[PATCH v5 12/24] KVM: arm64: Use physical PMSELR for PMXEVTYPER if partitioned
From: Colton Lewis <hidden>
Date: 2025-12-09 20:52:40
Also in:
kvm, kvmarm, linux-doc, linux-kselftest, linux-perf-users, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Because PMXEVTYPER is trapped and PMSELR is not, it is not appropriate to use the virtual PMSELR register when it could be outdated and lead to an invalid write. Use the physical register when partitioned. Signed-off-by: Colton Lewis <redacted> --- arch/arm64/include/asm/arm_pmuv3.h | 7 ++++++- arch/arm64/kvm/sys_regs.c | 9 +++++++-- 2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h
index 27c4d6d47da31..60600f04b5902 100644
--- a/arch/arm64/include/asm/arm_pmuv3.h
+++ b/arch/arm64/include/asm/arm_pmuv3.h@@ -70,11 +70,16 @@ static inline u64 read_pmcr(void) return read_sysreg(pmcr_el0); } -static inline void write_pmselr(u32 val) +static inline void write_pmselr(u64 val) { write_sysreg(val, pmselr_el0); } +static inline u64 read_pmselr(void) +{ + return read_sysreg(pmselr_el0); +} + static inline void write_pmccntr(u64 val) { write_sysreg(val, pmccntr_el0);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0c9596325519b..2e6d907fa8af2 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c@@ -1199,14 +1199,19 @@ static bool writethrough_pmevtyper(struct kvm_vcpu *vcpu, struct sys_reg_params static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - u64 idx, reg; + u64 idx, reg, pmselr; if (pmu_access_el0_disabled(vcpu)) return false; if (r->CRn == 9 && r->CRm == 13 && r->Op2 == 1) { /* PMXEVTYPER_EL0 */ - idx = SYS_FIELD_GET(PMSELR_EL0, SEL, __vcpu_sys_reg(vcpu, PMSELR_EL0)); + if (kvm_vcpu_pmu_is_partitioned(vcpu)) + pmselr = read_pmselr(); + else + pmselr = __vcpu_sys_reg(vcpu, PMSELR_EL0); + + idx = SYS_FIELD_GET(PMSELR_EL0, SEL, pmselr); reg = PMEVTYPER0_EL0 + idx; } else if (r->CRn == 14 && (r->CRm & 12) == 12) { idx = ((r->CRm & 3) << 3) | (r->Op2 & 7);
--
2.52.0.239.gd5f0c6e74e-goog