This is a note to let you know that I've just added the patch titled
arm64: KVM: pmu: Fix AArch32 cycle counter access
to the 4.8-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:
arm64-kvm-pmu-fix-aarch32-cycle-counter-access.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9e3f7a29694049edd728e2400ab57ad7553e5aa9 Mon Sep 17 00:00:00 2001
From: Wei Huang <wei@xxxxxxxxxx>
Date: Wed, 16 Nov 2016 09:20:57 +0000
Subject: arm64: KVM: pmu: Fix AArch32 cycle counter access
From: Wei Huang <wei@xxxxxxxxxx>
commit 9e3f7a29694049edd728e2400ab57ad7553e5aa9 upstream.
We're missing the handling code for the cycle counter accessed
from a 32bit guest, leading to unexpected results.
Signed-off-by: Wei Huang <wei@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -602,8 +602,14 @@ static bool access_pmu_evcntr(struct kvm
idx = ARMV8_PMU_CYCLE_IDX;
} else {
- BUG();
+ return false;
}
+ } else if (r->CRn == 0 && r->CRm == 9) {
+ /* PMCCNTR */
+ if (pmu_access_event_counter_el0_disabled(vcpu))
+ return false;
+
+ idx = ARMV8_PMU_CYCLE_IDX;
} else if (r->CRn == 14 && (r->CRm & 12) == 8) {
/* PMEVCNTRn_EL0 */
if (pmu_access_event_counter_el0_disabled(vcpu))
@@ -611,7 +617,7 @@ static bool access_pmu_evcntr(struct kvm
idx = ((r->CRm & 3) << 3) | (r->Op2 & 7);
} else {
- BUG();
+ return false;
}
if (!pmu_counter_idx_valid(vcpu, idx))
Patches currently in stable-queue which might be from wei@xxxxxxxxxx are
queue-4.8/arm64-kvm-pmu-fix-aarch32-cycle-counter-access.patch
queue-4.8/kvm-arm64-fix-the-issues-when-guest-pmccfiltr-is-configured.patch
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