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: <8b58ba70-714b-ac53-4598-a6c9f270a0be@amd.com>
Date:   Wed, 29 Jun 2022 18:50:46 +0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.10.0
Subject: Re: [PATCH v3 1/7] iommu/amd: Warn when found inconsistency EFR mask
Content-Language: en-US
To:     Joerg Roedel <joro@8bytes.org>
Cc:     linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        robin.murphy@arm.com, ashish.kalra@amd.com, vasant.hegde@amd.com,
        thomas.lendacky@amd.com
References: <20220622171131.11870-1-suravee.suthikulpanit@amd.com>
 <20220622171131.11870-2-suravee.suthikulpanit@amd.com>
 <YrQizrI5lR3ki37B@8bytes.org>
From:   "Suthikulpanit, Suravee" <suravee.suthikulpanit@amd.com>
In-Reply-To: <YrQizrI5lR3ki37B@8bytes.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?K2NmbWk5TzBOMExHek9wLzhHdTBGLzVGbTdhaEdPeElEVjRVeWxmTUN3dTFr?=
 =?utf-8?B?WTB3Nm5vcVhQL0FZYUNrQ0EzRVBYbTdaa2NwbUtJTlV1UDdqM3krUkRVUmE3?=
 =?utf-8?B?VTM5bDQ2ZG0wdEVIb0I3U1Q5TmhtYXYzY080bktKL3Y2eCtvVi9ZdU1KVXc0?=
 =?utf-8?B?bnJsTitQNWIvekZlNFZGUmZpb0JaT1ZQeWtlbnhqQVB3Z1hWRmk2RmFVN2Vu?=
 =?utf-8?B?WHg2d2p6VkNjMDk4TVJkUk4wYWJGYUdZTDdrQm1yNTc2Nk5tQUtuWW56VXNG?=
 =?utf-8?B?VWZsU1VabmdIQW1VSjJHaVlJMVRpZ2o1R1c1R21YQzNMQjBIdkVWL3lJVnVy?=
 =?utf-8?B?ZGtaMms3ekhuOFFTWHI3aS9FNkpnZ0JCREMxNVJNa2JKdGc2alZVN2c1aXFB?=
 =?utf-8?B?ZFJtQ2F1K3JxOVhYRjRxamZYRUw1RUpLNnhDaXUyTSszOStlT09vRHNDZktN?=
 =?utf-8?B?cndQdjdYbWdKSFFPWmEwOFlqZTlzZ1k4VFNVaUw1dWZOSGhJQUhubVkwV0VL?=
 =?utf-8?B?U2l3MHhBa3g2clFJcGpPdjFtM0VkVUV4ZVlrdm1TdnRkK3dudGkrcnpOZmwv?=
 =?utf-8?B?cXhHbkJ4SzdmZ3NQMEdPZGFpdEt5eTRwdnVNL1RPVnZHUWdnMnNtVStlWmx1?=
 =?utf-8?B?OFdXbnRRVmVvV21xRkhGVDFBRlZwSVJ6WmlHLytwTDNkVFRFRTlyQ0YzSXdv?=
 =?utf-8?B?NFJ1UlVvNG5ZTVhQM01YQlh0cjIrRzdmUXFXSXpRWkRnWGlDajRFbFZhdUY4?=
 =?utf-8?B?TCtFL2tzVWJEMldoUjdKRzEvRWVPSzA1b2swd1o1Ylh6OVY5TjdtUkZjNVZD?=
 =?utf-8?B?UmpmS2cvMUFkK2dYTEdQRmRTRGxzN1lGelluOGFhZ1o0Qzl5Z3d0N2VNbXJI?=
 =?utf-8?B?MzlBYzc0eDBycGZqclB0bmUyU2RiVHNJYmJIT1dGMGtxREFaVE5rTC9jaUlJ?=
 =?utf-8?B?ek83aFgxQSsrYkh3ODlmVDR2SFhUMkpocS9iWnE5ajFIMy9ncWdOeldRVytM?=
 =?utf-8?B?TGtydXBRWnlZVkQrYnN4SnV5cFY1YS9vY0U5c2VkSWJuOGRmUkRxQW5YNVp0?=
 =?utf-8?B?VmhhMTBiTnZkQXJiS1lxU2NJaklTajhSUXRGOSs5aThRa2NuRFAzbnRoMnFr?=
 =?utf-8?B?Nkt2WGNkRWxvZkJCMnlTRnNOUS84Q0h0eEp5eE0wY1ZFallaK21PRzZUOHE0?=
 =?utf-8?B?WitKRlc5cDVhYTVwTWx5VUllRFZXREhTY1l0K0YwUDhIdnZXdVI2SDNNSExj?=
 =?utf-8?B?aXFjSXExMHJ3OGo2YUVHY01VN3N0bWVYTzZiOTU1MzdUcVJhTHpVVnpPcXhl?=
 =?utf-8?B?RUo1bmVQcVgycXg1aVp0OXBSa1daV29lWk5kR1gwQkdiYi9kb1M0UDZ5TWJE?=
 =?utf-8?B?R3F3NkIvdERYdjVWUXA2OFIyYlhvVW9zUzZoZUNidUxYUytTb1RsbjA5QWx1?=
 =?utf-8?B?K2RhZWF3N2ZvcnNuVlRrUXRLSmx6aUZHaGFmZ083K28yYk40dWg5cDZJczJz?=
