Re: [Xen-devel] [PATCH 3/3] X86: MPX IA32_BNDCFGS msr handle

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Jan Beulich wrote:
>>>> On 11.11.13 at 09:40, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
>> From 7886ea2feba430067b169b3404911c1e9d7e88f9 Mon Sep 17 00:00:00
>> 2001 From: Liu Jinsong <jinsong.liu@xxxxxxxxx>
>> Date: Fri, 8 Nov 2013 02:00:37 +0800
>> Subject: [PATCH 3/3] X86: MPX IA32_BNDCFGS msr handle
>> 
>> Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
>> Acked-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>
> 
> This patch clearly is a prereq for enabling support for HVM guests,
> so it can't possibly be the last patch in this series.

So what else do you think we need add to Xudong's patches, except the points 
you have listed?

Thanks,
Jinsong

> 
>> --- a/xen/arch/x86/hvm/vmx/vmcs.c
>> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
>> @@ -269,7 +269,8 @@ static int vmx_init_vmcs_config(void)      }
>> 
>>      min = VM_EXIT_ACK_INTR_ON_EXIT;
>> -    opt = VM_EXIT_SAVE_GUEST_PAT | VM_EXIT_LOAD_HOST_PAT;
>> +    opt = VM_EXIT_SAVE_GUEST_PAT | VM_EXIT_LOAD_HOST_PAT |
>> +          VM_EXIT_CLEAR_BNDCFGS;
>>      min |= VM_EXIT_IA32E_MODE;
>>      _vmx_vmexit_control = adjust_vmx_controls(
>>          "VMExit Control", min, opt, MSR_IA32_VMX_EXIT_CTLS,
>> &mismatch); @@ -283,7 +284,7 @@ static int vmx_init_vmcs_config(void)
>>          _vmx_pin_based_exec_control  &= ~
>> PIN_BASED_POSTED_INTERRUPT; 
>> 
>>      min = 0;
>> -    opt = VM_ENTRY_LOAD_GUEST_PAT;
>> +    opt = VM_ENTRY_LOAD_GUEST_PAT | VM_ENTRY_LOAD_BNDCFGS;
>>      _vmx_vmentry_control = adjust_vmx_controls(
>>          "VMEntry Control", min, opt, MSR_IA32_VMX_ENTRY_CTLS,
>> &mismatch); 
>> 
> 
> So up to here the feature is treated as optional. But then no
> further consequences result when it's unavailable (in particular
> in the [hypothetical?] case where the VMX aspects and the CPUID
> one disagree. This needs to be handled properly.
> 
> Jan


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