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path: root/arch/arm64/kvm/sys_regs.c
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2022-02-25arm64: Add support of PAuth QARMA3 architected algorithmVladimir Murzin
QARMA3 is relaxed version of the QARMA5 algorithm which expected to reduce the latency of calculation while still delivering a suitable level of security. Support for QARMA3 can be discovered via ID_AA64ISAR2_EL1 APA3, bits [15:12] Indicates whether the QARMA3 algorithm is implemented in the PE for address authentication in AArch64 state. GPA3, bits [11:8] Indicates whether the QARMA3 algorithm is implemented in the PE for generic code authentication in AArch64 state. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220224124952.119612-4-vladimir.murzin@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2022-02-08KVM: arm64: Emulate the OS LockOliver Upton
The OS lock blocks all debug exceptions at every EL. To date, KVM has not implemented the OS lock for its guests, despite the fact that it is mandatory per the architecture. Simple context switching between the guest and host is not appropriate, as its effects are not constrained to the guest context. Emulate the OS Lock by clearing MDE and SS in MDSCR_EL1, thereby blocking all but software breakpoint instructions. Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220203174159.2887882-5-oupton@google.com
2022-02-08KVM: arm64: Allow guest to set the OSLK bitOliver Upton
Allow writes to OSLAR and forward the OSLK bit to OSLSR. Do nothing with the value for now. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220203174159.2887882-4-oupton@google.com
2022-02-08KVM: arm64: Stash OSLSR_EL1 in the cpu contextOliver Upton
An upcoming change to KVM will emulate the OS Lock from the PoV of the guest. Add OSLSR_EL1 to the cpu context and handle reads using the stored value. Define some mnemonics for for handling the OSLM field and use them to make the reset value of OSLSR_EL1 more readable. Wire up a custom handler for writes from userspace and prevent any of the invariant bits from changing. Note that the OSLK bit is not invariant and will be made writable by the aforementioned change. Reviewed-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220203174159.2887882-3-oupton@google.com
2022-02-08KVM: arm64: Correctly treat writes to OSLSR_EL1 as undefinedOliver Upton
Writes to OSLSR_EL1 are UNDEFINED and should never trap from EL1 to EL2, but the kvm trap handler for OSLSR_EL1 handles writes via ignore_write(). This is confusing to readers of code, but should have no functional impact. For clarity, use write_to_read_only() rather than ignore_write(). If a trap is unexpectedly taken to EL2 in violation of the architecture, this will WARN_ONCE() and inject an undef into the guest. Reviewed-by: Reiji Watanabe <reijiw@google.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> [adopted Mark's changelog suggestion, thanks!] Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220203174159.2887882-2-oupton@google.com
2021-12-13arm64: add ID_AA64ISAR2_EL1 sys registerJoey Gouly
This is a new ID register, introduced in 8.7. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Reiji Watanabe <reijiw@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211210165432.8106-3-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-10-18Merge branch kvm-arm64/pkvm/fixed-features into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm/fixed-features: (22 commits) : . : Add the pKVM fixed feature that allows a bunch of exceptions : to either be forbidden or be easily handled at EL2. : . KVM: arm64: pkvm: Give priority to standard traps over pvm handling KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array() KVM: arm64: pkvm: Move kvm_handle_pvm_restricted around KVM: arm64: pkvm: Consolidate include files KVM: arm64: pkvm: Preserve pending SError on exit from AArch32 KVM: arm64: pkvm: Handle GICv3 traps as required KVM: arm64: pkvm: Drop sysregs that should never be routed to the host KVM: arm64: pkvm: Drop AArch32-specific registers KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI KVM: arm64: pkvm: Use a single function to expose all id-regs KVM: arm64: Fix early exit ptrauth handling KVM: arm64: Handle protected guests at 32 bits KVM: arm64: Trap access to pVM restricted features KVM: arm64: Move sanitized copies of CPU features KVM: arm64: Initialize trap registers for protected VMs KVM: arm64: Add handlers for protected VM System Registers KVM: arm64: Simplify masking out MTE in feature id reg KVM: arm64: Add missing field descriptor for MDCR_EL2 KVM: arm64: Pass struct kvm to per-EC handlers KVM: arm64: Move early handlers to per-EC handlers ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-17Merge branch