The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 9228b26194d1cc00449f12f306f53ef2e234a55b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023040356-immerse-arming-cc39@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

9228b26194d1 ("KVM: arm64: PMU: Fix GET_ONE_REG for vPMC regs to return the current value") 0ab410a93d62 ("KVM: arm64: Narrow PMU sysreg reset values to architectural requirements") 11663111cd49 ("KVM: arm64: Hide PMU registers from userspace when not available") 7ccadf23b861 ("KVM: arm64: Add missing reset handlers for PMU emulation") 03fdfb269009 ("KVM: arm64: Don't write junk to sysregs on reset") 20589c8cc47d ("arm/arm64: KVM: Don't panic on failure to properly reset system registers")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9228b26194d1cc00449f12f306f53ef2e234a55b Mon Sep 17 00:00:00 2001 From: Reiji Watanabe reijiw@google.com Date: Sun, 12 Mar 2023 20:32:08 -0700 Subject: [PATCH] KVM: arm64: PMU: Fix GET_ONE_REG for vPMC regs to return the current value

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

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 53749d3a0996..1b2c161120be 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -856,6 +856,22 @@ static bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx) 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) @@ -1072,7 +1088,7 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, /* 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 */ @@ -1982,7 +1998,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { { 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),