Re: [PATCH] KVM: x86: fix eflags state following processor init/reset

2015-11-10 Thread Wanpeng Li 
2015-11-03 18:47 GMT+08:00 Paolo Bonzini :
>
>
> On 28/10/2015 09:10, Nadav Amit wrote:
>> Here are my 5 cents. Note that vmx_vcpu_reset calls:
>>
>>   vmcs_writel(GUEST_RFLAGS, 0x02);
>>
>> (And the RFLAGS value is not cached by KVM, so no consistency problem should
>> occur.)
>>
>> You may want to change the value into constant or call a wrapper function
>> for setting RFLAGS, but I don’t see something broken in the functionality.
>
> I agree.  Wanpeng, if this is just a cleanup, can you send v2 that
> removes or modifies the existing call to vmcs_writel?  If there is a
> bug, can you write a unit test for it?  It should be possible to test
> for the problem using INIT+SIPI on an AP.

You are right, I write a INIT+SIPI kvm-unit-test and didn't trigger
any bug. Please ignore the patch.

Regards,
Wanpeng Li
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Re: [PATCH] KVM: x86: fix eflags state following processor init/reset

2015-11-03 Thread Paolo Bonzini 


On 28/10/2015 09:10, Nadav Amit wrote:
> Here are my 5 cents. Note that vmx_vcpu_reset calls:
> 
>   vmcs_writel(GUEST_RFLAGS, 0x02);
> 
> (And the RFLAGS value is not cached by KVM, so no consistency problem should
> occur.)
> 
> You may want to change the value into constant or call a wrapper function
> for setting RFLAGS, but I don’t see something broken in the functionality.

I agree.  Wanpeng, if this is just a cleanup, can you send v2 that
removes or modifies the existing call to vmcs_writel?  If there is a
bug, can you write a unit test for it?  It should be possible to test
for the problem using INIT+SIPI on an AP.

Thanks,

Paolo

> Regards,
> Nadav
> 
> Wanpeng Li  wrote:
> 
>> Ping, :-)
>> On 10/21/15 2:28 PM, Wanpeng Li wrote:
>>> Reference SDM 3.4.3:
>>>
>>> Following initialization of the processor (either by asserting the
>>> RESET pin or the INIT pin), the state of the EFLAGS register is
>>> 0002H.
>>>
>>> However, the eflags fixed bit is not set and other bits are also not
>>> cleared during the init/reset in kvm.
>>>
>>> This patch fix it by set eflags register to 0002H following
>>> initialization of the processor.
>>>
>>> Signed-off-by: Wanpeng Li 
>>> ---
>>>  arch/x86/kvm/vmx.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>>> index b680c2e..326f6ea 100644
>>> --- a/arch/x86/kvm/vmx.c
>>> +++ b/arch/x86/kvm/vmx.c
>>> @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, 
>>> bool init_event)
>>> vmx_set_efer(vcpu, 0);
>>> vmx_fpu_activate(vcpu);
>>> update_exception_bitmap(vcpu);
>>> +   vmx_set_rflags(vcpu, X86_EFLAGS_FIXED);
>>> vpid_sync_context(vmx->vpid);
>>>  }
>>
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> 
> 
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Re: [PATCH] KVM: x86: fix eflags state following processor init/reset

2015-10-28 Thread Nadav Amit 
Here are my 5 cents. Note that vmx_vcpu_reset calls:

vmcs_writel(GUEST_RFLAGS, 0x02);

(And the RFLAGS value is not cached by KVM, so no consistency problem should
occur.)

You may want to change the value into constant or call a wrapper function
for setting RFLAGS, but I don’t see something broken in the functionality.

Regards,
Nadav

Wanpeng Li  wrote:

> Ping, :-)
> On 10/21/15 2:28 PM, Wanpeng Li wrote:
>> Reference SDM 3.4.3:
>> 
>> Following initialization of the processor (either by asserting the
>> RESET pin or the INIT pin), the state of the EFLAGS register is
>> 0002H.
>> 
>> However, the eflags fixed bit is not set and other bits are also not
>> cleared during the init/reset in kvm.
>> 
>> This patch fix it by set eflags register to 0002H following
>> initialization of the processor.
>> 
>> Signed-off-by: Wanpeng Li 
>> ---
>>  arch/x86/kvm/vmx.c | 1 +
>>  1 file changed, 1 insertion(+)
>> 
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index b680c2e..326f6ea 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool 
>> init_event)
>>  vmx_set_efer(vcpu, 0);
>>  vmx_fpu_activate(vcpu);
>>  update_exception_bitmap(vcpu);
>> +vmx_set_rflags(vcpu, X86_EFLAGS_FIXED);
>>  vpid_sync_context(vmx->vpid);
>>  }
> 
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Re: [PATCH] KVM: x86: fix eflags state following processor init/reset

2015-10-27 Thread Wanpeng Li 

Ping, :-)
On 10/21/15 2:28 PM, Wanpeng Li wrote:

Reference SDM 3.4.3:

Following initialization of the processor (either by asserting the
RESET pin or the INIT pin), the state of the EFLAGS register is
0002H.

However, the eflags fixed bit is not set and other bits are also not
cleared during the init/reset in kvm.

This patch fix it by set eflags register to 0002H following
initialization of the processor.

Signed-off-by: Wanpeng Li 
---
  arch/x86/kvm/vmx.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b680c2e..326f6ea 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool 
init_event)
vmx_set_efer(vcpu, 0);
vmx_fpu_activate(vcpu);
update_exception_bitmap(vcpu);
+   vmx_set_rflags(vcpu, X86_EFLAGS_FIXED);
  
  	vpid_sync_context(vmx->vpid);

  }


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[PATCH] KVM: x86: fix eflags state following processor init/reset

2015-10-21 Thread Wanpeng Li 
Reference SDM 3.4.3:

Following initialization of the processor (either by asserting the 
RESET pin or the INIT pin), the state of the EFLAGS register is 
0002H.

However, the eflags fixed bit is not set and other bits are also not 
cleared during the init/reset in kvm.

This patch fix it by set eflags register to 0002H following 
initialization of the processor.

Signed-off-by: Wanpeng Li 
---
 arch/x86/kvm/vmx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b680c2e..326f6ea 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool 
init_event)
vmx_set_efer(vcpu, 0);
vmx_fpu_activate(vcpu);
update_exception_bitmap(vcpu);
+   vmx_set_rflags(vcpu, X86_EFLAGS_FIXED);
 
vpid_sync_context(vmx->vpid);
 }
-- 
1.9.1

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