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KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps

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Apple M* CPUs provide an IMPDEF trap for PMUv3 sysregs, where ESR_EL2.EC
is a reserved value (0x3F) and a sysreg-like ISS is reported in
AFSR1_EL2.

Compute a synthetic ESR for these PMUv3 traps, giving the illusion of
something architectural to the rest of KVM.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-10-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton
2025-03-05 12:26:36 -08:00
parent 56290316a4
commit 2c433f70dc
2 changed files with 23 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
arch/arm64/kvm/hyp/vhe/switch.c
View File

@@ -527,6 +527,25 @@ static bool kvm_hyp_handle_sysreg_vhe(struct kvm_vcpu *vcpu, u64 *exit_code)
return kvm_hyp_handle_sysreg(vcpu, exit_code);
}
static bool kvm_hyp_handle_impdef(struct kvm_vcpu *vcpu, u64 *exit_code)
{
u64 iss;
if (!cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS))
return false;
/*
* Compute a synthetic ESR for a sysreg trap. Conveniently, AFSR1_EL2
* is populated with a correct ISS for a sysreg trap. These fruity
* parts are 64bit only, so unconditionally set IL.
*/
iss = ESR_ELx_ISS(read_sysreg_s(SYS_AFSR1_EL2));
vcpu->arch.fault.esr_el2 = FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SYS64) |
FIELD_PREP(ESR_ELx_ISS_MASK, iss) |
ESR_ELx_IL;
return false;
}
static const exit_handler_fn hyp_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = NULL,
[ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32,
@@ -538,6 +557,9 @@ static const exit_handler_fn hyp_exit_handlers[] = {
[ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low,
[ESR_ELx_EC_ERET] = kvm_hyp_handle_eret,
[ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops,
/* Apple shenanigans */
[0x3F] = kvm_hyp_handle_impdef,
};
static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)

1
arch/arm64/tools/cpucaps
View File

@@ -105,6 +105,7 @@ WORKAROUND_CAVIUM_TX2_219_TVM
WORKAROUND_CLEAN_CACHE
WORKAROUND_DEVICE_LOAD_ACQUIRE
WORKAROUND_NVIDIA_CARMEL_CNP
WORKAROUND_PMUV3_IMPDEF_TRAPS
WORKAROUND_QCOM_FALKOR_E1003
WORKAROUND_QCOM_ORYON_CNTVOFF
WORKAROUND_REPEAT_TLBI