This is a note to let you know that I've just added the patch titled
KVM: arm64: PMU: Restore the guest's EL0 event counting after migration
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-restore-the-guest-s-el0-event-counting-after-migration.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 f9ea835e99bc8d049bf2a3ec8fa5a7cb4fcade23 Mon Sep 17 00:00:00 2001
From: Reiji Watanabe <reijiw@xxxxxxxxxx>
Date: Tue, 28 Mar 2023 19:39:44 -0700
Subject: KVM: arm64: PMU: Restore the guest's EL0 event counting after migration
From: Reiji Watanabe <reijiw@xxxxxxxxxx>
commit f9ea835e99bc8d049bf2a3ec8fa5a7cb4fcade23 upstream.
Currently, with VHE, KVM enables the EL0 event counting for the
guest on vcpu_load() or KVM enables it as a part of the PMU
register emulation process, when needed. However, in the migration
case (with VHE), the same handling is lacking, as vPMU register
values that were restored by userspace haven't been propagated yet
(the PMU events haven't been created) at the vcpu load-time on the
first KVM_RUN (kvm_vcpu_pmu_restore_guest() called from vcpu_load()
on the first KVM_RUN won't do anything as events_{guest,host} of
kvm_pmu_events are still zero).
So, with VHE, enable the guest's EL0 event counting on the first
KVM_RUN (after the migration) when needed. More specifically,
have kvm_pmu_handle_pmcr() call kvm_vcpu_pmu_restore_guest()
so that kvm_pmu_handle_pmcr() on the first KVM_RUN can take
care of it.
Fixes: d0c94c49792c ("KVM: arm64: Restore PMU configuration on first run")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230329023944.2488484-1-reijiw@xxxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/pmu-emul.c | 1 +
arch/arm64/kvm/sys_regs.c | 1 -
2 files changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -558,6 +558,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu
for_each_set_bit(i, &mask, 32)
kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true);
}
+ kvm_vcpu_pmu_restore_guest(vcpu);
}
static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -703,7 +703,6 @@ static bool access_pmcr(struct kvm_vcpu
if (!kvm_supports_32bit_el0())
val |= ARMV8_PMU_PMCR_LC;
kvm_pmu_handle_pmcr(vcpu, val);
- kvm_vcpu_pmu_restore_guest(vcpu);
} else {
/* PMCR.P & PMCR.C are RAZ */
val = __vcpu_sys_reg(vcpu, PMCR_EL0)
Patches currently in stable-queue which might be from reijiw@xxxxxxxxxx are
queue-6.2/kvm-arm64-pmu-restore-the-guest-s-el0-event-counting-after-migration.patch
