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
next prev parent reply other threads:[~2014-02-24 11:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-24 10:58 [Qemu-devel] [PATCH v5 3/3] KVM: x86: Enable Intel MPX for guest Liu, Jinsong
2014-02-24 11:13 ` Paolo Bonzini [this message]
2014-02-24 15:37 ` Liu, Jinsong
2014-02-24 16:40 ` Paolo Bonzini
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