Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757241Ab3JQOu7 (ORCPT ); Thu, 17 Oct 2013 10:50:59 -0400 Received: from mail-ea0-f179.google.com ([209.85.215.179]:55177 "EHLO mail-ea0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756427Ab3JQOu4 (ORCPT ); Thu, 17 Oct 2013 10:50:56 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: gleb@redhat.com, agraf@suse.de, chao.zhou@intel.com, magnus@boden.cx, kvm@vger.kernel.org Subject: [PATCH 1/2] KVM: x86: fix KVM_SET_XCRS for CPUs that do not support XSAVE Date: Thu, 17 Oct 2013 16:50:46 +0200 Message-Id: <1382021447-20216-2-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1382021447-20216-1-git-send-email-pbonzini@redhat.com> References: <1382021447-20216-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1800 Lines: 54 The KVM_SET_XCRS ioctl must accept anything that KVM_GET_XCRS could return. XCR0's bit 0 is always 1 in real processors with XSAVE, and KVM_GET_XCRS will always leave bit 0 set even if the emulated processor does not have XSAVE. So, KVM_SET_XCRS must ignore that bit when checking for attempts to enable unsupported save states. Signed-off-by: Paolo Bonzini --- Introduced between v2 and v3, when I stopped hardcoding XSTATE_FPSSE in guest_supported_xcr0. arch/x86/kvm/x86.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c951c71..f4e1391 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -577,6 +577,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr) { u64 xcr0; + u64 valid_bits; /* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */ if (index != XCR_XFEATURE_ENABLED_MASK) @@ -586,8 +587,16 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr) return 1; if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE)) return 1; - if (xcr0 & ~vcpu->arch.guest_supported_xcr0) + + /* + * Do not allow the guest to set bits that we do not support + * saving. However, xcr0 bit 0 is always set, even if the + * emulated CPU does not support XSAVE (see fx_init). + */ + valid_bits = vcpu->arch.guest_supported_xcr0 | XSTATE_FP; + if (xcr0 & ~valid_bits) return 1; + kvm_put_guest_xcr0(vcpu); vcpu->arch.xcr0 = xcr0; return 0; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/