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=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 BF05EC433E9 for ; Tue, 2 Feb 2021 16:59:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C01964DB2 for ; Tue, 2 Feb 2021 16:59:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237082AbhBBQ7e (ORCPT ); Tue, 2 Feb 2021 11:59:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236692AbhBBQ4a (ORCPT ); Tue, 2 Feb 2021 11:56:30 -0500 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9C76C0613D6 for ; Tue, 2 Feb 2021 08:55:50 -0800 (PST) Received: by mail-qv1-xf49.google.com with SMTP id h13so15374548qvo.18 for ; Tue, 02 Feb 2021 08:55:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:reply-to:date:message-id:mime-version:subject:from:to:cc; bh=4vQ54utvl5pYCDc2RGTnD5j/mRhLCg57OZJNdDMaGn4=; b=T0Z94yO1HKcNcauNpnGQV5NoiEPiLhWX96qMGEYfVm8iVuHq3WK0T3f48qxJmcP/L0 MwxkiWpkpJeDBnPwg5tv2PaZ/LlFqABU9ikuqKHO6ZpJZ1dABjxSvbXfpvBwiY098jKA CNgR7EmkK/37q4cQxSJ/Wzz8piqqe6W5zPB2LfP3+00EisR/SeN9et5mgJnEY8jhMstA B6k0pMdDcmaJTtK1pHBQcle76Kvux6qaxNgGuqHtBG/rjy1/n7tu67JKcXlVVU88ukJQ 9X5fhCz2DR2Bk05KxHXzM91nASnHsBSFGRrT76s8M27iZzfK+zXxTuBrWVilTqmbsYK+ Is6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:reply-to:date:message-id:mime-version :subject:from:to:cc; bh=4vQ54utvl5pYCDc2RGTnD5j/mRhLCg57OZJNdDMaGn4=; b=rGVZM1WYD5li9GTsFgQ4QwqYm07AunnBhcHQKBIvzZnEbEJlR0IDV25b+ADYhU0ciz oZzPv37HCJPEVqSlmaEsV4GZGcwl9Jf4a+9mSw+PPoJB8fxoTOv/fW95S/uRKjU2XTnX DvFFWVw6hsUSWIRyowI+Cza7cfjG03qY6tNL2+vjYfQtvukyIT4CWX7kD5GqRKKxNmy7 I+VgGx4bG4QrdFdRIHvWhrHxj9vdOZeBcWLPe6gQo81/eZcCSKL9uFVh7dmUqK1zTtP8 1geEHyVjrzdmi4lt8xJ8xsI8LOwbS7qdUBaXJDvTSU2YNssie8Rx7c0xansUGXatPDBC l3EQ== X-Gm-Message-State: AOAM5333e28XruTY4RVyEXDHE7vVHS4Lx+rA2JNi3lMabvP/YXrXeE3j bpuodXpjN8uh/kLzazdeXr20uTJzxUM= X-Google-Smtp-Source: ABdhPJxkq5VoLdV5TO59a0Enr0ROoksiV8FPHe+Pg9IjpRVfG1jvvaeGXaLW05XydcJXmkuiCs+SgAY6tpo= Sender: "seanjc via sendgmr" X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:e1bc:da69:2e4b:ce97]) (user=seanjc job=sendgmr) by 2002:ad4:4cd0:: with SMTP id i16mr21054987qvz.49.1612284949841; Tue, 02 Feb 2021 08:55:49 -0800 (PST) Reply-To: Sean Christopherson Date: Tue, 2 Feb 2021 08:55:46 -0800 Message-Id: <20210202165546.2390296-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.365.g02bc693789-goog Subject: [PATCH] KVM: x86: Update emulator context mode if SYSENTER xfers to 64-bit mode From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jonny Barker Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Set the emulator context to PROT64 if SYSENTER transitions from 32-bit userspace (compat mode) to a 64-bit kernel, otherwise the RIP update at the end of x86_emulate_insn() will incorrectly truncate the new RIP. Note, this bug is mostly limited to running an Intel virtual CPU model on an AMD physical CPU, as other combinations of virtual and physical CPUs do not trigger full emulation. On Intel CPUs, SYSENTER in compatibility mode is legal, and unconditionally transitions to 64-bit mode. On AMD CPUs, SYSENTER is illegal in compatibility mode and #UDs. If the vCPU is AMD, KVM injects a #UD on SYSENTER in compat mode. If the pCPU is Intel, SYSENTER will execute natively and not trigger #UD->VM-Exit (ignoring guest TLB shenanigans). Fixes: fede8076aab4 ("KVM: x86: handle wrap around 32-bit address space") Cc: stable@vger.kernel.org Signed-off-by: Jonny Barker [sean: wrote changelog] Signed-off-by: Sean Christopherson --- arch/x86/kvm/emulate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 56cae1ff9e3f..66a08322988f 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2879,6 +2879,8 @@ static int em_sysenter(struct x86_emulate_ctxt *ctxt) ops->get_msr(ctxt, MSR_IA32_SYSENTER_ESP, &msr_data); *reg_write(ctxt, VCPU_REGS_RSP) = (efer & EFER_LMA) ? msr_data : (u32)msr_data; + if (efer & EFER_LMA) + ctxt->mode = X86EMUL_MODE_PROT64; return X86EMUL_CONTINUE; } -- 2.30.0.365.g02bc693789-goog