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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Liu, Jinsong" <jinsong.liu@intel.com>,
	"'kvm@vger.kernel.org'" <kvm@vger.kernel.org>,
	"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
	"'qemu-devel@nongnu.org'" <qemu-devel@nongnu.org>
Cc: "'gleb@redhat.com'" <gleb@redhat.com>, "'hpa@zytor.com'" <hpa@zytor.com>
Subject: Re: [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest
Date: Mon, 24 Feb 2014 12:13:13 +0100	[thread overview]
Message-ID: <530B2949.4030000@redhat.com> (raw)
In-Reply-To: <DE8DF0795D48FD4CA783C40EC82923350150E43C@SHSMSX101.ccr.corp.intel.com>

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

WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: "Liu, Jinsong" <jinsong.liu@intel.com>,
	"'kvm@vger.kernel.org'" <kvm@vger.kernel.org>,
	"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
	"'qemu-devel@nongnu.org'" <qemu-devel@nongnu.org>
Cc: "'gleb@redhat.com'" <gleb@redhat.com>, "'hpa@zytor.com'" <hpa@zytor.com>
Subject: Re: [Qemu-devel] [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest
Date: Mon, 24 Feb 2014 12:13:13 +0100	[thread overview]
Message-ID: <530B2949.4030000@redhat.com> (raw)
In-Reply-To: <DE8DF0795D48FD4CA783C40EC82923350150E43C@SHSMSX101.ccr.corp.intel.com>

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

  reply	other threads:[~2014-02-24 11:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-24 10:58 [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest Liu, Jinsong
2014-02-24 10:58 ` [Qemu-devel] " Liu, Jinsong
2014-02-24 11:13 ` Paolo Bonzini [this message]
2014-02-24 11:13   ` Paolo Bonzini
2014-02-24 15:37   ` Liu, Jinsong
2014-02-24 15:37     ` [Qemu-devel] " Liu, Jinsong
2014-02-24 16:40     ` Paolo Bonzini
2014-02-24 16:40       ` [Qemu-devel] " Paolo Bonzini

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