chance adjustments for NV purposes. We will soon have to do the same for the GIC, so introduce a helper for that exact purpose. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240827152517.3909653-5-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-08-07KVM: arm64: Tidying up PAuth code in KVMFuad Tabba
Tidy up some of the PAuth trapping code to clear up some comments and avoid clang/checkpatch warnings. Also, don't bother setting PAuth HCR_EL2 bits in pKVM, since it's handled by the hypervisor. Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240722163311.1493879-1-tabba@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-08-02KVM: arm64: fix kdoc warnings in W=1 buildsSebastian Ott
Fix kdoc warnings by adding missing function parameter descriptions or by conversion to a normal comment. Signed-off-by: Sebastian Ott <sebott@redhat.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240723101204.7356-3-sebott@redhat.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-16Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM generic changes for 6.11 - Enable halt poll shrinking by default, as Intel found it to be a clear win. - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86. - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out(). - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs. - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout. - A few minor cleanups
2024-07-14Merge branch kvm-arm64/nv-sve into kvmarm/nextOliver Upton
* kvm-arm64/nv-sve: : CPTR_EL2, FPSIMD/SVE support for nested : : This series brings support for honoring the guest hypervisor's CPTR_EL2 : trap configuration when running a nested guest, along with support for : FPSIMD/SVE usage at L1 and L2. KVM: arm64: Allow the use of SVE+NV KVM: arm64: nv: Add additional trap setup for CPTR_EL2 KVM: arm64: nv: Add trap description for CPTR_EL2 KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2 KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap KVM: arm64: nv: Handle CPACR_EL1 traps KVM: arm64: Spin off helper for programming CPTR traps KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state KVM: arm64: nv: Use guest hypervisor's max VL when running nested guest KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context KVM: arm64: nv: Load guest hyp's ZCR into EL1 state KVM: arm64: nv: Handle ZCR_EL2 traps KVM: arm64: nv: Forward SVE traps to guest hypervisor KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-14Merge branch kvm-arm64/ctr-el0 into kvmarm/nextOliver Upton
* kvm-arm64/ctr-el0: : Support for user changes to CTR_EL0, courtesy of Sebastian Ott : : Allow userspace to change the guest-visible value of CTR_EL0 for a VM, : so long as the requested value represents a subset of features supported : by hardware. In other words, prevent the VMM from over-promising the : capabilities of hardware. : : Make this happen by fitting CTR_EL0 into the existing infrastructure for : feature ID registers. KVM: selftests: Assert that MPIDR_EL1 is unchanged across vCPU reset KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking KVM: selftests: arm64: Test writes to CTR_EL0 KVM: arm64: rename functions for invariant sys regs KVM: arm64: show writable masks for feature registers KVM: arm64: Treat CTR_EL0 as a VM feature ID register KVM: arm64: unify code to prepare traps KVM: arm64: nv: Use accessors for modifying ID registers KVM: arm64: Add helper for writing ID regs KVM: arm64: Use read-only helper for reading VM ID registers KVM: arm64: Make idregs debugfs iterator search sysreg table directly KVM: arm64: Get sys_reg encoding from descriptor in idregs_debug_show() Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-14Merge branch kvm-arm64/shadow-mmu into kvmarm/nextOliver Upton
* kvm-arm64/shadow-mmu: : Shadow stage-2 MMU support for NV, courtesy of Marc Zyngier : : Initial implementation of shadow stage-2 page tables to support a guest : hypervisor. In the author's words: : : So here's the 10000m (approximately 30000ft for those of you stuck : with the wrong units) view of what this is doing: : : - for each {VMID,VTTBR,VTCR} tuple the guest uses, we use a : separate shadow s2_mmu context. This context has its own "real" : VMID and a set of page tables that are the combination of the : guest's S2 and the host S2, built dynamically one fault at a time. : : - these shadow S2 contexts are ephemeral, and behave exactly as : TLBs. For all intent and purposes, they *are* TLBs, and we discard : them pretty