[Devel] [PATCH 03/11] KVM: SVM: introduce nested_run_pending

[Alexander Mikhalitsyn]

From: Paolo Bonzini <pbonzini at redhat.com>

We want to inject vmexits immediately from svm_check_nested_events,
so that the interrupt/NMI window requests happen in inject_pending_event
right after it returns.

This however has the same issue as in vmx_check_nested_events, so
introduce a nested_run_pending flag with the exact same purpose
of delaying vmexit injection after the vmentry.

Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
(cherry picked from commit f74f94140fa50f768e61d626de4c146502b9102d)

https://jira.sw.ru/browse/PSBM-139278

Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn at virtuozzo.com>
---
 arch/x86/kvm/svm.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b07983892647..7bd91caeb812 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -142,6 +142,10 @@ struct nested_state {
 	/* A VMEXIT is required but not yet emulated */
 	bool exit_required;
 
+	/* A VMRUN has started but has not yet been performed, so
+	 * we cannot inject a nested vmexit yet.  */
+	bool nested_run_pending;
+
 	/* cache for intercepts of the guest */
 	u32 intercept_cr;
 	u32 intercept_dr;
@@ -2733,7 +2737,8 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	bool block_nested_events =
-		kvm_event_needs_reinjection(vcpu) || svm->nested.exit_required;
+		kvm_event_needs_reinjection(vcpu) || svm->nested.exit_required ||
+		svm->nested.nested_run_pending;
 
 	if (kvm_cpu_has_interrupt(vcpu) && nested_exit_on_intr(svm)) {
 		if (block_nested_events)
@@ -3349,6 +3354,7 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
 
 	copy_vmcb_control_area(hsave, vmcb);
 
+	svm->nested.nested_run_pending = 1;
 	enter_svm_guest_mode(svm, vmcb_gpa, nested_vmcb, page);
 
 	return true;
@@ -5349,6 +5355,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	sync_cr8_to_lapic(vcpu);
 
 	svm->next_rip = 0;
+	svm->nested.nested_run_pending = 0;
 
 	svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
 
-- 
2.36.1