Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932389AbbFCMRa (ORCPT ); Wed, 3 Jun 2015 08:17:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57654 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932086AbbFCMQv (ORCPT ); Wed, 3 Jun 2015 08:16:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yang Zhang , Liang Li , Paolo Bonzini Subject: [PATCH 4.0 012/148] kvm/fpu: Enable eager restore kvm FPU for MPX Date: Wed, 3 Jun 2015 21:08:02 +0900 Message-Id: <20150603114205.910602197@linuxfoundation.org> X-Mailer: git-send-email 2.4.2 In-Reply-To: <20150603114205.337615117@linuxfoundation.org> References: <20150603114205.337615117@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3632 Lines: 114 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liang Li commit c447e76b4cabb49ddae8e49c5758f031f35d55fb upstream. The MPX feature requires eager KVM FPU restore support. We have verified that MPX cannot work correctly with the current lazy KVM FPU restore mechanism. Eager KVM FPU restore should be enabled if the MPX feature is exposed to VM. Signed-off-by: Yang Zhang Signed-off-by: Liang Li [Also activate the FPU on AMD processors. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/cpuid.c | 4 ++++ arch/x86/kvm/cpuid.h | 8 ++++++++ arch/x86/kvm/x86.c | 16 ++++++++++++++-- 4 files changed, 27 insertions(+), 2 deletions(-) --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -405,6 +405,7 @@ struct kvm_vcpu_arch { struct kvm_mmu_memory_cache mmu_page_header_cache; struct fpu guest_fpu; + bool eager_fpu; u64 xcr0; u64 guest_supported_xcr0; u32 guest_xstate_size; --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -16,6 +16,8 @@ #include #include #include +#include /* For use_eager_fpu. Ugh! */ +#include /* For use_eager_fpu. Ugh! */ #include #include #include "cpuid.h" @@ -95,6 +97,8 @@ int kvm_update_cpuid(struct kvm_vcpu *vc if (best && (best->eax & (F(XSAVES) | F(XSAVEC)))) best->ebx = xstate_required_size(vcpu->arch.xcr0, true); + vcpu->arch.eager_fpu = guest_cpuid_has_mpx(vcpu); + /* * The existing code assumes virtual address is 48-bit in the canonical * address checks; exit if it is ever changed. --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -111,4 +111,12 @@ static inline bool guest_cpuid_has_rtm(s best = kvm_find_cpuid_entry(vcpu, 7, 0); return best && (best->ebx & bit(X86_FEATURE_RTM)); } + +static inline bool guest_cpuid_has_mpx(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 7, 0); + return best && (best->ebx & bit(X86_FEATURE_MPX)); +} #endif --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6996,7 +6996,9 @@ void kvm_put_guest_fpu(struct kvm_vcpu * fpu_save_init(&vcpu->arch.guest_fpu); __kernel_fpu_end(); ++vcpu->stat.fpu_reload; - kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu); + if (!vcpu->arch.eager_fpu) + kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu); + trace_kvm_fpu(0); } @@ -7012,11 +7014,21 @@ void kvm_arch_vcpu_free(struct kvm_vcpu struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) { + struct kvm_vcpu *vcpu; + if (check_tsc_unstable() && atomic_read(&kvm->online_vcpus) != 0) printk_once(KERN_WARNING "kvm: SMP vm created on host with unstable TSC; " "guest TSC will not be reliable\n"); - return kvm_x86_ops->vcpu_create(kvm, id); + + 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; } int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) -- 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/