often. : : - TLB invalidation takes three possible paths: : : * either this is an EL2 S1 invalidation, and we directly emulate : it as early as possible : : * or this is an EL1 S1 invalidation, and we need to apply it to : the shadow S2s (plural!) that match the VMID set by the L1 guest : : * or finally, this is affecting S2, and we need to teardown the : corresponding part of the shadow S2s, which invalidates the TLBs KVM: arm64: nv: Truely enable nXS TLBI operations KVM: arm64: nv: Add handling of NXS-flavoured TLBI operations KVM: arm64: nv: Add handling of range-based TLBI operations KVM: arm64: nv: Add handling of outer-shareable TLBI operations KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level KVM: arm64: nv: Handle FEAT_TTL hinted TLB operations KVM: arm64: nv: Handle TLBI IPAS2E1{,IS} operations KVM: arm64: nv: Handle TLBI ALLE1{,IS} operations KVM: arm64: nv: Handle TLBI VMALLS12E1{,IS} operations KVM: arm64: nv: Handle TLB invalidation targeting L2 stage-1 KVM: arm64: nv: Handle EL2 Stage-1 TLB invalidation KVM: arm64: nv: Add Stage-1 EL2 invalidation primitives KVM: arm64: nv: Unmap/flush shadow stage 2 page tables KVM: arm64: nv: Handle shadow stage 2 page faults KVM: arm64: nv: Implement nested Stage-2 page table walk logic KVM: arm64: nv: Support multiple nested Stage-2 mmu structures Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: Allow the use of SVE+NVOliver Upton
Allow SVE and NV to mix now that everything is in place to handle it correctly. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-16-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: unify code to prepare trapsSebastian Ott
There are 2 functions to calculate traps via HCR_EL2: * kvm_init_sysreg() called via KVM_RUN (before the 1st run or when the pid changes) * vcpu_reset_hcr() called via KVM_ARM_VCPU_INIT To unify these 2 and to support traps that are dependent on the ID register configuration, move the code from vcpu_reset_hcr() to sys_regs.c and call it via kvm_init_sysreg(). We still have to keep the non-FWB handling stuff in vcpu_reset_hcr(). Also the initialization with HCR_GUEST_FLAGS is kept there but guarded by !vcpu_has_run_once() to ensure that previous calculated values don't get overwritten. While at it rename kvm_init_sysreg() to kvm_calculate_traps() to better reflect what it's doing. Signed-off-by: Sebastian Ott <sebott@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20240619174036.483943-7-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-19KVM: arm64: nv: Support multiple nested Stage-2 mmu structuresMarc Zyngier
Add Stage-2 mmu data structures for virtual EL2 and for nested guests. We don't yet populate shadow Stage-2 page tables, but we now have a framework for getting to a shadow Stage-2 pgd. We allocate twice the number of vcpus as Stage-2 mmu structures because that's sufficient for each vcpu running two translation regimes without having to flush the Stage-2 page tables. Co-developed-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240614144552.2773592-2-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-18KVM: Introduce vcpu->wants_to_runDavid Matlack
Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit was not set. Replace all references to vcpu->run->immediate_exit with !vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a malicious userspace could invoked KVM_RUN with immediate_exit=true and then after KVM reads it to set wants_to_run=false, flip it to false. This would result in the vCPU running in KVM_RUN with wants_to_run=false. This wouldn't cause any real bugs today but is a dangerous landmine. Signed-off-by: David Matlack <dmatlack@google.com> Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-06-14KVM: arm64: Add early_param to control WFx trappingColton Lewis
Add an early_params to control WFI and WFE trapping. This is to control the degree guests can wait for interrupts on their own without being trapped by KVM. Options for each param are trap and notrap. trap enables the trap. notrap disables the trap. Note that when enabled, traps are allowed but not guaranteed by the CPU architecture. Absent an explicitly set policy, default to current behavior: disabling the trap if only a single task is running and enabling otherwise. Signed-off-by: Colton Lewis <coltonlewis@google.com> Reviewed-by: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20240523174056.1565133-1-coltonlewis@google.com [ oliver: rework kvm_vcpu_should_clear_tw*() for readability ] Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-04KVM: arm64: Consolidate initializing the host data's fpsimd_state/sve in pKVMFuad Tabba
