From patchwork Fri Feb 17 18:54:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ackerley Tng X-Patchwork-Id: 13145161 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 E6676C636D7 for ; Fri, 17 Feb 2023 18:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229740AbjBQSzK (ORCPT ); Fri, 17 Feb 2023 13:55:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229761AbjBQSzH (ORCPT ); Fri, 17 Feb 2023 13:55:07 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D806E604CC for ; Fri, 17 Feb 2023 10:54:23 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id cq5-20020a056a00330500b00593e2189278so565459pfb.19 for ; Fri, 17 Feb 2023 10:54:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=8XXhCOstGxwm90421DAyoKAej/4Z8mcoi6Wlc8kCjdk=; b=IZ3Z+JoTISDUXkmeFG7QKBn0PDd2RpeSIuii7wzSU5FWqFqD3YKNG+p6S1JpwaSlDh ew0RNKAwlChjbJqhc/GPqNf1onzwQRLDT2pQHAmZ9z13N1rsH4zlD4C/iBORwtcy/7Vs 4LWY2bmqvD+7WPRfYO9LYJkUalQmHeupmZPVU/uJPEn2jjlzI2fHZUFBGgx89uIFNeR8 GQMoxJZ7eN704Skwx87dhfoA1hN1zix01/rqgIEYeAej1Xo5VgUaA7c3+8n9lORAovk5 e/+NnegHzJPw0GpOp+WnX4Iu6JmfT99u3ZWkFj74cIzcI7JpajVc87uUCNr9hx7bRq9F xGug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=8XXhCOstGxwm90421DAyoKAej/4Z8mcoi6Wlc8kCjdk=; b=N82n0xXkiS4N26xprJ42VWeFt9kmXCtYFG+7tVsluVNrx3TrUWN9min0VShW6lZ33S atZQyOqyDBc53P1JN5vBRDFfd6Q9/DVkYlWURerqhaWgB1VbOkH4NXLYBcFJWBC9JOmK f/6YcO29MiZ0mb/tvIchd4QgFxi60QgdGr9pw3FcJODnrPdc1z1o8UUhKwfKWznSaQM+ 9iUayy0J03Hzs7uji5VqSpCv4ZM7zkRCJ6/wXsLHQCDPIwuEiwCxtEG9grfKIGZgQy9t 1gh/TDrhC2BYaPwgppcHPfO5KvLj/LUkGRAbcBSl535qTQOTN1mg+K6XdxJhLXf07f0G SbPQ== X-Gm-Message-State: AO0yUKVN8s/s9BZa/65wsBTckXHwlST+qmn2mcw/BQ5GltB00napjclD cQ+VZc+Ovqw66fLZjq27gZGuMcvy2ZeSAyhT6w== X-Google-Smtp-Source: AK7set+1XTTWB/DeE9M0hPnAQqoc9pw6PJXf/6VSbMIu1YTy+8tDk8uVwsQF3gP8eC2DNG7keUDHRWLwMUFcysx2TA== X-Received: from ackerleytng-cloudtop.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1f5f]) (user=ackerleytng job=sendgmr) by 2002:a62:1d41:0:b0:5a8:dc92:109f with SMTP id d62-20020a621d41000000b005a8dc92109fmr303430pfd.3.1676660059492; Fri, 17 Feb 2023 10:54:19 -0800 (PST) Date: Fri, 17 Feb 2023 18:54:05 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.2.637.g21b0678d19-goog Message-ID: <32866e5d00174697730d6231d2fb81f6b8d98c8a.1676659352.git.ackerleytng@google.com> Subject: [PATCH 1/1] KVM: selftests: Adjust VM's initial stack address to align with SysV ABI spec From: Ackerley Tng To: pbonzini@redhat.com, shuah@kernel.org, seanjc@google.com, dmatlack@google.com, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: erdemaktas@google.com, vannapurve@google.com, sagis@google.com, mail@maciej.szmigiero.name, Ackerley Tng Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Align stack to match calling sequence requirements in section "The Stack Frame" of the System V ABI AMD64 Architecture Processor Supplement, which requires the value (%rsp + 8) to be a multiple of 16 when control is transferred to the function entry point. This is required because GCC is already aligned with the SysV ABI spec, and compiles code resulting in (%rsp + 8) being a multiple of 16 when control is transferred to the function entry point. This fixes guest crashes when compiled guest code contains certain SSE instructions, because thes SSE instructions expect memory references (including those on the stack) to be 16-byte-aligned. Signed-off-by: Ackerley Tng --- This patch is a follow-up from discussions at https://lore.kernel.org/lkml/20230121001542.2472357-9-ackerleytng@google.com/ --- .../selftests/kvm/include/linux/align.h | 15 +++++++++++++++ .../selftests/kvm/lib/x86_64/processor.c | 18 +++++++++++++++++- 2 files changed, 32 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/kvm/include/linux/align.h -- 2.39.2.637.g21b0678d19-goog diff --git a/tools/testing/selftests/kvm/include/linux/align.h b/tools/testing/selftests/kvm/include/linux/align.h new file mode 100644 index 000000000000..2b4acec7b95a --- /dev/null +++ b/tools/testing/selftests/kvm/include/linux/align.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_ALIGN_H +#define _LINUX_ALIGN_H + +#include + +/* @a is a power of 2 value */ +#define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) +#define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a)) +#define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask)) +#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) +#define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a))) +#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) + +#endif /* _LINUX_ALIGN_H */ diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index acfa1d01e7df..09b48ae96fdd 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -5,6 +5,7 @@ * Copyright (C) 2018, Google LLC. */ +#include "linux/align.h" #include "test_util.h" #include "kvm_util.h" #include "processor.h" @@ -569,6 +570,21 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id, DEFAULT_GUEST_STACK_VADDR_MIN, MEM_REGION_DATA); + stack_vaddr += DEFAULT_STACK_PGS * getpagesize(); + + /* + * Align stack to match calling sequence requirements in section "The + * Stack Frame" of the System V ABI AMD64 Architecture Processor + * Supplement, which requires the value (%rsp + 8) to be a multiple of + * 16 when control is transferred to the function entry point. + * + * If this code is ever used to launch a vCPU with 32-bit entry point it + * may need to subtract 4 bytes instead of 8 bytes. + */ + TEST_ASSERT(IS_ALIGNED(stack_vaddr, PAGE_SIZE), + "stack_vaddr must be page aligned for stack adjustment of -8 to work"); + stack_vaddr -= 8; + vcpu = __vm_vcpu_add(vm, vcpu_id); vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid()); vcpu_setup(vm, vcpu); @@ -576,7 +592,7 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id, /* Setup guest general purpose registers */ vcpu_regs_get(vcpu, ®s); regs.rflags = regs.rflags | 0x2; - regs.rsp = stack_vaddr + (DEFAULT_STACK_PGS * getpagesize()); + regs.rsp = stack_vaddr; regs.rip = (unsigned long) guest_code; vcpu_regs_set(vcpu, ®s);