x86/pvh: disable posted interrupts

Enabling posted interrupts requires the virtual interrupt delivery feature,
which is disabled for PVH guests, so make sure posted interrupts are also
disabled or else vmlaunch will fail.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-and-Tested-by: Lars Eggert <lars@netapp.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

xen/arch/x86/hvm/vmx/vmcs.c

@@ -976,6 +976,10 @@ static int construct_vmcs(struct vcpu *v)
               | SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY);
         v->arch.hvm_vmx.exec_control &= ~CPU_BASED_TPR_SHADOW;
 
+        /* In turn, disable posted interrupts. */
+        __vmwrite(PIN_BASED_VM_EXEC_CONTROL,
+                  vmx_pin_based_exec_control & ~PIN_BASED_POSTED_INTERRUPT);
+
         /* Unrestricted guest (real mode for EPT) */
         v->arch.hvm_vmx.secondary_exec_control &=
             ~SECONDARY_EXEC_UNRESTRICTED_GUEST;