[V0 PATCH 4/6] AMD-PVH: Do not get/set vlapic TPR

[Mukesh Rathor <mukesh.rathor@oracle.com>]

PVH doesn't use apic emulation hence vlapic->regs ptr is not set for it.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/hvm/svm/svm.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index dac16f4..4bb4ff2 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1052,7 +1052,7 @@ static void noreturn svm_do_resume(struct vcpu *v)
         hvm_asid_flush_vcpu(v);
     }
 
-    if ( !vcpu_guestmode )
+    if ( !vcpu_guestmode && vcpu_vlapic(v)->regs )
     {
         vintr_t intr;
 
@@ -2247,7 +2247,7 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
      * NB. We need to preserve the low bits of the TPR to make checked builds
      * of Windows work, even though they don't actually do anything.
      */
-    if ( !vcpu_guestmode ) {
+    if ( !vcpu_guestmode && vcpu_vlapic(v)->regs ) {
         intr = vmcb_get_vintr(vmcb);
         vlapic_set_reg(vcpu_vlapic(v), APIC_TASKPRI,
                    ((intr.fields.tpr & 0x0F) << 4) |
@@ -2628,15 +2628,18 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
     }
 
   out:
-    if ( vcpu_guestmode )
-        /* Don't clobber TPR of the nested guest. */
-        return;
-
-    /* The exit may have updated the TPR: reflect this in the hardware vtpr */
-    intr = vmcb_get_vintr(vmcb);
-    intr.fields.tpr =
-        (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0xFF) >> 4;
-    vmcb_set_vintr(vmcb, intr);
+    /* Don't clobber TPR of the nested guest. */
+    if ( vcpu_guestmode && vcpu_vlapic(v)->regs )
+    {
+        /*
+         * The exit may have updated the TPR: reflect this in the hardware
+         * vtpr.
+         */
+        intr = vmcb_get_vintr(vmcb);
+        intr.fields.tpr =
+            (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0xFF) >> 4;
+        vmcb_set_vintr(vmcb, intr);
+    }
 }
 
 void svm_trace_vmentry(void)
-- 
1.8.3.1