From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADCA6C43464 for ; Fri, 18 Sep 2020 02:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79518239D1 for ; Fri, 18 Sep 2020 02:07:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394822; bh=FksXR0rWwjjOH9fBjLhuNrbQn0ueCl1NLji/YoW4JyE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0+p8FS9sQ0FfhB/HIjXC/juzFI4uA8RZ65l+tAJAcyuCtiTNo5moU7g7llMNCJZKB Q+fjD+p/IdK8n+IkBazbgO3u0ZNYjcNWEyP1Pjyr6oOutBLibahjdsCZEKH7hggzpE Qp3bH5V8OKadxpifVe9Xy4+1OpppcpBhZjFPZ0CQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727828AbgIRCHB (ORCPT ); Thu, 17 Sep 2020 22:07:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:55980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727780AbgIRCGe (ORCPT ); Thu, 17 Sep 2020 22:06:34 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 99B9E2388E; Fri, 18 Sep 2020 02:06:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394793; bh=FksXR0rWwjjOH9fBjLhuNrbQn0ueCl1NLji/YoW4JyE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jRIUIfvyjbRovoEekk2ADke8CHKDtwu/TXCFCgH/GWBwkLfdeDQcV6hqHTK+IfCnb t2jYXqukKMIUNKjtJIQRYQQBpcUH95X2LmOC/zVjTH2qPhDn/ubG5IJOGGQWGgVyxz yf1K4AmKlwRH5YjP80Y/WszflEbQavVYnBxSk278= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Paolo Bonzini , Nick Peterson , Sasha Levin , kvm@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 263/330] KVM: x86: handle wrap around 32-bit address space Date: Thu, 17 Sep 2020 22:00:03 -0400 Message-Id: <20200918020110.2063155-263-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020110.2063155-1-sashal@kernel.org> References: <20200918020110.2063155-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo Bonzini [ Upstream commit fede8076aab4c2280c673492f8f7a2e87712e8b4 ] KVM is not handling the case where EIP wraps around the 32-bit address space (that is, outside long mode). This is needed both in vmx.c and in emulate.c. SVM with NRIPS is okay, but it can still print an error to dmesg due to integer overflow. Reported-by: Nick Peterson Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/emulate.c | 2 ++ arch/x86/kvm/svm.c | 3 --- arch/x86/kvm/vmx/vmx.c | 15 ++++++++++++--- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 128d3ad46e965..cc7823e7ef96c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5836,6 +5836,8 @@ writeback: } ctxt->eip = ctxt->_eip; + if (ctxt->mode != X86EMUL_MODE_PROT64) + ctxt->eip = (u32)ctxt->_eip; done: if (rc == X86EMUL_PROPAGATE_FAULT) { diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 3243a80ea32c0..802b5f9ab7446 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -787,9 +787,6 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu) if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP)) return 0; } else { - if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE) - pr_err("%s: ip 0x%lx next 0x%llx\n", - __func__, kvm_rip_read(vcpu), svm->next_rip); kvm_rip_write(vcpu, svm->next_rip); } svm_set_interrupt_shadow(vcpu, 0); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index a071eab3bab74..14b973990d5a8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1541,7 +1541,7 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data) static int skip_emulated_instruction(struct kvm_vcpu *vcpu) { - unsigned long rip; + unsigned long rip, orig_rip; /* * Using VMCS.VM_EXIT_INSTRUCTION_LEN on EPT misconfig depends on @@ -1553,8 +1553,17 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu) */ if (!static_cpu_has(X86_FEATURE_HYPERVISOR) || to_vmx(vcpu)->exit_reason != EXIT_REASON_EPT_MISCONFIG) { - rip = kvm_rip_read(vcpu); - rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN); + orig_rip = kvm_rip_read(vcpu); + rip = orig_rip + vmcs_read32(VM_EXIT_INSTRUCTION_LEN); +#ifdef CONFIG_X86_64 + /* + * We need to mask out the high 32 bits of RIP if not in 64-bit + * mode, but just finding out that we are in 64-bit mode is + * quite expensive. Only do it if there was a carry. + */ + if (unlikely(((rip ^ orig_rip) >> 31) == 3) && !is_64_bit_mode(vcpu)) + rip = (u32)rip; +#endif kvm_rip_write(vcpu, rip); } else { if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP)) -- 2.25.1