Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] iommu/amd: fix interrupt remapping for avic
To:     Maxim Levitsky <mlevitsk@redhat.com>, linux-kernel@vger.kernel.org
Cc:     "open list:AMD IOMMU (AMD-VI)" <iommu@lists.linux-foundation.org>,
        Joao Martins <joao.m.martins@oracle.com>,
        Joerg Roedel <joro@8bytes.org>
References: <20200913124211.6419-1-mlevitsk@redhat.com>
From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-ID: <60856c61-062b-8d92-e565-38bd00855228@amd.com>
Date:   Mon, 14 Sep 2020 21:48:46 +0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101
 Thunderbird/68.12.0
In-Reply-To: <20200913124211.6419-1-mlevitsk@redhat.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from [10.252.73.101] (165.204.80.7) by KL1PR0601CA0021.apcprd06.prod.outlook.com (2603:1096:802:1::31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3370.16 via Frontend Transport; Mon, 14 Sep 2020 14:48:54 +0000
X-Originating-IP: [165.204.80.7]
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-HT: Tenant
X-MS-Office365-Filtering-Correlation-Id: 8d5fc6c0-5372-40a3-af67-08d858bd4e5e
X-MS-TrafficTypeDiagnostic: DM6PR12MB3273:
X-Microsoft-Antispam-PRVS: <DM6PR12MB32736CB48CFA4E166711B456F3230@DM6PR12MB3273.namprd12.prod.outlook.com>
X-MS-Oob-TLC-OOBClassifiers: OLM:3513;
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: eFnf8NMDGW3aXy2YrSqiybCjn74yyWtwFFPonT2f4d79+26tlMy09IgSUI5Rf/s7+e7qqSnRCCwgKYb7+BDttCYLEL+SZSjfGVCUNtWekrZ4zuKWLQeZ6vx7Q/horRCj7QBaXU2osta+IK7Lgcv/5qvtIlJdoGwbdCuprH9JJ7sWHHHCJPxAzARYwnlp4ON65CAsyljRornjM4tZZBjXBSV6utEDR9TVlkxAJfHDpCqpuc0W46IV5QlpT+RoKUkOmODm5LR4oJejnc8/ElbEyluT2OaNbd1a0MV21qTdZRrj7TFnHeQHHjNxV2cHXVL5UocfkASP0lSm66tvl/e3/pYN3DIIE34mrHZS9n4+G5WwNowZUj5GyRnERLnLFZx2
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM5PR12MB1163.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(39860400002)(366004)(376002)(396003)(346002)(136003)(31696002)(6486002)(16526019)(5660300002)(186003)(26005)(478600001)(956004)(16576012)(316002)(2616005)(52116002)(44832011)(53546011)(54906003)(83380400001)(2906002)(4326008)(8676002)(6666004)(31686004)(8936002)(36756003)(86362001)(66946007)(66556008)(66476007)(43740500002);DIR:OUT;SFP:1101;
X-MS-Exchange-AntiSpam-MessageData: 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
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 8d5fc6c0-5372-40a3-af67-08d858bd4e5e
X-MS-Exchange-CrossTenant-AuthSource: DM5PR12MB1163.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Sep 2020 14:48:56.1995
 (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: ZIZ8/LY531MW61ePPP0jEGpF9lKyqnIkItAeWomiq0WnZzrjSynfZRBUBj8Z2yB0/e6GpMc3ct1ZQfd/PIZJGA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB3273
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Maxim,

On 9/13/2020 7:42 PM, Maxim Levitsky wrote:
> Commit e52d58d54a32 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE")
> accidentally removed an assumption that modify_irte_ga always set the valid bit
> and amd_iommu_activate_guest_mode relied on that.
> 
> Side effect of this is that on my machine, VFIO based VMs with AVIC enabled
> would eventually crash and show IOMMU errors like that:
> 
> AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0055 address=0xfffffffdf8000000 flags=0x0008]
> 
> Fixes: e52d58d54a321 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE")
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>   drivers/iommu/amd/iommu.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index 07ae8b93887e5..aff4cc1869356 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -3853,6 +3853,7 @@ int amd_iommu_activate_guest_mode(void *data)
>   	entry->hi.fields.ga_root_ptr       = ir_data->ga_root_ptr;
>   	entry->hi.fields.vector            = ir_data->ga_vector;
>   	entry->lo.fields_vapic.ga_tag      = ir_data->ga_tag;
> +	entry->lo.fields_remap.valid = 1;
>   
>   	return modify_irte_ga(ir_data->irq_2_irte.devid,
>   			      ir_data->irq_2_irte.index, entry, ir_data);
> 

Could you please try with the following patch instead?

--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -3840,14 +3840,18 @@ int amd_iommu_activate_guest_mode(void *data)
  {
         struct amd_ir_data *ir_data = (struct amd_ir_data *)data;
         struct irte_ga *entry = (struct irte_ga *) ir_data->entry;
+       u64 valid;

         if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) ||
             !entry || entry->lo.fields_vapic.guest_mode)
                 return 0;

+       valid = entry->lo.fields_vapic.valid;
+
         entry->lo.val = 0;
         entry->hi.val = 0;

+       entry->lo.fields_vapic.valid       = valid;
         entry->lo.fields_vapic.guest_mode  = 1;
         entry->lo.fields_vapic.ga_log_intr = 1;
         entry->hi.fields.ga_root_ptr       = ir_data->ga_root_ptr;
@@ -3864,12 +3868,14 @@ int amd_iommu_deactivate_guest_mode(void *data)
         struct amd_ir_data *ir_data = (struct amd_ir_data *)data;
         struct irte_ga *entry = (struct irte_ga *) ir_data->entry;
         struct irq_cfg *cfg = ir_data->cfg;
-       u64 valid = entry->lo.fields_remap.valid;
+       u64 valid;

         if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) ||
             !entry || !entry->lo.fields_vapic.guest_mode)
                 return 0;

+       valid = entry->lo.fields_remap.valid;
+
         entry->lo.val = 0;
         entry->hi.val = 0;
--

Thanks,
Suravee