On 1/14/22 11:54, Li RongQing wrote:
After support paravirtualized TLB shootdowns, steal_time.preempted includes not only KVM_VCPU_PREEMPTED, but also KVM_VCPU_FLUSH_TLB and kvm_vcpu_is_preempted should test only with KVM_VCPU_PREEMPTED Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> --- diff with v1: clear the rest of rax, suggested by Sean and peter remove Fixes tag, since no issue in practice arch/x86/kernel/kvm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index b061d17..45c9ce8d 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -1025,8 +1025,8 @@ asm( ".type __raw_callee_save___kvm_vcpu_is_preempted, @function;" "__raw_callee_save___kvm_vcpu_is_preempted:" "movq __per_cpu_offset(,%rdi,8), %rax;" -"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);" -"setne %al;" +"movb " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax), %al;" +"and $" __stringify(KVM_VCPU_PREEMPTED) ", %rax;"
This assumes that KVM_VCPU_PREEMPTED is 1. It could also be %eax (slightly cheaper). Overall, I prefer to leave the code as is using setne.
Paolo
"ret;" ".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;" ".popsection");