 =?utf-8?B?anBOOVVyYnhzTnF4VHMrWXNRa2xIUHZNdkw0OTRvNFBoczBuYUZCUkJWQndI?=
 =?utf-8?B?RndHSDdQU0o1UG1CRDJKSGJ6V0FDZXZmU2ljaGtHQTUxQ2xoWFcrQ0pQRVJ2?=
 =?utf-8?B?K0dFejlNQ2pvQUcxUEIySEVhZWUwTG04KzBPZ3loemdhT0xkVyt5RGZvUGtq?=
 =?utf-8?B?djJBOVZGbmpjNDNjU2daa0ZjYmZ6L2FZM0RLczF3ZlYvRkNmYnVNZ3JnZTc5?=
 =?utf-8?B?ZHZ2ZFFhckNtUEQ1SkRCcEJrZ2JVeWtNUGphOU5BK3R2QWFvdldoNmFGT2RV?=
 =?utf-8?B?bXBGNmFkSHNJRDNnM3IxeW94RUFySHJVcXZSTWtOcHFaRlpYdnpKZXc2K2M3?=
 =?utf-8?B?a3VMVWxlSmpNUFA5WjUwK3NySVhwT2xBTUxiMVR4ZGtURk9SME9kcFRWU2VZ?=
 =?utf-8?B?N2U3dUdnRGh2bTk0RkpsTUlvYkcvbnNUVktxNFhheVB2VlRtMS9UZ3UxK1dh?=
 =?utf-8?B?R2xYeFdaYmRwdytjaTZneVhSYyttazJza2t6OFBhYmtrOHdKK0p4R3l2eUgz?=
 =?utf-8?B?WmhuNENwOEtBRFNpOG5OK1dENEQreWg3azZEUEY0VUFTYlNSRXJmS1hnZjh1?=
 =?utf-8?Q?UqdOuJpIW/rx4uq2DtcRJ5TIt?=
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: f56f3285-6a4f-41bd-dafa-08da59c59fbc
X-MS-Exchange-CrossTenant-AuthSource: DM8PR12MB5445.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jun 2022 11:50:55.3960
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 6ekI/HP2JcABwN6/jxVOKecExrThPC0rjtreRTDY8u1c6hXs6TVkgUD7JwmacM1saSzv/I2RaN7RMFhCHd0pLA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4503
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 6/23/2022 3:22 PM, Joerg Roedel wrote:
> On Wed, Jun 22, 2022 at 12:11:25PM -0500, Suravee Suthikulpanit wrote:
>>   #ifdef CONFIG_IRQ_REMAP
>> +/*
>> + * Iterate through all the IOMMUs to verify if the specified
>> + * EFR bitmask of IOMMU feature are set.
>> + * Warn and return false if found inconsistency.
>> + */
>>   static bool check_feature_on_all_iommus(u64 mask)
>>   {
>>   	bool ret = false;
>>   	struct amd_iommu *iommu;
>>   
>>   	for_each_iommu(iommu) {
>> -		ret = iommu_feature(iommu, mask);
>> -		if (!ret)
>> +		bool tmp = iommu_feature(iommu, mask);
>> +
>> +		if ((ret != tmp) &&
>> +		    !list_is_first(&iommu->list, &amd_iommu_list)) {
>> +			pr_err(FW_BUG "Found inconsistent EFR mask (%#llx) on iommu%d (%04x:%02x:%02x.%01x).\n",
>> +			       mask, iommu->index, iommu->pci_seg->id, PCI_BUS_NUM(iommu->devid),
>> +			       PCI_SLOT(iommu->devid), PCI_FUNC(iommu->devid));
>>   			return false;
>> +		}
>> +		ret = tmp;
> 
> It is better to implement this by introducing a global feature mask,
> which represents the minial set of features supported by any IOMMU in
> the system.
> 
> The warning is then something like:
> 
> 	if ((global_feature_mask & iommu_features) != global_feature_mask)
> 		pr_warn(...);
> 
> This also makes the global variable to track SNP support obsolete.
> 
> Regards,
> 
> 	Joerg

That's actually better. I'll send out v4 w/ global EFR variable.

Thanks,
Suravee