linux-kernel - RE: [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest

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Message-ID: <DE8DF0795D48FD4CA783C40EC82923350150F2D0@SHSMSX101.ccr.corp.intel.com>
Date:	Mon, 24 Feb 2014 15:37:18 +0000
From:	"Liu, Jinsong" <jinsong.liu@...el.com>
To:	Paolo Bonzini <pbonzini@...hat.com>,
	"'kvm@...r.kernel.org'" <kvm@...r.kernel.org>,
	"'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>,
	"'qemu-devel@...gnu.org'" <qemu-devel@...gnu.org>
CC:	"'gleb@...hat.com'" <gleb@...hat.com>,
	"'hpa@...or.com'" <hpa@...or.com>
Subject: RE: [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest

Paolo Bonzini wrote:
> Il 24/02/2014 11:58, Liu, Jinsong ha scritto:
>> @@ -599,6 +599,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32
>>  	index, u64 xcr) u64 old_xcr0 = vcpu->arch.xcr0;
>>  	u64 valid_bits;
>> 
>> +	if (!kvm_x86_ops->mpx_supported || !kvm_x86_ops->mpx_supported())
>> +		xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
>> +
>>  	/* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now  */
>>  	if (index != XCR_XFEATURE_ENABLED_MASK)
>>  		return 1;
> 
> This hunk is incorrect, and I can simply drop it when applying.  If
> MPX is not supported, it should not be in the 0Dh CPUID leaf and thus
> in vcpu->arch.guest_supported_xcr0.
> 
> This however relies on userspace passing a "sensible" value of CPUID.
> I'll send a patch to strengthen the computation of
> guest_supported_xcr0. 
> 
> Thanks!
> 
> Paolo

So patch v5 would be applied except you will remove the incorrect hunk, and you will send a patch strengthenning guest_supported_xcr0?

Thanks,
Jinsong--
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