From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754868AbbHEWBV (ORCPT ); Wed, 5 Aug 2015 18:01:21 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38684 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932226AbbHEVub (ORCPT ); Wed, 5 Aug 2015 17:50:31 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Paolo Bonzini , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 075/107] KVM: VMX: fix vmwrite to invalid VMCS Date: Wed, 5 Aug 2015 14:49:07 -0700 Message-Id: <1438811379-384-76-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438811379-384-1-git-send-email-kamal@canonical.com> References: <1438811379-384-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= commit 370777daab3f024f1645177039955088e2e9ae73 upstream. fpu_activate is called outside of vcpu_load(), which means it should not touch VMCS, but fpu_activate needs to. Avoid the call by moving it to a point where we know that the guest needs eager FPU and VMCS is loaded. This will get rid of the following trace vmwrite error: reg 6800 value 0 (err 1) [] dump_stack+0x19/0x1b [] vmwrite_error+0x2c/0x2e [kvm_intel] [] vmcs_writel+0x1f/0x30 [kvm_intel] [] vmx_fpu_activate.part.61+0x45/0xb0 [kvm_intel] [] vmx_fpu_activate+0x15/0x20 [kvm_intel] [] kvm_arch_vcpu_create+0x51/0x70 [kvm] [] kvm_vm_ioctl+0x1c1/0x760 [kvm] [] ? handle_mm_fault+0x49a/0xec0 [] do_vfs_ioctl+0x2e5/0x4c0 [] ? file_has_perm+0xae/0xc0 [] SyS_ioctl+0xa1/0xc0 [] system_call_fastpath+0x16/0x1b (Note: we also unconditionally activate FPU in vmx_vcpu_reset(), so the removed code added nothing.) Fixes: c447e76b4cab ("kvm/fpu: Enable eager restore kvm FPU for MPX") Reported-by: Vlastimil Holer Signed-off-by: Radim Krčmář Signed-off-by: Paolo Bonzini Signed-off-by: Kamal Mostafa --- arch/x86/kvm/cpuid.c | 2 ++ arch/x86/kvm/x86.c | 5 ----- 2 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 307f9ec..f3e5375 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -98,6 +98,8 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu) best->ebx = xstate_required_size(vcpu->arch.xcr0, true); vcpu->arch.eager_fpu = guest_cpuid_has_mpx(vcpu); + if (vcpu->arch.eager_fpu) + kvm_x86_ops->fpu_activate(vcpu); /* * The existing code assumes virtual address is 48-bit in the canonical diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4725957..a692f1c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7028,11 +7028,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, vcpu = kvm_x86_ops->vcpu_create(kvm, id); - /* - * Activate fpu unconditionally in case the guest needs eager FPU. It will be - * deactivated soon if it doesn't. - */ - kvm_x86_ops->fpu_activate(vcpu); return vcpu; } -- 1.9.1