From: Sean Christopherson Date: Wed, 22 May 2024 01:40:13 +0000 (-0700) Subject: KVM: x86: Drop now-superflous setting of l1tf_flush_l1d in vcpu_run() X-Git-Tag: v6.11-rc1~89^2~15^2~10 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3dee3b187499b317a6587e2b8e9bf3d5050e5288;p=thirdparty%2Flinux.git KVM: x86: Drop now-superflous setting of l1tf_flush_l1d in vcpu_run() Now that KVM unconditionally sets l1tf_flush_l1d in kvm_arch_vcpu_load(), drop the redundant store from vcpu_run(). The flag is cleared only when VM-Enter is imminent, deep below vcpu_run(), i.e. barring a KVM bug, it's impossible for l1tf_flush_l1d to be cleared between loading the vCPU and calling vcpu_run(). Acked-by: Kai Huang Link: https://lore.kernel.org/r/20240522014013.1672962-7-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 9c9c25e2b1b9e..3038a6fd141b9 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6673,9 +6673,10 @@ static noinstr void vmx_l1d_flush(struct kvm_vcpu *vcpu) bool flush_l1d; /* - * Clear the per-vcpu flush bit, it gets set again - * either from vcpu_run() or from one of the unsafe - * VMEXIT handlers. + * Clear the per-vcpu flush bit, it gets set again if the vCPU + * is reloaded, i.e. if the vCPU is scheduled out or if KVM + * exits to userspace, or if KVM reaches one of the unsafe + * VMEXIT handlers, e.g. if KVM calls into the emulator. */ flush_l1d = vcpu->arch.l1tf_flush_l1d; vcpu->arch.l1tf_flush_l1d = false; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1f3b21fb4add2..bbfc3d9bb024b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11253,7 +11253,6 @@ static int vcpu_run(struct kvm_vcpu *vcpu) int r; vcpu->run->exit_reason = KVM_EXIT_UNKNOWN; - vcpu->arch.l1tf_flush_l1d = true; for (;;) { /*