diff options
| author | Reiji Watanabe <reijiw@google.com> | 2023-06-03 05:50:35 +0300 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-06-04 19:19:36 +0300 |
| commit | 0c2f9acf6ae74118385f7a7d48f4b2d93637b628 (patch) | |
| tree | 67a9f501d20ead1f5317bca1a38fd7bcafe17eb3 /arch/arm/include | |
| parent | 8681f71759010503892f9e3ddb05f65c0f21b690 (diff) | |
| download | linux-0c2f9acf6ae74118385f7a7d48f4b2d93637b628.tar.xz | |
KVM: arm64: PMU: Don't overwrite PMUSERENR with vcpu loaded
Currently, with VHE, KVM sets ER, CR, SW and EN bits of
PMUSERENR_EL0 to 1 on vcpu_load(), and saves and restores
the register value for the host on vcpu_load() and vcpu_put().
If the value of those bits are cleared on a pCPU with a vCPU
loaded (armv8pmu_start() would do that when PMU counters are
programmed for the guest), PMU access from the guest EL0 might
be trapped to the guest EL1 directly regardless of the current
PMUSERENR_EL0 value of the vCPU.
Fix this by not letting armv8pmu_start() overwrite PMUSERENR_EL0
on the pCPU where PMUSERENR_EL0 for the guest is loaded, and
instead updating the saved shadow register value for the host
so that the value can be restored on vcpu_put() later.
While vcpu_{put,load}() are manipulating PMUSERENR_EL0, disable
IRQs to prevent a race condition between these processes and IPIs
that attempt to update PMUSERENR_EL0 for the host EL0.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Marc Zyngier <maz@kernel.org>
Fixes: 83a7a4d643d3 ("arm64: perf: Enable PMU counter userspace access for perf event")
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230603025035.3781797-3-reijiw@google.com
Diffstat (limited to 'arch/arm/include')
| -rw-r--r-- | arch/arm/include/asm/arm_pmuv3.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arm_pmuv3.h b/arch/arm/include/asm/arm_pmuv3.h index 78d3d4b82c6c..92ddd950478e 100644 --- a/arch/arm/include/asm/arm_pmuv3.h +++ b/arch/arm/include/asm/arm_pmuv3.h @@ -222,6 +222,11 @@ static inline bool kvm_pmu_counter_deferred(struct perf_event_attr *attr) return false; } +static inline bool kvm_set_pmuserenr(u64 val) +{ + return false; +} + /* PMU Version in DFR Register */ #define ARMV8_PMU_DFR_VER_NI 0 #define ARMV8_PMU_DFR_VER_V3P4 0x5 |