Now that we have introduced finalize_init_hyp_mode(), lets consolidate the initializing of the host_data fpsimd_state and sve state. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20240603122852.3923848-8-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Allocate memory mapped at hyp for host sve state in pKVMFuad Tabba
Protected mode needs to maintain (save/restore) the host's sve state, rather than relying on the host kernel to do that. This is to avoid leaking information to the host about guests and the type of operations they are performing. As a first step towards that, allocate memory mapped at hyp, per cpu, for the host sve state. The following patch will use this memory to save/restore the host state. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-6-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-09Merge branch kvm-arm64/mpidr-reset into kvmarm-master/nextMarc Zyngier
* kvm-arm64/mpidr-reset: : . : Fixes for CLIDR_EL1 and MPIDR_EL1 being accidentally mutable across : a vcpu reset, courtesy of Oliver. From the cover letter: : : "For VM-wide feature ID registers we ensure they get initialized once for : the lifetime of a VM. On the other hand, vCPU-local feature ID registers : get re-initialized on every vCPU reset, potentially clobbering the : values userspace set up. : : MPIDR_EL1 and CLIDR_EL1 are the only registers in this space that we : allow userspace to modify for now. Clobbering the value of MPIDR_EL1 has : some disastrous side effects as the compressed index used by the : MPIDR-to-vCPU lookup table assumes MPIDR_EL1 is immutable after KVM_RUN. : : Series + reproducer test case to address the problem of KVM wiping out : userspace changes to these registers. Note that there are still some : differences between VM and vCPU scoped feature ID registers from the : perspective of userspace. We do not allow the value of VM-scope : registers to change after KVM_RUN, but vCPU registers remain mutable." : . KVM: selftests: arm64: Test vCPU-scoped feature ID registers KVM: selftests: arm64: Test that feature ID regs survive a reset KVM: selftests: arm64: Store expected register value in set_id_regs KVM: selftests: arm64: Rename helper in set_id_regs to imply VM scope KVM: arm64: Only reset vCPU-scoped feature ID regs once KVM: arm64: Reset VM feature ID regs from kvm_reset_sys_regs() KVM: arm64: Rename is_id_reg() to imply VM scope Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-09KVM: arm64: Only reset vCPU-scoped feature ID regs onceOliver Upton
The general expecation with feature ID registers is that they're 'reset' exactly once by KVM for the lifetime of a vCPU/VM, such that any userspace changes to the CPU features / identity are honored after a vCPU gets reset (e.g. PSCI_ON). KVM handles what it calls VM-scoped feature ID registers correctly, but feature ID registers local to a vCPU (CLIDR_EL1, MPIDR_EL1) get wiped after every reset. What's especially concerning is that a potentially-changing MPIDR_EL1 breaks MPIDR compression for indexing mpidr_data, as the mask of useful bits to build the index could change. This is absolutely no good. Avoid resetting vCPU feature ID registers more than once. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240502233529.1958459-4-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-08Merge branch kvm-arm64/misc-6.10 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/misc-6.10: : . : Misc fixes and updates targeting 6.10 : : - Improve boot-time diagnostics when the sysreg tables : are not correctly sorted : : - Allow FFA_MSG_SEND_DIRECT_REQ in the FFA proxy : : - Fix duplicate XNX field in the ID_AA64MMFR1_EL1 : writeable mask : : - Allocate PPIs and SGIs outside of the vcpu structure, allowing : for smaller EL2 mapping and some flexibility in implementing : more or less than 32 private IRQs. : : - Use bitmap_gather() instead of its open-coded equivalent : : - Make protected mode use hVHE if available : : - Purge stale mpidr_data if a vcpu is created after the MPIDR : map has been created : . KVM: arm64: Destroy mpidr_data for 'late' vCPU creation KVM: arm64: Use hVHE in pKVM by default on CPUs with VHE support KVM: arm64: Fix hvhe/nvhe early alias parsing KVM: arm64: Convert kvm_mpidr_index() to bitmap_gather() KVM: arm64: vgic: Allocate private interrupts on demand KVM: arm64: Remove duplicated AA64MMFR1_EL1 XNX KVM: arm64: Remove FFA_MSG_SEND_DIRECT_REQ from the denylist KVM: arm64: Improve out-of-order sysreg table diagnostics Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-08KVM: arm64: Destroy mpidr_data for 'late' vCPU creationOliver Upton
