Stop kicking vCPUs in kvm_arch_sync_dirty_log() when PML is disabled.
Kicking vCPUs when PML is disabled serves no purpose and could
negatively impact guest performance.
This restores KVM's behavior to prior to 5.12 commit a018eba53870 ("KVM:
x86: Move MMU's PML logic to common code"), which replaced a
static_call_cond(kvm_x86_flush_log_dirty) with unconditional calls to
kvm_vcpu_kick().
Fixes: a018eba53870 ("KVM: x86: Move MMU's PML logic to common code")
Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 41cce5031126..af97de19b2ce 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6259,6 +6259,9 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
struct kvm_vcpu *vcpu;
unsigned long i;
+ if (!kvm_x86_ops.cpu_dirty_log_size)
+ return;
+
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_vcpu_kick(vcpu);
}
base-commit: ba8c993c3748931a307648616f68892bcb6afe28
--
2.42.0.655.g421f12c284-goog
