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authorSean Christopherson <sean.j.christopherson@intel.com>2020-04-10 19:47:02 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2020-04-21 15:13:09 +0200
commit873e1da16918a83cc7440e299dda0dc7ab6db34c (patch)
treee09b50fd9340a143bc6c007fc97dcdbd35a913fe
parentKVM: nVMX: Remove non-functional "support" for CR3 target values (diff)
downloadlinux-873e1da16918a83cc7440e299dda0dc7ab6db34c.tar.xz
linux-873e1da16918a83cc7440e299dda0dc7ab6db34c.zip
KVM: VMX: Optimize handling of VM-Entry failures in vmx_vcpu_run()
Mark the VM-Fail, VM-Exit on VM-Enter, and #MC on VM-Enter paths as 'unlikely' so as to improve code generation so that it favors successful VM-Enter. The performance of successful VM-Enter is for more important, irrespective of whether or not success is actually likely. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200410174703.1138-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/vmx/vmx.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 281436b08e13..1fc10b821b78 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6724,11 +6724,16 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
vmx->nested.nested_run_pending = 0;
vmx->idt_vectoring_info = 0;
- vmx->exit_reason = vmx->fail ? 0xdead : vmcs_read32(VM_EXIT_REASON);
- if ((u16)vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY)
+ if (unlikely(vmx->fail)) {
+ vmx->exit_reason = 0xdead;
+ return;
+ }
+
+ vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);
+ if (unlikely((u16)vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY))
kvm_machine_check();
- if (vmx->fail || (vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
+ if (unlikely(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
return;
vmx->loaded_vmcs->launched = 1;