From: Reiji Watanabe reijiw@google.com
commit 9228b26194d1cc00449f12f306f53ef2e234a55b upstream.
Have KVM_GET_ONE_REG for vPMU counter (vPMC) registers (PMCCNTR_EL0 and PMEVCNTR<n>_EL0) return the sum of the register value in the sysreg file and the current perf event counter value.
Values of vPMC registers are saved in sysreg files on certain occasions. These saved values don't represent the current values of the vPMC registers if the perf events for the vPMCs count events after the save. The current values of those registers are the sum of the sysreg file value and the current perf event counter value. But, when userspace reads those registers (using KVM_GET_ONE_REG), KVM returns the sysreg file value to userspace (not the sum value).
Fix this to return the sum value for KVM_GET_ONE_REG.
Fixes: 051ff581ce70 ("arm64: KVM: Add access handler for event counter register") Cc: stable@vger.kernel.org Reviewed-by: Marc Zyngier maz@kernel.org Signed-off-by: Reiji Watanabe reijiw@google.com Link: https://lore.kernel.org/r/20230313033208.1475499-1-reijiw@google.com Signed-off-by: Oliver Upton oliver.upton@linux.dev Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/sys_regs.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
--- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -765,6 +765,22 @@ static bool pmu_counter_idx_valid(struct return true; }
+static int get_pmu_evcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, + u64 *val) +{ + u64 idx; + + if (r->CRn == 9 && r->CRm == 13 && r->Op2 == 0) + /* PMCCNTR_EL0 */ + idx = ARMV8_PMU_CYCLE_IDX; + else + /* PMEVCNTRn_EL0 */ + idx = ((r->CRm & 3) << 3) | (r->Op2 & 7); + + *val = kvm_pmu_get_counter_value(vcpu, idx); + return 0; +} + static bool access_pmu_evcntr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) @@ -981,7 +997,7 @@ static bool access_pmuserenr(struct kvm_ /* Macro to expand the PMEVCNTRn_EL0 register */ #define PMU_PMEVCNTR_EL0(n) \ { PMU_SYS_REG(SYS_PMEVCNTRn_EL0(n)), \ - .reset = reset_pmevcntr, \ + .reset = reset_pmevcntr, .get_user = get_pmu_evcntr, \ .access = access_pmu_evcntr, .reg = (PMEVCNTR0_EL0 + n), }
/* Macro to expand the PMEVTYPERn_EL0 register */ @@ -1745,7 +1761,8 @@ static const struct sys_reg_desc sys_reg { PMU_SYS_REG(SYS_PMCEID1_EL0), .access = access_pmceid, .reset = NULL }, { PMU_SYS_REG(SYS_PMCCNTR_EL0), - .access = access_pmu_evcntr, .reset = reset_unknown, .reg = PMCCNTR_EL0 }, + .access = access_pmu_evcntr, .reset = reset_unknown, + .reg = PMCCNTR_EL0, .get_user = get_pmu_evcntr}, { PMU_SYS_REG(SYS_PMXEVTYPER_EL0), .access = access_pmu_evtyper, .reset = NULL }, { PMU_SYS_REG(SYS_PMXEVCNTR_EL0),