A particularly annoying userspace could create a vCPU after KVM has computed mpidr_data for the VM, either by racing against VGIC initialization or having a userspace irqchip. In any case, this means mpidr_data no longer fully describes the VM, and attempts to find the new vCPU with kvm_mpidr_to_vcpu() will fail. The fix is to discard mpidr_data altogether, as it is only a performance optimization and not required for correctness. In all likelihood KVM will recompute the mappings when KVM_RUN is called on the new vCPU. Note that reads of mpidr_data are not guarded by a lock; promote to RCU to cope with the possibility of mpidr_data being invalidated at runtime. Fixes: 54a8006d0b49 ("KVM: arm64: Fast-track kvm_mpidr_to_vcpu() when mpidr_data is available") Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240508071952.2035422-1-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03Merge branch kvm-arm64/pkvm-6.10 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-6.10: (25 commits) : . : At last, a bunch of pKVM patches, courtesy of Fuad Tabba. : From the cover letter: : : "This series is a bit of a bombay-mix of patches we've been : carrying. There's no one overarching theme, but they do improve : the code by fixing existing bugs in pKVM, refactoring code to : make it more readable and easier to re-use for pKVM, or adding : functionality to the existing pKVM code upstream." : . KVM: arm64: Force injection of a data abort on NISV MMIO exit KVM: arm64: Restrict supported capabilities for protected VMs KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap() KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst KVM: arm64: Rename firmware pseudo-register documentation file KVM: arm64: Reformat/beautify PTP hypercall documentation KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit KVM: arm64: Introduce and use predicates that check for protected VMs KVM: arm64: Add is_pkvm_initialized() helper KVM: arm64: Simplify vgic-v3 hypercalls KVM: arm64: Move setting the page as dirty out of the critical section KVM: arm64: Change kvm_handle_mmio_return() return polarity KVM: arm64: Fix comment for __pkvm_vcpu_init_traps() KVM: arm64: Prevent kmemleak from accessing .hyp.data KVM: arm64: Do not map the host fpsimd state to hyp in pKVM KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE KVM: arm64: Support TLB invalidation in guest context KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE KVM: arm64: Check for PTE validity when checking for executable/cacheable KVM: arm64: Avoid BUG-ing from the host abort path ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03Merge branch kvm-arm64/nv-eret-pauth into kvmarm-master/nextMarc Zyngier
* kvm-arm64/nv-eret-pauth: : . : Add NV support for the ERETAA/ERETAB instructions. From the cover letter: : : "Although the current upstream NV support has *some* support for : correctly emulating ERET, that support is only partial as it doesn't : support the ERETAA and ERETAB variants. : : Supporting these instructions was cast aside for a long time as it : involves implementing some form of PAuth emulation, something I wasn't : overly keen on. But I have reached a point where enough of the : infrastructure is there that it actually makes sense. So here it is!" : . KVM: arm64: nv: Work around lack of pauth support in old toolchains KVM: arm64: Drop trapping of PAuth instructions/keys KVM: arm64: nv: Advertise support for PAuth KVM: arm64: nv: Handle ERETA[AB] instructions KVM: arm64: nv: Add emulation for ERETAx instructions KVM: arm64: nv: Add kvm_has_pauth() helper KVM: arm64: nv: Reinject PAC exceptions caused by HCR_EL2.API==0 KVM: arm64: nv: Handle HCR_EL2.{API,APK} independently KVM: arm64: nv: Honor HFGITR_EL2.ERET being set KVM: arm64: nv: Fast-track 'InHost' exception returns KVM: arm64: nv: Add trap forwarding for ERET and SMC KVM: arm64: nv: Configure HCR_EL2 for FEAT_NV2 KVM: arm64: nv: Drop VCPU_HYP_CONTEXT flag KVM: arm64: Constraint PAuth support to consistent implementations KVM: arm64: Add helpers for ESR_ELx_ERET_ISS_ERET* KVM: arm64: Harden __ctxt_sys_reg() against out-of-range values Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03Merge branch kvm-arm64/host_data into kvmarm-master/nextMarc Zyngier
