This is a note to let you know that I've just added the patch titled
kvm: x86/pmu: Fix the compare function used by the pmu event filter
to the 5.17-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-x86-pmu-fix-the-compare-function-used-by-the-pmu.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 60a912e144bc006f5ab66c298f5457a25c909eff
Author: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Date: Tue May 17 05:12:36 2022 +0000
kvm: x86/pmu: Fix the compare function used by the pmu event filter
[ Upstream commit 4ac19ead0dfbabd8e0bfc731f507cfb0b95d6c99 ]
When returning from the compare function the u64 is truncated to an
int. This results in a loss of the high nybble[1] in the event select
and its sign if that nybble is in use. Switch from using a result that
can end up being truncated to a result that can only be: 1, 0, -1.
[1] bits 35:32 in the event select register and bits 11:8 in the event
select.
Fixes: 7ff775aca48ad ("KVM: x86/pmu: Use binary search to check filtered events")
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Message-Id: <20220517051238.2566934-1-aaronlewis@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index eca39f56c231..0604bc29f0b8 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -171,9 +171,12 @@ static bool pmc_resume_counter(struct kvm_pmc *pmc)
return true;
}
-static int cmp_u64(const void *a, const void *b)
+static int cmp_u64(const void *pa, const void *pb)
{
- return *(__u64 *)a - *(__u64 *)b;
+ u64 a = *(u64 *)pa;
+ u64 b = *(u64 *)pb;
+
+ return (a > b) - (a < b);
}
void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