kvm-arm64/vgic-fixes-5.16 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/vgic-fixes-5.16: : . : Multiple updates to the GICv3 emulation in order to better support : the dreadful Apple M1 that only implements half of it, and in a : broken way... : . KVM: arm64: vgic-v3: Align emulated cpuif LPI state machine with the pseudocode KVM: arm64: vgic-v3: Don't advertise ICC_CTLR_EL1.SEIS KVM: arm64: vgic-v3: Reduce common group trapping to ICV_DIR_EL1 when possible KVM: arm64: vgic-v3: Work around GICv3 locally generated SErrors KVM: arm64: Force ID_AA64PFR0_EL1.GIC=1 when exposing a virtual GICv3 Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-17KVM: arm64: Force ID_AA64PFR0_EL1.GIC=1 when exposing a virtual GICv3Marc Zyngier
Until now, we always let ID_AA64PFR0_EL1.GIC reflect the value visible on the host, even if we were running a GICv2-enabled VM on a GICv3+compat host. That's fine, but we also now have the case of a host that does not expose ID_AA64PFR0_EL1.GIC==1 despite having a vGIC. Yes, this is confusing. Thank you M1. Let's go back to first principles and expose ID_AA64PFR0_EL1.GIC=1 when a GICv3 is exposed to the guest. This also hides a GICv4.1 CPU interface from the guest which has no business knowing about the v4.1 extension. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211010150910.2911495-2-maz@kernel.org
2021-10-11KVM: arm64: Simplify masking out MTE in feature id regFuad Tabba
Simplify code for hiding MTE support in feature id register when MTE is not enabled/supported by KVM. No functional change intended. Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211010145636.1950948-7-tabba@google.com
2021-10-11KVM: arm64: Replace get_raz_id_reg() with get_raz_reg()Alexandru Elisei
Reading a RAZ ID register isn't different from reading any other RAZ register, so get rid of get_raz_id_reg() and replace it with get_raz_reg(), which does the same thing, but does it without going through two layers of indirection. No functional change. Suggested-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211011105840.155815-4-alexandru.elisei@arm.com
2021-10-11KVM: arm64: Use get_raz_reg() for userspace reads of PMSWINC_EL0Alexandru Elisei
PMSWINC_EL0 is a write-only register and was initially part of the VCPU register state, but was later removed in commit 7a3ba3095a32 ("KVM: arm64: Remove PMSWINC_EL0 shadow register"). To prevent regressions, the register was kept accessible from userspace as Read-As-Zero (RAZ). The read function that is used to handle userspace reads of this register is get_raz_id_reg(), which, while technically correct, as it returns 0, it is not semantically correct, as PMSWINC_EL0 is not an ID register as the function name suggests. Add a new function, get_raz_reg(), to use it as the accessor for PMSWINC_EL0, as to not conflate get_raz_id_reg() to handle other types of registers. No functional change intended. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211011105840.155815-3-alexandru.elisei@arm.com
2021-10-11KVM: arm64: Return early from read_id_reg() if register is RAZAlexandru Elisei
If read_id_reg() is called for an ID register which is Read-As-Zero (RAZ), it initializes the return value to zero, then goes through a list of registers which require special handling before returning the final value. By not returning as soon as it checks that the register should be RAZ, the function creates the opportunity for bugs, if, for example, a patch changes a register to RAZ (like has happened with PMSWINC_EL0 in commit 11663111cd49), but doesn't remove the special handling from read_id_reg(); or if a register is RAZ in certain situations, but readable in others. Return early to make it impossible for a RAZ register to be anything other than zero. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211011105840.155815-2-alexandru.elisei@arm.com
2021-08-20Merge branch kvm-arm64/pkvm-fixed-features-prologue into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-fixed-features-prologue: : Rework a bunch of common infrastructure as a prologue : to Fuad Tabba's protected VM fixed feature series. KVM: arm64: Upgrade trace_kvm_arm_set_dreg32() to 64bit KVM: arm64: Add config register bit definitions KVM: arm64: Add feature register flag definitions KVM: arm64: Track value of cptr_el2 in struct kvm_vcpu_arch KVM: arm64: Keep mdcr_el2's value as set by __init_el2_debug KVM: arm64: Restore mdcr_el2 from vcpu KVM: arm64: Refactor sys_regs.h,c for nVHE reuse KVM: arm64: Fix names of config register fields KVM: arm64: MDCR_EL2 is a 64-bit register KVM: arm64: Remove trailing whitespace in comment KVM: arm64: placeholder to check if VM is protected Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-08-20KVM: arm64: Refactor sys_regs.h,c for nVHE reuseFuad Tabba
