From 2c433f70dccc1af6922931404bfe23d215bdfff0 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:36 -0800 Subject: [PATCH] KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps 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 Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-10-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/vhe/switch.c | 22 ++++++++++++++++++++++ arch/arm64/tools/cpucaps | 1 + 2 files changed, 23 insertions(+) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 647737d6e8d0..731a0378ed13 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -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) diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index ee4316cb3690..772c1b008e43 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -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