* kvm-arm64/host_data: : . : Rationalise the host-specific data to live as part of the per-CPU state. : : From the cover letter: : : "It appears that over the years, we have accumulated a lot of cruft in : the kvm_vcpu_arch structure. Part of the gunk is data that is strictly : host CPU specific, and this result in two main problems: : : - the structure itself is stupidly large, over 8kB. With the : arch-agnostic kvm_vcpu, we're above 10kB, which is insane. This has : some ripple effects, as we need physically contiguous allocation to : be able to map it at EL2 for !VHE. There is more to it though, as : some data structures, although per-vcpu, could be allocated : separately. : : - We lose track of the life-cycle of this data, because we're : guaranteed that it will be around forever and we start relying on : wrong assumptions. This is becoming a maintenance burden. : : This series rectifies some of these things, starting with the two main : offenders: debug and FP, a lot of which gets pushed out to the per-CPU : host structure. Indeed, their lifetime really isn't that of the vcpu, : but tied to the physical CPU the vpcu runs on. : : This results in a small reduction of the vcpu size, but mainly a much : clearer understanding of the life-cycle of these structures." : . KVM: arm64: Move management of __hyp_running_vcpu to load/put on VHE KVM: arm64: Exclude FP ownership from kvm_vcpu_arch KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch KVM: arm64: Exclude mdcr_el2_host from kvm_vcpu_arch KVM: arm64: Exclude host_debug_data from vcpu_arch KVM: arm64: Add accessor for per-CPU state Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Restrict supported capabilities for protected VMsFuad Tabba
For practical reasons as well as security related ones, not all capabilities are supported for protected VMs in pKVM. Add a function that restricts the capabilities for protected VMs. This behaves as an allow-list to ensure that future capabilities are checked for compatibility and security before being allowed for protected VMs. Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-30-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap()Fuad Tabba
Initialize r = -EINVAL to get rid of the error-path initializations in kvm_vm_ioctl_enable_cap(). No functional change intended. Suggested-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-29-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Simplify vgic-v3 hypercallsMarc Zyngier
Consolidate the GICv3 VMCR accessor hypercalls into the APR save/restore hypercalls so that all of the EL2 GICv3 state is covered by a single pair of hypercalls. Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-17-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Change kvm_handle_mmio_return() return polarityFuad Tabba
Most exit handlers return <= 0 to indicate that the host needs to handle the exit. Make kvm_handle_mmio_return() consistent with the exit handlers in handle_exit(). This makes the code easier to reason about, and makes it easier to add other handlers in future patches. No functional change intended. Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-15-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-20KVM: arm64: Drop trapping of PAuth instructions/keysMarc Zyngier
We currently insist on disabling PAuth on vcpu_load(), and get to enable it on first guest use of an instruction or a key (ignoring the NV case for now). It isn't clear at all what this is trying to achieve: guests tend to use PAuth when available, and nothing forces you to expose it to the guest if you don't want to. This also isn't totally free: we take a full GPR save/restore between host and guest, only to write ten 64bit registers. The "value proposition" escapes me. So let's forget this stuff and enable PAuth eagerly if exposed to the guest. This results in much simpler code. Performance wise, that's not bad either (tested on M2 Pro running a fully automated Debian installer as the workload): - On a non-NV guest, I can see reduction of 0.24% in the number of cycles (measured with perf over 10 consecutive runs) - On a NV guest (L2), I see a 2% reduction in wall-clock time (measured with 'time', as M2 doesn't have a PMUv3 and NV doesn't support it either) So overall, a much reduced complexity and a (small) performance improvement. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240419102935.1935571-16-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-20KVM: arm64: Constraint PAuth support to consistent implementationsMarc Zyngier
