[Xen-devel] [PATCH 2/3] Nested VMX: Clear bit 31 of IA32_VMX_BASIC MSR

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

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

The bit 31 of revision_id will set to 1 if vmcs shadowing enabled. And
according intel SDM, the bit 31 of IA32_VMX_BASIC MSR is always 0. So we
cannot set low 32 bit of IA32_VMX_BASIC to revision_id directly. Must clear
the bit 31 to 0.

Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 2e0b7f7..8571002 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1846,7 +1846,7 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 
*msr_content)
     switch (msr) {
     case MSR_IA32_VMX_BASIC:
         data = (host_data & (~0ul << 32)) |
-               ((v->arch.hvm_vmx.vmcs)->vmcs_revision_id);
+               ((v->arch.hvm_vmx.vmcs)->vmcs_revision_id & ~(1ul << 31));
         break;
     case MSR_IA32_VMX_PINBASED_CTLS:
     case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
-- 
1.7.1


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