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Re: [Xen-devel] [patch] Fix 64bit VMX guest crashing SMP x86_64 dom0

To: "Li, Xin B" <xin.b.li@xxxxxxxxx>
Subject: Re: [Xen-devel] [patch] Fix 64bit VMX guest crashing SMP x86_64 dom0
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 17 Feb 2006 16:35:15 +0000
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On 17 Feb 2006, at 14:43, Li, Xin B wrote:

Fix 64bit VMX guest crashing SMP x86_64 dom0.
We found creating 64bit VMX guest on SMP x86_64 dom0 will crash the
system, and this is introduced when merging with the HVM tree.

Signed-off-by: Yunhong Jiang <yunhong.jiang@xxxxxxxxx>
Signed-off-by: Xin Li <xin.b.li@xxxxxxxxx>

I've applied a more extensive patch that moves the calls to hvm_load_msrs/hvm_restore_msrs into __context_switch(). Hopefully it isn't broken! :-) The changeset is 8871.

Looking at that area of the code, I wonder whether HVM guests need to be calling save_segments() at all, since segment info is automatically saved into the VMCS on vmexit? Even the hvm_save_segments() call seems unnecessary -- all it does is save the contents of the SHADOW_GS MSR, but you keep a shadow copy of that MSR which you update every time the guest writes to the MSR, so surely that is not necessary? Can you try testing x86_64 with the call to save_segments() made conditional on !HVM_DOMAIN(p)?


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