[V9 PATCH 7/8] pvh dom0: check for vioapic null ptr in vioapic_range

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

pvh doesn't use apic emulation, as a result vioapic_init is not called
and vioapic ptr in struct hvm_domain is not initialized. One path that
would access the ptr for pvh is :

   hvm_hap_nested_page_fault -> handle_mmio -> hvmemul_do_io ->
       hvm_mmio_intercept -> vioapic_range

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/hvm/vioapic.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/vioapic.c b/xen/arch/x86/hvm/vioapic.c
index d3c681b..0b343bd 100644
--- a/xen/arch/x86/hvm/vioapic.c
+++ b/xen/arch/x86/hvm/vioapic.c
@@ -238,10 +238,11 @@ static int vioapic_write(
 
 static int vioapic_range(struct vcpu *v, unsigned long addr)
 {
-    struct hvm_hw_vioapic *vioapic = domain_vioapic(v->domain);
+    struct hvm_vioapic *vioapic = v->domain->arch.hvm_domain.vioapic;
+    struct hvm_hw_vioapic *hwapic = domain_vioapic(v->domain);
 
-    return ((addr >= vioapic->base_address &&
-             (addr < vioapic->base_address + VIOAPIC_MEM_LENGTH)));
+    return (vioapic && (addr >= hwapic->base_address &&
+                        (addr < hwapic->base_address + VIOAPIC_MEM_LENGTH)));
 }
 
 const struct hvm_mmio_handler vioapic_mmio_handler = {
-- 
1.8.3.1