PAuth comes it two parts: address authentication, and generic authentication. So far, KVM mandates that both are implemented. PAuth also comes in three flavours: Q5, Q3, and IMPDEF. Only one can be implemented for any of address and generic authentication. Crucially, the architecture doesn't mandate that address and generic authentication implement the *same* flavour. This would make implementing ERETAx very difficult for NV, something we are not terribly keen on. So only allow PAuth support for KVM on systems that are not totally insane. Which is so far 100% of the known HW. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240419102935.1935571-4-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Exclude FP ownership from kvm_vcpu_archMarc Zyngier
In retrospect, it is fairly obvious that the FP state ownership is only meaningful for a given CPU, and that locating this information in the vcpu was just a mistake. Move the ownership tracking into the host data structure, and rename it from fp_state to fp_owner, which is a better description (name suggested by Mark Brown). Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Add accessor for per-CPU stateMarc Zyngier
In order to facilitate the introduction of new per-CPU state, add a new host_data_ptr() helped that hides some of the per-CPU verbosity, and make it easier to move that state around in the future. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-01KVM: arm64: Rationalise KVM banner outputMarc Zyngier
We are not very consistent when it comes to displaying which mode we're in (VHE, {n,h}VHE, protected or not). For example, booting in protected mode with hVHE results in: [ 0.969545] kvm [1]: Protected nVHE mode initialized successfully which is mildly amusing considering that the machine is VHE only. We already cleaned this up a bit with commit 1f3ca7023fe6 ("KVM: arm64: print Hyp mode"), but that's still unsatisfactory. Unify the three strings into one and use a mess of conditional statements to sort it out (yes, it's a slow day). Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240321173706.3280796-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-03-07Merge branch kvm-arm64/vm-configuration into kvmarm/nextOliver Upton
* kvm-arm64/vm-configuration: (29 commits) : VM configuration enforcement, courtesy of Marc Zyngier : : Userspace has gained the ability to control the features visible : through the ID registers, yet KVM didn't take this into account as the : effective feature set when determing trap / emulation behavior. This : series adds: : : - Mechanism for testing the presence of a particular CPU feature in the : guest's ID registers : : - Infrastructure for computing the effective value of VNCR-backed : registers, taking into account the RES0 / RES1 bits for a particular : VM configuration : : - Implementation of 'fine-grained UNDEF' controls that shadow the FGT : register definitions. KVM: arm64: Don't initialize idreg debugfs w/ preemption disabled KVM: arm64: Fail the idreg iterator if idregs aren't initialized KVM: arm64: Make build-time check of RES0/RES1 bits optional KVM: arm64: Add debugfs file for guest's ID registers KVM: arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later checking KVM: arm64: Make FEAT_MOPS UNDEF if not advertised to the guest KVM: arm64: Make AMU sysreg UNDEF if FEAT_AMU is not advertised to the guest KVM: arm64: Make PIR{,E0}_EL1 UNDEF if S1PIE is not advertised to the guest KVM: arm64: Make TLBI OS/Range UNDEF if not advertised to the guest KVM: arm64: Streamline save/restore of HFG[RW]TR_EL2 KVM: arm64: Move existing feature disabling over to FGU infrastructure KVM: arm64: Propagate and handle Fine-Grained UNDEF bits KVM: arm64: Add Fine-Grained UNDEF tracking information KVM: arm64: Rename __check_nv_sr_forward() to triage_sysreg_trap() KVM: arm64: Use the xarray as the primary sysreg/sysinsn walker KVM: arm64: Register AArch64 system register entries with the sysreg xarray KVM: arm64: Always populate the trap configuration xarray KVM: arm64: nv: Move system instructions to their own sys_reg_desc array KVM: arm64: Drop the requirement for XARRAY_MULTI KVM: arm64: nv: Turn encoding ranges into discrete XArray stores ... Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-27KVM: arm64: Don't initialize idreg debugfs w/ preemption disabledOliver Upton
