This is a note to let you know that I've just added the patch titled
KVM: arm64: PMU: Fix GET_ONE_REG for vPMC regs to return the current value
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm64-pmu-fix-get_one_reg-for-vpmc-regs-to-return-the-current-value.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9228b26194d1cc00449f12f306f53ef2e234a55b Mon Sep 17 00:00:00 2001
From: Reiji Watanabe <reijiw@xxxxxxxxxx>
Date: Sun, 12 Mar 2023 20:32:08 -0700
Subject: KVM: arm64: PMU: Fix GET_ONE_REG for vPMC regs to return the current value
From: Reiji Watanabe <reijiw@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230313033208.1475499-1-reijiw@xxxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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),
Patches currently in stable-queue which might be from reijiw@xxxxxxxxxx are
queue-6.2/kvm-arm64-pmu-fix-get_one_reg-for-vpmc-regs-to-return-the-current-value.patch
queue-6.2/kvm-arm64-pmu-don-t-save-pmcr_el0.-c-p-for-the-vcpu.patch
