[PATCH v1 11/28] x86/hvm: introduce vcpu_is_vlapic_tpr_emulated()

[dmukhin@xxxxxxxx]

From: Denis Mukhin <dmukhin@xxxxxxxx>

Introduce vcpu_is_vlapic_tpr_emulated() in genetic SVM code to account
for the case when platform provides accelerated access to vLAPIC's TPR.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 673c818a0039..14a86ca4ff8f 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -925,6 +925,19 @@ static void cf_check svm_ctxt_switch_to(struct vcpu *v)
     }
 }
 
+static bool vcpu_is_vlapic_tpr_emulated(const struct vcpu *v, bool 
force_noaccel)
+{
+    const struct vlapic *vlapic = vcpu_vlapic(v);
+
+    if ( force_noaccel )
+        return false;
+
+    if ( vlapic_hw_disabled(vlapic) )
+        return false;
+
+    return true;
+}
+
 static void noreturn cf_check svm_do_resume(void)
 {
     struct vcpu *v = current;
@@ -933,7 +946,6 @@ static void noreturn cf_check svm_do_resume(void)
                         v->domain->arch.monitor.software_breakpoint_enabled ||
                         v->domain->arch.monitor.debug_exception_enabled);
     bool vcpu_guestmode = false;
-    struct vlapic *vlapic = vcpu_vlapic(v);
 
     if ( nestedhvm_enabled(v->domain) && nestedhvm_vcpu_in_guestmode(v) )
         vcpu_guestmode = 1;
@@ -959,8 +971,9 @@ static void noreturn cf_check svm_do_resume(void)
         vmcb->cleanbits.raw = 0;
     }
 
-    if ( !vcpu_guestmode && !vlapic_hw_disabled(vlapic) )
+    if ( vcpu_is_vlapic_tpr_emulated(v, vcpu_guestmode) )
     {
+        struct vlapic *vlapic = vcpu_vlapic(v);
         vintr_t intr;
 
         /* Reflect the vlapic's TPR in the hardware vtpr */
@@ -2538,7 +2551,6 @@ void asmlinkage svm_vmexit_handler(void)
     int insn_len;
     vintr_t intr;
     bool vcpu_guestmode = false;
-    struct vlapic *vlapic = vcpu_vlapic(v);
 
     regs->rax = vmcb->rax;
     regs->rip = vmcb->rip;
@@ -2565,8 +2577,10 @@ void asmlinkage svm_vmexit_handler(void)
      * 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 && !vlapic_hw_disabled(vlapic) )
+    if ( vcpu_is_vlapic_tpr_emulated(v, vcpu_guestmode) )
     {
+        struct vlapic *vlapic = vcpu_vlapic(v);
+
         intr = vmcb_get_vintr(vmcb);
         vlapic_set_reg(vlapic, APIC_TASKPRI,
                    ((intr.fields.tpr & 0x0F) << 4) |
@@ -3097,14 +3111,16 @@ void asmlinkage svm_vmexit_handler(void)
     }
 
   out:
-    if ( vcpu_guestmode || vlapic_hw_disabled(vlapic) )
-        return;
+    if ( vcpu_is_vlapic_tpr_emulated(v, vcpu_guestmode ) )
+    {
+        struct vlapic *vlapic = vcpu_vlapic(v);
 
-    /* The exit may have updated the TPR: reflect this in the hardware vtpr */
-    intr = vmcb_get_vintr(vmcb);
-    intr.fields.tpr =
-        (vlapic_get_reg(vlapic, APIC_TASKPRI) & 0xFF) >> 4;
-    vmcb_set_vintr(vmcb, intr);
+        /* The exit may have updated the TPR: reflect this in the hardware 
vtpr */
+        intr = vmcb_get_vintr(vmcb);
+        intr.fields.tpr =
+            (vlapic_get_reg(vlapic, APIC_TASKPRI) & 0xFF) >> 4;
+        vmcb_set_vintr(vmcb, intr);
+    }
 }
 
 /*
-- 
2.55.0