Testing KVM with DEBUG_ATOMIC_SLEEP enabled doesn't get far before hitting the first splat: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 13062, name: vgic_lpi_stress preempt_count: 1, expected: 0 2 locks held by vgic_lpi_stress/13062: #0: ffff080084553240 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xc0/0x13f0 #1: ffff800080485f08 (&kvm->arch.config_lock){+.+.}-{3:3}, at: kvm_arch_vcpu_ioctl+0xd60/0x1788 CPU: 19 PID: 13062 Comm: vgic_lpi_stress Tainted: G W O 6.8.0-dbg-DEV #1 Call trace: dump_backtrace+0xf8/0x148 show_stack+0x20/0x38 dump_stack_lvl+0xb4/0xf8 dump_stack+0x18/0x40 __might_resched+0x248/0x2a0 __might_sleep+0x50/0x88 down_write+0x30/0x150 start_creating+0x90/0x1a0 __debugfs_create_file+0x5c/0x1b0 debugfs_create_file+0x34/0x48 kvm_reset_sys_regs+0x120/0x1e8 kvm_reset_vcpu+0x148/0x270 kvm_arch_vcpu_ioctl+0xddc/0x1788 kvm_vcpu_ioctl+0xb6c/0x13f0 __arm64_sys_ioctl+0x98/0xd8 invoke_syscall+0x48/0x108 el0_svc_common+0xb4/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x54/0x128 el0t_64_sync_handler+0x68/0xc0 el0t_64_sync+0x1a8/0x1b0 kvm_reset_vcpu() disables preemption as it needs to unload vCPU state from the CPU to twiddle with it, which subsequently explodes when taking the parent inode's rwsem while creating the idreg debugfs file. Fix it by moving the initialization to kvm_arch_create_vm_debugfs(). Fixes: 891766581dea ("KVM: arm64: Add debugfs file for guest's ID registers") Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240227094115.1723330-3-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: Move existing feature disabling over to FGU infrastructureMarc Zyngier
We already trap a bunch of existing features for the purpose of disabling them (MAIR2, POR, ACCDATA, SME...). Let's move them over to our brand new FGU infrastructure. Reviewed-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240214131827.2856277-20-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: nv: Add sanitising to VNCR-backed sysregsMarc Zyngier
VNCR-backed "registers" are actually only memory. Which means that there is zero control over what the guest can write, and that it is the hypervisor's job to actually sanitise the content of the backing store. Yeah, this is fun. In order to preserve some form of sanity, add a repainting mechanism that makes use of a per-VM set of RES0/RES1 masks, one pair per VNCR register. These masks get applied on access to the backing store via __vcpu_sys_reg(), ensuring that the state that is consumed by KVM is correct. So far, nothing populates these masks, but stay tuned. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20240214131827.2856277-4-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-12KVM: arm64: print Hyp modeJoey Gouly
Print which of the hyp modes is being used (hVHE, nVHE). Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20240209103719.3813599-1-joey.gouly@arm.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-01-08Merge tag 'kvm-x86-generic-6.8' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
Common KVM changes for 6.8: - Use memdup_array_user() to harden against overflow. - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
2024-01-08Merge tag 'kvmarm-6.8' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for Linux 6.8 - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base granule sizes. Branch shared with the arm64 tree. - Large Fine-Grained Trap rework, bringing some sanity to the feature, although there is more to come. This comes with a prefix branch shared with the arm64 tree. - Some additional Nested Virtualization groundwork, mostly introducing the NV2 VNCR support and retargetting the NV support to that version of the architecture. - A small set of vgic fixes and associated cleanups.
2023-12-19Merge branch kvm-arm64/nv-6.8-prefix into kvmarm-master/nextMarc Zyngier
* kvm-arm64/nv-6.8-prefix: : . : Nested Virtualization support update, focussing on the : NV2 support (VNCR mapping and such). : . KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() KVM: arm64: nv: Map VNCR-capable registers to a separate page KVM: arm64: nv: Add EL2_REG_VNCR()/EL2_REG_REDIR() sysreg helpers KVM: arm64: Introduce a bad_trap() primitive for unexpected trap handling KVM: arm64: nv: Add include containing the VNCR_EL2 offsets KVM: arm64: nv: Add non-VHE-EL2->EL1 translation helpers KVM: arm64: nv: Drop EL12 register traps that are redirected to VNCR KVM: arm64: nv: Compute NV view of idregs as a one-off KVM: arm64: nv: Hoist vcpu_has_nv() into is_hyp_ctxt() arm64: cpufeatures: Restrict NV support to FEAT_NV2 Signed-off-by: Marc Zyngier <maz@kernel.org>