From patchwork Thu Dec 9 18:26:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lewis X-Patchwork-Id: 12668063 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47174C433EF for ; Thu, 9 Dec 2021 18:26:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243304AbhLISaY (ORCPT ); Thu, 9 Dec 2021 13:30:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243219AbhLISaX (ORCPT ); Thu, 9 Dec 2021 13:30:23 -0500 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47933C061746 for ; Thu, 9 Dec 2021 10:26:50 -0800 (PST) Received: by mail-pj1-x1049.google.com with SMTP id jx2-20020a17090b46c200b001a62e9db321so4300955pjb.7 for ; Thu, 09 Dec 2021 10:26:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=9TsHDpZZNunckplei11gkoq/nGaC77zKlswD+hK5oSk=; b=syKJm4QeGqNc92iK1UGh/z+CLDHnR+R2XnkKNVcN16q6EsngXjvOQAJBvjIzcDgy6L EQUFKdBrIV3TiXCYT15N1oMPULZEm3X1cnAUqQpvI6WStV+awjyz3Ggcqye63Q+LXLr7 SgZf/AWjRgY7KsmU6Ioat73RTenpxgdq9OzTOv+jwzOaDumI2xR2SCPbJr3zo3uyP7LC DSSG1x4e0G8oxrA6its9eiaMhEAgfNeqq4Q2ogv2PA/Wjixj7hTYzegWU+aWFobMJ5bf extC9fr8J0Avb5kUtbKEiGzFFZ7arvf2XHFizGjSx6UVHGyYimAjvC/MQAnlgm9+qATq eXPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=9TsHDpZZNunckplei11gkoq/nGaC77zKlswD+hK5oSk=; b=BgcpgZhJPL/tcuKDAHoy6xGRva5nGHBqgE224agLRKz/81XGI3ZL66bB2O59mI6vna 9ZZi+YIeRXmNAUnLU73CkpzSsyu/E2B/2h3LpQoUpHg9csI1vv0ZpvsIisR9nOhaB5Bv 4gBie4QSr1+VCsaR1WhdazNCLnDD1zixvnHxKevAYEHE/fUJtZiIDNvOzG19Qv+kiWrf TRtb7nA1nPpaOeJOET1UBoj0lrgXMWVdjQEaU4BwJ7RcgjSS+FR5NK/eOXka6EsfHfIC ZvOmhEP5XSLZ9u481A8YjiWizXy4luDahn1iJ7dGMuWHwginJaBRoWpLyz1TA2fJFJO5 cw0A== X-Gm-Message-State: AOAM5328QVubmaXK0RDhxwX6WUmBaftLiQ9GmJnwAHxM5oO0Ssk5ig+K duUrvaXlGP0bf8C27NgLPWcG1Yw3uRy/FvfFKQJHKhiRO0AZfZvWc1HVoh8LQPWOlyCIxGYD8pM SoAXRx9U4MgpVKz0Ivx/hXlq7QtBejIYVw/kybn4V7EQFnQxClkkQchZ+agbjTyIKOtHy X-Google-Smtp-Source: ABdhPJySbMXU8f2oqXWYimZh3mCab6broVLgkKQU5/qtRrdiyi7Qn0qyzBD1pC+smdR3bRyIFbxjGi+yTsQKHMQ/ X-Received: from aaronlewis.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2675]) (user=aaronlewis job=sendgmr) by 2002:a63:141d:: with SMTP id u29mr29650444pgl.412.1639074409627; Thu, 09 Dec 2021 10:26:49 -0800 (PST) Date: Thu, 9 Dec 2021 18:26:23 +0000 In-Reply-To: <20211209182624.2316453-1-aaronlewis@google.com> Message-Id: <20211209182624.2316453-3-aaronlewis@google.com> Mime-Version: 1.0 References: <20211209182624.2316453-1-aaronlewis@google.com> X-Mailer: git-send-email 2.34.1.173.g76aa8bc2d0-goog Subject: [kvm-unit-tests PATCH 2/3] x86: Align L2's stacks From: Aaron Lewis To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com, Aaron Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Setting the stack to PAGE_SIZE - 1 sets the stack to being 1-byte aligned, which fails in usermode with alignment checks enabled (ie: with flags cr0.am set and eflags.ac set). This was causing an #AC in usermode.c when preparing to call the callback in run_in_user(). Aligning the stack fixes the issue. For the purposes of fixing the #AC in usermode.c the stack has to be aligned to at least an 8-byte boundary. Setting it to a page aligned boundary ensures any stack alignment requirements are met as x86_64 stacks generally want to be 16-byte aligned. Signed-off-by: Aaron Lewis --- x86/vmx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/x86/vmx.c b/x86/vmx.c index 6dc9a55..44f4861 100644 --- a/x86/vmx.c +++ b/x86/vmx.c @@ -1242,7 +1242,7 @@ static void init_vmcs_guest(void) vmcs_write(GUEST_CR4, guest_cr4); vmcs_write(GUEST_SYSENTER_CS, KERNEL_CS); vmcs_write(GUEST_SYSENTER_ESP, - (u64)(guest_syscall_stack + PAGE_SIZE - 1)); + (u64)(guest_syscall_stack + PAGE_SIZE)); vmcs_write(GUEST_SYSENTER_EIP, (u64)(&entry_sysenter)); vmcs_write(GUEST_DR7, 0); vmcs_write(GUEST_EFER, rdmsr(MSR_EFER)); @@ -1292,7 +1292,7 @@ static void init_vmcs_guest(void) /* 26.3.1.4 */ vmcs_write(GUEST_RIP, (u64)(&guest_entry)); - vmcs_write(GUEST_RSP, (u64)(guest_stack + PAGE_SIZE - 1)); + vmcs_write(GUEST_RSP, (u64)(guest_stack + PAGE_SIZE)); vmcs_write(GUEST_RFLAGS, X86_EFLAGS_FIXED); /* 26.3.1.5 */