From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934157AbbA1EVM (ORCPT ); Tue, 27 Jan 2015 23:21:12 -0500 Received: from mail.kernel.org ([198.145.29.136]:39437 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933192AbbA1EVG (ORCPT ); Tue, 27 Jan 2015 23:21:06 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andy Honig , Paolo Bonzini , Zefan Li Subject: [PATCH 3.4 078/177] KVM: x86: Prevent host from panicking on shared MSR writes. Date: Wed, 28 Jan 2015 12:08:42 +0800 Message-Id: <1422418236-12852-155-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422418050-12581-1-git-send-email-lizf@kernel.org> References: <1422418050-12581-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Honig 3.4.106-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 8b3c3104c3f4f706e99365c3e0d2aa61b95f969f upstream. The previous patch blocked invalid writes directly when the MSR is written. As a precaution, prevent future similar mistakes by gracefulling handle GPs caused by writes to shared MSRs. Signed-off-by: Andrew Honig [Remove parts obsoleted by Nadav's patch. - Paolo] Signed-off-by: Paolo Bonzini [lizf: Backported to 3.4: - adjust context - s/wrmsrl_safe/checking_wrmsrl/] Signed-off-by: Zefan Li --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/vmx.c | 7 +++++-- arch/x86/kvm/x86.c | 11 ++++++++--- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c1e0ef0..4f78757 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -954,7 +954,7 @@ int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu); int kvm_cpu_get_interrupt(struct kvm_vcpu *v); void kvm_define_shared_msr(unsigned index, u32 msr); -void kvm_set_shared_msr(unsigned index, u64 val, u64 mask); +int kvm_set_shared_msr(unsigned index, u64 val, u64 mask); bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip); diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 7806435..338f478 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2210,12 +2210,15 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) break; msr = find_msr_entry(vmx, msr_index); if (msr) { + u64 old_msr_data = msr->data; msr->data = data; if (msr - vmx->guest_msrs < vmx->save_nmsrs) { preempt_disable(); - kvm_set_shared_msr(msr->index, msr->data, - msr->mask); + ret = kvm_set_shared_msr(msr->index, msr->data, + msr->mask); preempt_enable(); + if (ret) + msr->data = old_msr_data; } break; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 51cc661..318a245 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -220,19 +220,24 @@ static void kvm_shared_msr_cpu_online(void) shared_msr_update(i, shared_msrs_global.msrs[i]); } -void kvm_set_shared_msr(unsigned slot, u64 value, u64 mask) +int kvm_set_shared_msr(unsigned slot, u64 value, u64 mask) { struct kvm_shared_msrs *smsr = &__get_cpu_var(shared_msrs); + int err; if (((value ^ smsr->values[slot].curr) & mask) == 0) - return; + return 0; smsr->values[slot].curr = value; - wrmsrl(shared_msrs_global.msrs[slot], value); + err = checking_wrmsrl(shared_msrs_global.msrs[slot], value); + if (err) + return 1; + if (!smsr->registered) { smsr->urn.on_user_return = kvm_on_user_return; user_return_notifier_register(&smsr->urn); smsr->registered = true; } + return 0; } EXPORT_SYMBOL_GPL(kvm_set_shared_msr); -- 1.9.1