[PATCH v1 3/6] nestedsvm: Use the correct VMCB for vGIF

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

In some cases, Xen uses the current VMCB to check/change the state of
vGIF but the current VMCB might be VMCB(0-2). Adjust the cases to use
VMCB(1) instead.

L0 may use vGIF to speed up L1 but whether L2 uses vGIF is the L1
hypervisor's choice and L0 should never need to check/change it.

Fixes: 4cd0fad64590 ("x86/svm: Add virtual GIF support")
Fixes: 05bb1116b8c1 ("x86/svm: update VGIF support")
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 xen/arch/x86/hvm/svm/nestedsvm.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/nestedsvm.c b/xen/arch/x86/hvm/svm/nestedsvm.c
index 9899cb2147b1..dca07d27d923 100644
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -1193,10 +1193,11 @@ nestedsvm_vmexit_defer(struct vcpu *v,
     uint64_t exitcode, uint64_t exitinfo1, uint64_t exitinfo2)
 {
     struct nestedsvm *svm = &vcpu_nestedsvm(v);
-    struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
+    struct nestedvcpu *nv = &vcpu_nestedhvm(v);
+    struct vmcb_struct *n1vmcb = nv->nv_n1vmcx;
 
-    if ( vmcb->_vintr.fields.vgif_enable )
-        vmcb->_vintr.fields.vgif = 0;
+    if ( n1vmcb->_vintr.fields.vgif_enable )
+        n1vmcb->_vintr.fields.vgif = 0;
     else
         svm->ns_gif = 0;
 
@@ -1460,11 +1461,12 @@ bool
 nestedsvm_gif_isset(struct vcpu *v)
 {
     struct nestedsvm *svm = &vcpu_nestedsvm(v);
-    struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
+    struct nestedvcpu *nv = &vcpu_nestedhvm(v);
+    struct vmcb_struct *n1vmcb = nv->nv_n1vmcx;
 
     /* get the vmcb gif value if using vgif */
-    if ( vmcb->_vintr.fields.vgif_enable )
-        return vmcb->_vintr.fields.vgif;
+    if ( n1vmcb->_vintr.fields.vgif_enable )
+        return n1vmcb->_vintr.fields.vgif;
     else
         return svm->ns_gif;
 }
-- 
2.53.0