[Xen-devel] [PATCH] Nested VMX: load current_vmcs only when it exists

[Yang Zhang <yang.z.zhang@xxxxxxxxx>]

From: Yang Zhang <yang.z.zhang@xxxxxxxxx>

There may not have valid vmcs on current CPU. So only load it when it exists.

This original fixing is from Edmud <edmund.h.white@xxxxxxxxx>.

Signed-off-by: Edmund H White <edmund.h.white@xxxxxxxxx>
Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index cc84ca2..7564895 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -824,8 +824,12 @@ void virtual_vmcs_enter(void *vvmcs)
 
 void virtual_vmcs_exit(void *vvmcs)
 {
+    struct vmcs_struct *cur = this_cpu(current_vmcs);
+
     __vmpclear(pfn_to_paddr(domain_page_map_to_mfn(vvmcs)));
-    __vmptrld(virt_to_maddr(this_cpu(current_vmcs)));
+    if ( cur )
+        __vmptrld(virt_to_maddr(cur));
+
 }
 
 u64 virtual_vmcs_vmread(void *vvmcs, u32 vmcs_encoding)
-- 
1.7.1


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