Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <2987196d-a5fd-a756-03f4-e1ddc41b5249@suse.com>
Date:   Tue, 16 Aug 2022 09:48:09 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.12.0
Subject: Re: [PATCH] x86/entry: fix entry_INT80_compat for Xen PV guests
Content-Language: en-US
To:     Juergen Gross <jgross@suse.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, stable@vger.kernel.org,
        xen-devel@lists.xenproject.org, x86@kernel.org,
        linux-kernel@vger.kernel.org
References: <20220816071137.4893-1-jgross@suse.com>
From:   Jan Beulich <jbeulich@suse.com>
In-Reply-To: <20220816071137.4893-1-jgross@suse.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WWl5c1FDYWVoTFRON3FZU1FaRWZWT2JjVWVDaXdWQUtMalRpL0IzckdmWTli?=
 =?utf-8?B?cy9YaEY3bll2T3lDbkI5VUtXbU44d05qaWJhNm1Zd0oyd3JCcmsveVhkelU4?=
 =?utf-8?B?VjR5KzVwQzUweE9WTE1WOUdPQ3RIbWRzbVpWOWxNTVpwdE5nek92eCt0SVdu?=
 =?utf-8?B?THdqam9mMFdVLzR2WjBsVXJSaTY0bjJDQk81M2V6Wm5NQTQrQUNOY0tFL0Zj?=
 =?utf-8?B?emlsUlBWMkgwRlB6cEhXRUFWZldjT1JydmpxK0x2MGtiVXZmQngrT2M1S3hj?=
 =?utf-8?B?T3ZYVWxnZTdBSXlONHhIVm5iM0YwN2dUZFprOVRTa2UvTUNZME1NWTByZDFW?=
 =?utf-8?B?YktJR1hpWHNsV21kSVIrZ2h3ckp4NUIydklCTDE4Z2hmUExQR3ZuaE5ZTGJ2?=
 =?utf-8?B?SWNsNk1jUUlNSFpqOUlqTEZ1WUZ3ZUtqa2E0SzhUVDhpdWdTMDJKZXRqQlNh?=
 =?utf-8?B?MVpVaFQ0T2xSUjI4eTVzV0RUa0M2UU0xandjYU5HV21uaFRUdnltQ2dZWXBE?=
 =?utf-8?B?VXNmOFk2QmszY25aU1l5VGpTV09IY0Q0eTY1MTlTTkJZWXlSeGhrSTZHemNK?=
 =?utf-8?B?d1Z6UHNHUWc1QnltVGgzLzRHR1JkYVB0VXdPZEx5V3ArSUtzdzR0bjZ4NWIr?=
 =?utf-8?B?a2NJb1VQbWRQbjV3ZFdTNzlWNlJEQ1pZbkZqYkh5TzEwNW1pZExZUnpqeXJy?=
 =?utf-8?B?RWU2VnYyT3JhTGtPeDhwaU5LTVdtakJpSnZWNi9LekV0aWdQSnJBOG5PSnVx?=
 =?utf-8?B?ZjB1UitZcllONkRNZjlwUHp4OEJmcE0xWUtlWlhjVkpSRGx0RTl2VnFpZDFu?=
 =?utf-8?B?bHVxa0VTMVJJdXFZb1FpQnVkV1k1YnZ6VHVpUlpyQmZLcVRSY1ByTVliWStQ?=
 =?utf-8?B?YVZrZS9MMVFhYm1vVjlSbmlxWmhQRjBPUEkyRXFGajdRM3NBd1lsS2tUalR2?=
 =?utf-8?B?NzNndzJGRmNPYzBQdGhEb3dwbkJxMkdyNkhZdXV6dkJJbWtmY0JKWmp2V2Uv?=
 =?utf-8?B?UGRqaEM1TWZ2aFJzSTlmNGdUOWp2NmtFNTV2RnBxaXNzTFh1VmxEKzN2K0JI?=
 =?utf-8?B?ZWxxUWRObkw2TzdQb1VKVUZHdHlNN2cxNHNvcWxmY1hkdVUyVW5TV2VLaHBE?=
 =?utf-8?B?TkRTWWFCb3c5ZXJNQ0FrbE9TNzk0L00xUTRTZUFsNEdJVlA0RmV3R09qL3Vt?=
 =?utf-8?B?aExYSnVLcGEwMk5TdGN3RVRhSW9KWWx2TlBZVnRhNjRVT2ZJenBHTE9xU1lC?=
 =?utf-8?B?ZUJ2QURkNTBVdUZBaFl3eU5YUGRHTDJ6WDRHdkx6azcrclRKVk8yL3RGanJV?=
 =?utf-8?B?dENXUkQzM29rOUk2Z0cyWUJ1bnl1U3NlbkZRMTFWZ04vbmt6UFp5bFFqV1Iv?=
