From: Wanpeng Li wanpeng.li@hotmail.com
This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.
===============
[ Upstream commit 24dccf83a121b8a4ad5c2ad383a8184ef6c266ee ]
After async pf setup successfully, there is a broadcast wakeup w/ special token 0xffffffff which tells vCPU that it should wake up all processes waiting for APFs though there is no real process waiting at the moment.
The async page present tracepoint print prematurely and fails to catch the special token setup. This patch fixes it by moving the async page present tracepoint after the special token setup.
Before patch:
qemu-system-x86-8499 [006] ...1 5973.473292: kvm_async_pf_ready: token 0x0 gva 0x0
After patch:
qemu-system-x86-8499 [006] ...1 5973.473292: kvm_async_pf_ready: token 0xffffffff gva 0x0
Cc: Paolo Bonzini pbonzini@redhat.com Cc: Radim Krčmář rkrcmar@redhat.com Signed-off-by: Wanpeng Li wanpeng.li@hotmail.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e4e7d45fd551..7840d42734a1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7954,11 +7954,11 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, { struct x86_exception fault;
- trace_kvm_async_pf_ready(work->arch.token, work->gva); if (work->wakeup_all) work->arch.token = ~0; /* broadcast wakeup */ else kvm_del_async_pf_gfn(vcpu, work->arch.gfn); + trace_kvm_async_pf_ready(work->arch.token, work->gva);
if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) && !apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {