[PATCH v1 5/6] nestedsvm: Fix deferred event injection

[Ross Lagerwall <ross.lagerwall@citrix.com>]

If an event for L1 occurs while L2 is running, Xen should inject
VMEXIT_INTR and the event into L1.

nestedsvm_vcpu_interrupt() and nestedsvm_vmexit_defer() set this up to
be handled later by nsvm_vcpu_vmexit_inject() after the switch back to
L1. However, the code there appears to be bogus and completely ignores
the source/vector set up in the first place. Fix this by using the
values to properly inject the event.

Fixes: 9a779e4fc161 ("Implement SVM specific part for Nested Virtualization")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
---
 xen/arch/x86/hvm/svm/intr.c      |  4 ++--
 xen/arch/x86/hvm/svm/nestedsvm.c | 22 ++++++++++++++++++----
 xen/arch/x86/hvm/svm/svm.h       |  3 +++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/intr.c b/xen/arch/x86/hvm/svm/intr.c
index cf0621d2f628..8914375b6c21 100644
--- a/xen/arch/x86/hvm/svm/intr.c
+++ b/xen/arch/x86/hvm/svm/intr.c
@@ -55,7 +55,7 @@ static void svm_inject_nmi(struct vcpu *v)
         vmcb, general1_intercepts | GENERAL1_INTERCEPT_IRET);
 }
 
-static void svm_inject_extint(struct vcpu *v, int vector)
+void svm_inject_extint(struct vcpu *v, int vector)
 {
     struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
     intinfo_t event;
@@ -69,7 +69,7 @@ static void svm_inject_extint(struct vcpu *v, int vector)
     vmcb->event_inj = event;
 }
 
-static void svm_enable_intr_window(struct vcpu *v, struct hvm_intack intack)
+void svm_enable_intr_window(struct vcpu *v, struct hvm_intack intack)
 {
     struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
     uint32_t general1_intercepts = vmcb_get_general1_intercepts(vmcb);
diff --git a/xen/arch/x86/hvm/svm/nestedsvm.c b/xen/arch/x86/hvm/svm/nestedsvm.c
index 9b0bd0358ce4..d4fd838ca0b6 100644
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -733,11 +733,25 @@ nsvm_vcpu_vmexit_inject(struct vcpu *v, struct cpu_user_regs *regs,
         switch ( exitcode )
         {
         case VMEXIT_INTR:
-            if ( unlikely(ns_vmcb->event_inj.v) && nv->nv_vmentry_pending &&
-                 hvm_event_needs_reinjection(ns_vmcb->event_inj.type,
-                                             ns_vmcb->event_inj.vector) )
-                ns_vmcb->exit_int_info = ns_vmcb->event_inj;
+        {
+            struct hvm_intack intack = {
+                .source = svm->ns_vmexit.exitinfo1,
+                .vector = svm->ns_vmexit.exitinfo2
+            };
+
+            /* See the comment in svm_intr_assist() for why this is necessary */
+            if ( unlikely(vmcb->event_inj.v) ||
+                 hvm_interrupt_blocked(v, intack) )
+            {
+                svm_enable_intr_window(v, intack);
+                break;
+            }
+
+            svm_inject_extint(v, intack.vector);
+            pt_intr_post(v, intack);
             break;
+        }
+
         case VMEXIT_EXCEPTION_PF:
             ns_vmcb->_cr2 = ns_vmcb->ei.exc.cr2;
             fallthrough;
diff --git a/xen/arch/x86/hvm/svm/svm.h b/xen/arch/x86/hvm/svm/svm.h
index cfa411ad5ae1..186e0905967c 100644
--- a/xen/arch/x86/hvm/svm/svm.h
+++ b/xen/arch/x86/hvm/svm/svm.h
@@ -95,6 +95,9 @@ enum vmcb_sync_state {
 
 void svm_sync_vmcb(struct vcpu *v, enum vmcb_sync_state new_state);
 
+void svm_inject_extint(struct vcpu *v, int vector);
+void svm_enable_intr_window(struct vcpu *v, struct hvm_intack intack);
+
 #endif /* __X86_HVM_SVM_SVM_PRIV_H__ */
 
 /*
-- 
2.53.0