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 5.10-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-event-filter.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4ac19ead0dfbabd8e0bfc731f507cfb0b95d6c99 Mon Sep 17 00:00:00 2001 From: Aaron Lewis <aaronlewis@xxxxxxxxxx> Date: Tue, 17 May 2022 05:12:36 +0000 Subject: kvm: x86/pmu: Fix the compare function used by the pmu event filter From: Aaron Lewis <aaronlewis@xxxxxxxxxx> commit 4ac19ead0dfbabd8e0bfc731f507cfb0b95d6c99 upstream. 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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kvm/pmu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -170,9 +170,12 @@ static bool pmc_resume_counter(struct kv 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) Patches currently in stable-queue which might be from aaronlewis@xxxxxxxxxx are queue-5.10/kvm-x86-pmu-fix-the-compare-function-used-by-the-pmu-event-filter.patch