Refactor sys_regs.h and sys_regs.c to make it easier to reuse common code. It will be used in nVHE in a later patch. Note that the refactored code uses __inline_bsearch for find_reg instead of bsearch to avoid copying the bsearch code for nVHE. No functional change intended. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210817081134.2918285-6-tabba@google.com
2021-08-20KVM: arm64: Remove trailing whitespace in commentFuad Tabba
Remove trailing whitespace from comment in trap_dbgauthstatus_el1(). No functional change intended. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210817081134.2918285-3-tabba@google.com
2021-08-02KVM: arm64: Remove PMSWINC_EL0 shadow registerMarc Zyngier
We keep an entry for the PMSWINC_EL0 register in the vcpu structure, while *never* writing anything there outside of reset. Given that the register is defined as write-only, that we always trap when this register is accessed, there is little point in saving anything anyway. Get rid of the entry, and save a mighty 8 bytes per vcpu structure. We still need to keep it exposed to userspace in order to preserve backward compatibility with previously saved VMs. Since userspace cannot expect any effect of writing to PMSWINC_EL0, treat the register as RAZ/WI for the purpose of userspace access. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210719123902.1493805-5-maz@kernel.org
2021-08-02KVM: arm64: Drop unnecessary masking of PMU registersMarc Zyngier
We always sanitise our PMU sysreg on the write side, so there is no need to do it on the read side as well. Drop the unnecessary masking. Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210719123902.1493805-3-maz@kernel.org
2021-08-02KVM: arm64: Narrow PMU sysreg reset values to architectural requirementsMarc Zyngier
A number of the PMU sysregs expose reset values that are not compliant with the architecture (set bits in the RES0 ranges, for example). This in turn has the effect that we need to pointlessly mask some register fields when using them. Let's start by making sure we don't have illegal values in the shadow registers at reset time. This affects all the registers that dedicate one bit per counter, the counters themselves, PMEVTYPERn_EL0 and PMSELR_EL0. Reported-by: Alexandre Chartre <alexandre.chartre@oracle.com> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20210719123902.1493805-2-maz@kernel.org
2021-06-22KVM: arm64: Expose KVM_ARM_CAP_MTESteven Price
It's now safe for the VMM to enable MTE in a guest, so expose the capability to user space. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210621111716.37157-5-steven.price@arm.com
2021-06-22KVM: arm64: Save/restore MTE registersSteven Price
Define the new system registers that MTE introduces and context switch them. The MTE feature is still hidden from the ID register as it isn't supported in a VM yet. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210621111716.37157-4-steven.price@arm.com
2021-06-22KVM: arm64: Introduce MTE VM featureSteven Price
Add a new VM feature 'KVM_ARM_CAP_MTE' which enables memory tagging for a VM. This will expose the feature to the guest and automatically tag memory pages touched by the VM as PG_mte_tagged (and clear the tag storage) to ensure that the guest cannot see stale tags, and so that the tags are correctly saved/restored across swap. Actually exposing the new capability to user space happens in a later patch. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> [maz: move VM_SHARED sampling into the critical section] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210621111716.37157-3-steven.price@arm.com
2021-05-15KVM: arm64: Fix debug register indexingMarc Zyngier
Commit 03fdfb2690099 ("KVM: arm64: Don't write junk to sysregs on reset") flipped the register number to 0 for all the debug registers in the sysreg table, hereby indicating that these registers live in a separate shadow structure. However, the author of this patch failed to realise that all the accessors are using that particular index instead of the register encoding, resulting in all the registers hitting index 0. Not quite a valid implementation of the architecture... Address the issue by fixing all the accessors to use the CRm field of the encoding, which contains the debug register index. Fixes: 03fdfb2690099 ("KVM: arm64: Don't write junk to sysregs on reset") Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org
2021-04-13Merge branch 'kvm-arm64/debug-5.13' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-11KVM: arm64: Don't advertise FEAT_SPE to guestsAlexandru Elisei