 =?utf-8?B?UEtKM05Mc2ZYNTd3ZkFJSWh1dy9FWVNYdWFER0ZBUDFDUUE0L3RnRnRlUy9Z?=
 =?utf-8?B?TGhEY29JSFpRSHRZUm1Zbk9vbFVNblNTdDlCQVRYelNQWE83ZGNPNHVxaWQz?=
 =?utf-8?B?UGlWL05PUWZMZmtId01IMW5Cci8xUllVaUE4MzJaRDBZdDhuWnpxZXVOc2Jk?=
 =?utf-8?B?QUNPSWRReUlHYitUbUVod0U2ZHNaempSaGVjQnJlcU1QRGpoRlJoaEVzTUpD?=
 =?utf-8?B?N1k2UVZib05JdUVMY2NJSWNrN0FKV1ZXVytheU1yNmI1dFJyRDE1NUxEeVp2?=
 =?utf-8?B?Tko1N0pzekovYUY4K3hTYVZWTmxiZ09LODNqUUF5MmxuWTN4c1Y3cFJDcUtS?=
 =?utf-8?B?c1o1ZVhLaGd2WE9wYmd4V3pjcmxvUnJKY1VZcWticEtVWFY1UlgrNUFBcW4z?=
 =?utf-8?B?eE1SZXpXWUlFckNUU0dvK1N3WU0yOStBTG5BSXZkSC9WeDZjNUI1bm9VVXpJ?=
 =?utf-8?B?cWcwUU1uUTl1UUl3bDF4cGZqZzcvZ01yS2ZJS0Z6SzB6VGFtTmRwckdiMUND?=
 =?utf-8?B?WVNDYjNVYkhTak5sUDE3dlR5YjF5dnZ5bGlmbStCTFRSeVYxbmNYSzhrNnUv?=
 =?utf-8?B?NC8rV05VNjVvazJnOVdkNS81b0hoNUxQcXo4QmI4ZEZPb3dVdkxuTUl4SktS?=
 =?utf-8?B?c0VPalhWWVpkdTNDWkp0TlgzZWFyMDgwL0Q0MGFEVk9KT3hCY2x2NjFrM2hE?=
 =?utf-8?Q?3WG9zGFP5ds1/udKxgoMIQqxV?=
X-OriginatorOrg: suse.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 4f8d737e-c708-453a-deb1-08da7f5baad7
X-MS-Exchange-CrossTenant-AuthSource: VE1PR04MB6560.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Aug 2022 07:48:11.2621
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 0pCys0z/aBAMRL2EbX+ymQ7B0RZ63R4syZEWdOT7U8xy27sujV0Fj+GAYKRVXuW0x7le1NQ+UviZXl6O0kBchQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB6PR0402MB2808
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 16.08.2022 09:11, Juergen Gross wrote:
> Commit c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove
> the definition of SWAPGS") missed one use case of SWAPGS in
> entry_INT80_compat. Removing of the SWAPGS macro led to asm just
> using "swapgs", as it is accepting instructions in capital letters,
> too.
> 
> This in turn leads to splats in Xen PV guests like:
> 
> [   36.145223] general protection fault, maybe for address 0x2d: 0000 [#1] PREEMPT SMP NOPTI
> [   36.145794] CPU: 2 PID: 1847 Comm: ld-linux.so.2 Not tainted 5.19.1-1-default #1 openSUSE Tumbleweed f3b44bfb672cdb9f235aff53b57724eba8b9411b
> [   36.146608] Hardware name: HP ProLiant ML350p Gen8, BIOS P72 11/14/2013
> [   36.148126] RIP: e030:entry_INT80_compat+0x3/0xa3
> 
> Fix that by open coding this single instance of the SWAPGS macro.
> 
> Cc: <stable@vger.kernel.org> # 5.19
> Fixes: c89191ce67ef ("x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS")
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>