From 873e1da16918a83cc7440e299dda0dc7ab6db34c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 10 Apr 2020 10:47:02 -0700 Subject: [PATCH] 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 Message-Id: <20200410174703.1138-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 281436b..1fc10b8 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; -- 2.7.4