Even though KVM sets up MDCR_EL2 to trap accesses to the SPE buffer and sampling control registers and to inject an undefined exception, the presence of FEAT_SPE is still advertised in the ID_AA64DFR0_EL1 register, if the hardware supports it. Getting an undefined exception when accessing a register usually happens for a hardware feature which is not implemented, and indeed this is how PMU emulation is handled when the virtual machine has been created without the KVM_ARM_VCPU_PMU_V3 feature. Let's be consistent and never advertise FEAT_SPE, because KVM doesn't have support for emulating it yet. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210409152154.198566-3-alexandru.elisei@arm.com
2021-04-11KVM: arm64: Don't print warning when trapping SPE registersAlexandru Elisei
KVM sets up MDCR_EL2 to trap accesses to the SPE buffer and sampling control registers and it relies on the fact that KVM injects an undefined exception for unknown registers. This mechanism of injecting undefined exceptions also prints a warning message for the host kernel; for example, when a guest tries to access PMSIDR_EL1: [ 2.691830] kvm [142]: Unsupported guest sys_reg access at: 80009e78 [800003c5] [ 2.691830] { Op0( 3), Op1( 0), CRn( 9), CRm( 9), Op2( 7), func_read }, This is unnecessary, because KVM has explicitly configured trapping of those registers and is well aware of their existence. Prevent the warning by adding the SPE registers to the list of registers that KVM emulates. The access function will inject the undefined exception. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210409152154.198566-2-alexandru.elisei@arm.com
2021-04-06KVM: arm64: Handle access to TRFCR_EL1Suzuki K Poulose
Rather than falling to an "unhandled access", inject add an explicit "undefined access" for TRFCR_EL1 access from the guest. Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210405164307.1720226-6-suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
2021-02-12Merge branch 'kvm-arm64/pmu-debug-fixes-5.11' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Correct spelling of DBGDIDR registerAlexandru Elisei
The aarch32 debug ID register is called DBG*D*IDR (emphasis added), not DBGIDR, use the correct spelling. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210128132823.35067-1-alexandru.elisei@arm.com
2021-02-03KVM: arm64: Upgrade PMU support to ARMv8.4Marc Zyngier
Upgrading the PMU code from ARMv8.1 to ARMv8.4 turns out to be pretty easy. All that is required is support for PMMIR_EL1, which is read-only, and for which returning 0 is a valid option as long as we don't advertise STALL_SLOT as an implemented event. Let's just do that and adjust what we return to the guest. Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Limit the debug architecture to ARMv8.0Marc Zyngier
Let's not pretend we support anything but ARMv8.0 as far as the debug architecture is concerned. Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Refactor filtering of ID registersMarc Zyngier
Our current ID register filtering is starting to be a mess of if() statements, and isn't going to get any saner. Let's turn it into a switch(), which has a chance of being more readable, and introduce a FEATURE() macro that allows easy generation of feature masks. No functionnal change intended. Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Add handling of AArch32 PCMEID{2,3} PMUv3 registersMarc Zyngier
Despite advertising support for AArch32 PMUv3p1, we fail to handle the PMCEID{2,3} registers, which conveniently alias with the top bits of PMCEID{0,1}_EL1. Implement these registers with the usual AA32(HI/LO) aliasing mechanism. Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Fix AArch32 PMUv3 cappingMarc Zyngier
We shouldn't expose *any* PMU capability when no PMU has been configured for this VM. Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-03KVM: arm64: Fix missing RES1 in emulation of DBGBIDRMarc Zyngier
The AArch32 CP14 DBGDIDR has bit 15 set to RES1, which our current emulation doesn't set. Just add the missing bit. Reported-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-01-14KVM: arm64: Use the reg_to_encoding() macro instead of sys_reg()Alexandru Elisei
The reg_to_encoding() macro is a wrapper over sys_reg() and conveniently takes a sys_reg_desc or a sys_reg_params argument and returns the 32 bit register encoding. Use it instead of calling sys_reg() directly. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210106144218.110665-1-alexandru.elisei@arm.com
2021-01-14KVM: arm64: Simplify handling of absent PMU system registersMarc Zyngier
Now that all PMU registers are gated behind a .visibility callback, remove the other checks against an absent PMU. Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-01-14KVM: arm64: Hide PMU registers from userspace when not availableMarc Zyngier
