From: Aaron Lewis aaronlewis@google.com
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@google.com Reviewed-by: Sean Christopherson seanjc@google.com Message-Id: 20220517051238.2566934-1-aaronlewis@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)