[PATCH v2 5/6] KVM: x86: Unconditionally set l1tf_flush_l1d during vCPU load

From: Sean Christopherson
Date: Tue May 21 2024 - 21:42:00 EST


Always set l1tf_flush_l1d during kvm_arch_vcpu_load() instead of setting
it only when the vCPU is being scheduled back in. The flag is processed
only when VM-Enter is imminent, and KVM obviously needs to load the vCPU
before VM-Enter, so attempting to precisely set l1tf_flush_l1d provides no
meaningful value. I.e. the flag _will_ be set either way, it's simply a
matter of when.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 59aa772af755..60fea297f91f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5006,12 +5006,11 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);

- if (vcpu->scheduled_out) {
- vcpu->arch.l1tf_flush_l1d = true;
- if (pmu->version && unlikely(pmu->event_count)) {
- pmu->need_cleanup = true;
- kvm_make_request(KVM_REQ_PMU, vcpu);
- }
+ vcpu->arch.l1tf_flush_l1d = true;
+
+ if (vcpu->scheduled_out && pmu->version && pmu->event_count) {
+ pmu->need_cleanup = true;
+ kvm_make_request(KVM_REQ_PMU, vcpu);
}

/* Address WBINVD may be executed by guest */
--
2.45.0.215.g3402c0e53f-goog