It appears that while we are now able to properly hide PMU registers from the guest when a PMU isn't available (either because none has been configured, the host doesn't have the PMU support compiled in, or that the HW doesn't have one at all), we are still exposing more than we should to userspace. Introduce a visibility callback gating all the PMU registers, which covers both usrespace and guest. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-12-31KVM: arm64: Remove spurious semicolon in reg_to_encoding()Marc Zyngier
Although not a problem right now, it flared up while working on some other aspects of the code-base. Remove the useless semicolon. Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-12-22KVM: arm64: Don't access PMCR_EL0 when no PMU is availableMarc Zyngier
We reset the guest's view of PMCR_EL0 unconditionally, based on the host's view of this register. It is however legal for an implementation not to provide any PMU, resulting in an UNDEF. The obvious fix is to skip the reset of this shadow register when no PMU is available, sidestepping the issue entirely. If no PMU is available, the guest is not able to request a virtual PMU anyway, so not doing nothing is the right thing to do! It is unlikely that this bug can hit any HW implementation though, as they all provide a PMU. It has been found using nested virt with the host KVM not implementing the PMU itself. Fixes: ab9468340d2bc ("arm64: KVM: Add access handler for PMCR register") Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201210083059.1277162-1-maz@kernel.org
2020-12-03Merge remote-tracking branch 'origin/kvm-arm64/csv3' into kvmarm-master/queueMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-30KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are Meltdown-safeMarc Zyngier
Cores that predate the introduction of ID_AA64PFR0_EL1.CSV3 to the ARMv8 architecture have this field set to 0, even of some of them are not affected by the vulnerability. The kernel maintains a list of unaffected cores (A53, A55 and a few others) so that it doesn't impose an expensive mitigation uncessarily. As we do for CSV2, let's expose the CSV3 property to guests that run on HW that is effectively not vulnerable. This can be reset to zero by writing to the ID register from userspace, ensuring that VMs can be migrated despite the new property being set. Reported-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27Merge branch 'kvm-arm64/cache-demux' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27KVM: arm64: CSSELR_EL1 max is 13Andrew Jones
Not counting TnD, which KVM doesn't currently consider, CSSELR_EL1 can have a maximum value of 0b1101 (13), which corresponds to an instruction cache at level 7. With CSSELR_MAX set to 12 we can only select up to cache level 6. Change it to 14. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201126134641.35231-2-drjones@redhat.com
2020-11-27Merge branch 'kvm-arm64/pmu-undef' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27KVM: arm64: Remove dead PMU sysreg decoding codeMarc Zyngier
The handling of traps in access_pmu_evcntr() has a couple of omminous "else return false;" statements that don't make any sense: the decoding tree coverse all the registers that trap to this handler, and returning false implies that we change PC, which we don't. Get rid of what is evidently dead code. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27KVM: arm64: Remove PMU RAZ/WI handlingMarc Zyngier
There is no RAZ/WI handling allowed for the PMU registers in the ARMv8 architecture. Nobody can remember how we cam to the conclusion that we could do this, but the ARMv8 ARM is pretty clear that we cannot. Remove the RAZ/WI handling of the PMU system registers when it is not configured. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27KVM: arm64: Inject UNDEF on PMU access when no PMU configuredMarc Zyngier
The ARMv8 architecture says that in the absence of FEAT_PMUv3, all the PMU-related register generate an UNDEF. Let's make sure that all our PMU handers catch this case by hooking into check_pmu_access_disabled(), and add checks in a couple of other places. Note that we still cannot deliver an exception into the guest as the offending cases are already caught by the RAZ/WI handling. But this puts us one step away to architectural compliance. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27KVM: arm64: Set ID_AA64DFR0_EL1.PMUVer to 0 when no PMU supportMarc Zyngier
We always expose the HW view of PMU in ID_AA64FDR0_EL1.PMUver, even when the PMU feature is disabled, while the architecture says that FEAT_PMUv3 not being implemented should result in this field being zero. Let's follow the architecture's guidance. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-11-27Merge branch 'kvm-arm64/copro-no-more' into kvmarm-master/nextMarc Zyngier
Signed-off-by: Marc Zyngier <maz@kernel.org>