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GET /api/patches/2216662/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 2216662,
    "url": "http://patchwork.ozlabs.org/api/patches/2216662/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260327025228.474257-6-zhenzhong.duan@intel.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20260327025228.474257-6-zhenzhong.duan@intel.com>",
    "list_archive_url": null,
    "date": "2026-03-27T02:52:27",
    "name": "[5/5] intel_iommu_accel: teardown FAULTQ resources in bottom half",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "3b149356f05e963bfdf15f9b687398cad2273b72",
    "submitter": {
        "id": 81636,
        "url": "http://patchwork.ozlabs.org/api/people/81636/?format=api",
        "name": "Duan, Zhenzhong",
        "email": "zhenzhong.duan@intel.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260327025228.474257-6-zhenzhong.duan@intel.com/mbox/",
    "series": [
        {
            "id": 497680,
            "url": "http://patchwork.ozlabs.org/api/series/497680/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=497680",
            "date": "2026-03-27T02:52:22",
            "name": "intel_iommu: Enable PRQ support for passthrough device",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/497680/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2216662/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2216662/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
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        ],
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        ],
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            "E=Sophos;i=\"6.23,143,1770624000\"; d=\"scan'208\";a=\"221874395\""
        ],
        "X-ExtLoop1": "1",
        "From": "Zhenzhong Duan <zhenzhong.duan@intel.com>",
        "To": "qemu-devel@nongnu.org",
        "Cc": "alex@shazbot.org, clg@redhat.com, eric.auger@redhat.com, mst@redhat.com,\n jasowang@redhat.com, jgg@nvidia.com, nicolinc@nvidia.com,\n skolothumtho@nvidia.com, joao.m.martins@oracle.com,\n clement.mathieu--drif@bull.com, kevin.tian@intel.com, yi.l.liu@intel.com,\n xudong.hao@intel.com, Zhenzhong Duan <zhenzhong.duan@intel.com>",
        "Subject": "[PATCH 5/5] intel_iommu_accel: teardown FAULTQ resources in bottom\n half",
        "Date": "Thu, 26 Mar 2026 22:52:27 -0400",
        "Message-ID": "<20260327025228.474257-6-zhenzhong.duan@intel.com>",
        "X-Mailer": "git-send-email 2.47.3",
        "In-Reply-To": "<20260327025228.474257-1-zhenzhong.duan@intel.com>",
        "References": "<20260327025228.474257-1-zhenzhong.duan@intel.com>",
        "MIME-Version": "1.0",
        "Content-Transfer-Encoding": "8bit",
        "Received-SPF": "pass client-ip=192.198.163.14;\n envelope-from=zhenzhong.duan@intel.com; helo=mgamail.intel.com",
        "X-Spam_score_int": "-43",
        "X-Spam_score": "-4.4",
        "X-Spam_bar": "----",
        "X-Spam_report": "(-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no",
        "X-Spam_action": "no action",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "qemu development <qemu-devel.nongnu.org>",
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        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"
    },
    "content": "When a pasid entry becomes invalid, we need to release all resources\nallocated for that entry including FAULTQ object and fault_fd.\n\nWe call qemu_set_fd_handler() to detach fault_fd's io_read handler and\nwakes up main thread from poll(), but there could still be a small\nwindow we call iommufd_backend_free_id(fault_id) before poll() exit\nand release fault_id file reference. In this rare case, FAULTQ object\nfree return -EBUSY because opened fault_id file keeps reference of\nFAULTQ object.\n\nTeardown FAULTQ resources in bottom half to ensure poll() has released\nfault_id file reference.\n\nSuggested-by: Shameer Kolothum <skolothumtho@nvidia.com>\nSigned-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>\n---\n hw/i386/intel_iommu_accel.c | 31 +++++++++++++++++++++++++++++--\n 1 file changed, 29 insertions(+), 2 deletions(-)",
    "diff": "diff --git a/hw/i386/intel_iommu_accel.c b/hw/i386/intel_iommu_accel.c\nindex 44af534c55..fdc376c070 100644\n--- a/hw/i386/intel_iommu_accel.c\n+++ b/hw/i386/intel_iommu_accel.c\n@@ -267,16 +267,43 @@ free_faultq:\n     return false;\n }\n \n+typedef struct IOMMUFaultQueue {\n+    IOMMUFDBackend *iommufd;\n+    uint32_t id;\n+    int fd;\n+} IOMMUFaultQueue;\n+\n+static void faultq_teardown_bh(void *opaque)\n+{\n+    IOMMUFaultQueue *fq = opaque;\n+\n+    qemu_set_fd_handler(fq->fd, NULL, NULL, NULL);\n+    close(fq->fd);\n+    iommufd_backend_free_id(fq->iommufd, fq->id);\n+\n+    g_free(fq);\n+}\n+\n+\n static void vtd_destroy_old_fs_faultq(VTDHostIOMMUDevice *vtd_hiod,\n                                       VTDAccelPASIDCacheEntry *vtd_pce)\n {\n+    HostIOMMUDeviceIOMMUFD *idev = HOST_IOMMU_DEVICE_IOMMUFD(vtd_hiod->hiod);\n+\n     if (!vtd_pce->fault_id) {\n         return;\n     }\n \n     vtd_pce->pri_notifier = NULL;\n-    qemu_set_fd_handler(vtd_pce->fault_fd, NULL, NULL, NULL);\n-    vtd_destroy_fs_faultq(vtd_hiod, vtd_pce->fault_id, vtd_pce->fault_fd);\n+\n+    IOMMUFaultQueue *fq = g_malloc(sizeof(IOMMUFaultQueue));\n+    fq->iommufd = idev->iommufd;\n+    fq->fd = vtd_pce->fault_fd;\n+    fq->id = vtd_pce->fault_id;\n+\n+    aio_bh_schedule_oneshot(iohandler_get_aio_context(),\n+                            faultq_teardown_bh, fq);\n+\n     vtd_pce->fault_id = 0;\n     vtd_pce->fault_fd = -1;\n }\n",
    "prefixes": [
        "5/5"
    ]
}