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authorNicolai Stange <nstange@suse.de>2018-07-21 22:35:28 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-15 18:14:51 +0200
commit90bc306b76b8923e365b8e59ddc6968441594970 (patch)
tree2760aba5d8fe6280d9afb7cf1a2ecc9a4abc8b4f /arch/x86/kvm/vmx.c
parent936f566260c2ae883e41301edafa1afb2ba11241 (diff)
x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush()
commit 5b6ccc6c3b1a477fbac9ec97a0b4c1c48e765209 upstream Currently, vmx_vcpu_run() checks if l1tf_flush_l1d is set and invokes vmx_l1d_flush() if so. This test is unncessary for the "always flush L1D" mode. Move the check to vmx_l1d_flush()'s conditional mode code path. Notes: - vmx_l1d_flush() is likely to get inlined anyway and thus, there's no extra function call. - This inverts the (static) branch prediction, but there hadn't been any explicit likely()/unlikely() annotations before and so it stays as is. Signed-off-by: Nicolai Stange <nstange@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
-rw-r--r--arch/x86/kvm/vmx.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 796c4eb2cd8f..df1a72b59ad2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8667,12 +8667,16 @@ static void vmx_l1d_flush(struct kvm_vcpu *vcpu)
* 'always'
*/
if (static_branch_likely(&vmx_l1d_flush_cond)) {
+ bool flush_l1d = vcpu->arch.l1tf_flush_l1d;
+
/*
* Clear the flush bit, it gets set again either from
* vcpu_run() or from one of the unsafe VMEXIT
* handlers.
*/
vcpu->arch.l1tf_flush_l1d = false;
+ if (!flush_l1d)
+ return;
}
vcpu->stat.l1d_flush++;
@@ -9162,10 +9166,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
vmx->__launched = vmx->loaded_vmcs->launched;
- if (static_branch_unlikely(&vmx_l1d_should_flush)) {
- if (vcpu->arch.l1tf_flush_l1d)
- vmx_l1d_flush(vcpu);
- }
+ if (static_branch_unlikely(&vmx_l1d_should_flush))
+ vmx_l1d_flush(vcpu);
asm(
/* Store host registers */