[Xen-devel] [PATCH for-4.11] x86/VT-x: Fix determination of EFER.LMA in vmcs_dump_vcpu()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

The LMA setting comes from the entry controls.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>

This arguably wants backporting, so should go into 4.11 at this point.  If
not, I'll queue it in x86-next for the 4.12 dev window.
---
 xen/arch/x86/hvm/vmx/vmcs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 2c5ef36..70c2fb7 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1788,7 +1788,10 @@ void vmcs_dump_vcpu(struct vcpu *v)
     vmentry_ctl = vmr32(VM_ENTRY_CONTROLS),
     vmexit_ctl = vmr32(VM_EXIT_CONTROLS);
     cr4 = vmr(GUEST_CR4);
-    efer = vmr(GUEST_EFER);
+
+    /* EFER.LMA is read as zero, and is loaded from vmentry_ctl on entry. */
+    BUILD_BUG_ON(VM_ENTRY_IA32E_MODE << 1 != EFER_LMA);
+    efer = vmr(GUEST_EFER) | ((vmentry_ctl & VM_ENTRY_IA32E_MODE) << 1);
 
     printk("*** Guest State ***\n");
     printk("CR0: actual=0x%016lx, shadow=0x%016lx, gh_mask=%016lx\n",
-- 
2.1.4


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