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GET /api/patches/2216049/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 2216049,
    "url": "http://patchwork.ozlabs.org/api/patches/2216049/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260325184259.366-4-alireza.sanaee@huawei.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": "<20260325184259.366-4-alireza.sanaee@huawei.com>",
    "list_archive_url": null,
    "date": "2026-03-25T18:42:51",
    "name": "[3/9] hw/cxl: Hook up tagged host memory backends at runtime for DC extents",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "16635470c2336ddbdfae2701164e795e8b7b26c1",
    "submitter": {
        "id": 90159,
        "url": "http://patchwork.ozlabs.org/api/people/90159/?format=api",
        "name": "Alireza Sanaee",
        "email": "alireza.sanaee@huawei.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260325184259.366-4-alireza.sanaee@huawei.com/mbox/",
    "series": [
        {
            "id": 497484,
            "url": "http://patchwork.ozlabs.org/api/series/497484/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=497484",
            "date": "2026-03-25T18:42:48",
            "name": "Application Specific Tagged Memory Support in CXL Type 3 Devices",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/497484/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2216049/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2216049/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@legolas.ozlabs.org",
        "Authentication-Results": "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)",
        "Received": [
            "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fgwng06NCz1xy3\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 26 Mar 2026 05:45:11 +1100 (AEDT)",
            "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1w5TDp-0003Pb-Sz; Wed, 25 Mar 2026 14:44:53 -0400",
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            "from frasgout.his.huawei.com ([185.176.79.56])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <alireza.sanaee@huawei.com>)\n id 1w5TDl-0007Mw-Dl\n for qemu-devel@nongnu.org; Wed, 25 Mar 2026 14:44:51 -0400",
            "from mail.maildlp.com (unknown [172.18.224.150])\n by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4fgwmW4qzZzHnGjr;\n Thu, 26 Mar 2026 02:44:11 +0800 (CST)",
            "from dubpeml500005.china.huawei.com (unknown [7.214.145.207])\n by mail.maildlp.com (Postfix) with ESMTPS id 7F6D74056B;\n Thu, 26 Mar 2026 02:44:47 +0800 (CST)",
            "from a2303103017.china.huawei.com (10.47.66.203) by\n dubpeml500005.china.huawei.com (7.214.145.207) with Microsoft SMTP Server\n (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id\n 15.2.1544.11; Wed, 25 Mar 2026 18:44:46 +0000"
        ],
        "To": "<qemu-devel@nongnu.org>",
        "CC": "<anisa.su@samsung.com>, <armbru@redhat.com>, <berrange@redhat.com>,\n <eblake@redhat.com>, <jonathan.cameron@huawei.com>,\n <linux-cxl@vger.kernel.org>, <linuxarm@huawei.com>, <lizhijian@fujitsu.com>,\n <mst@redhat.com>, <pbonzini@redhat.com>, <gourry@gourry.net>,\n <nifan.cxl@gmail.com>, <me@linux.beauty>",
        "Subject": "[PATCH 3/9] hw/cxl: Hook up tagged host memory backends at runtime\n for DC extents",
        "Date": "Wed, 25 Mar 2026 18:42:51 +0000",
        "Message-ID": "<20260325184259.366-4-alireza.sanaee@huawei.com>",
        "X-Mailer": "git-send-email 2.51.0.windows.2",
        "In-Reply-To": "<20260325184259.366-1-alireza.sanaee@huawei.com>",
        "References": "<20260325184259.366-1-alireza.sanaee@huawei.com>",
        "MIME-Version": "1.0",
        "Content-Transfer-Encoding": "8bit",
        "Content-Type": "text/plain",
        "X-Originating-IP": "[10.47.66.203]",
        "X-ClientProxiedBy": "lhrpeml500011.china.huawei.com (7.191.174.215) To\n dubpeml500005.china.huawei.com (7.214.145.207)",
        "Received-SPF": "pass client-ip=185.176.79.56;\n envelope-from=alireza.sanaee@huawei.com; helo=frasgout.his.huawei.com",
        "X-Spam_score_int": "-41",
        "X-Spam_score": "-4.2",
        "X-Spam_bar": "----",
        "X-Spam_report": "(-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3,\n RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_NONE=0.001, 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>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Reply-to": "Alireza Sanaee <alireza.sanaee@huawei.com>",
        "From": "Alireza Sanaee via qemu development <qemu-devel@nongnu.org>",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"
    },
    "content": "When a type3 device is created with dc-regions-total-size instead of an\ninitial volatile-dc-memdev, prescriptive DC add requests need a way to name\nthe backend to attach to the accepted extent.\n\nTeach the QMP and mailbox paths to carry that tag through the lazy\ndynamic-capacity flow. In the add path, resolve the tag to a generic host\nmemory backend, reject reuse of an already-mapped backend, and verify that\nthe backend size matches the requested extent.\n\nStore the selected backend metadata on the pending extent so a later patch\ncan bind the accepted extent to the chosen backend when the host\nacknowledges the request.\n\nSigned-off-by: Alireza Sanaee <alireza.sanaee@huawei.com>\n---\n hw/cxl/cxl-mailbox-utils.c |  8 ----\n hw/mem/cxl_type3.c         | 77 ++++++++++++++++++++++++++++++++------\n 2 files changed, 65 insertions(+), 20 deletions(-)",
    "diff": "diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c\nindex e6e136cf44..c83b5f90d4 100644\n--- a/hw/cxl/cxl-mailbox-utils.c\n+++ b/hw/cxl/cxl-mailbox-utils.c\n@@ -4270,10 +4270,6 @@ static CXLRetCode cmd_fm_initiate_dc_add(const struct cxl_cmd *cmd,\n     CXLType3Dev *ct3d = CXL_TYPE3(cci->d);\n     int i, rc;\n \n-    if (ct3d->dc.total_capacity_cmd) {\n-        return CXL_MBOX_UNSUPPORTED;\n-    }\n-\n     switch (in->selection_policy) {\n         case CXL_EXTENT_SELECTION_POLICY_PRESCRIPTIVE: {\n             /* Adding extents exceeds device's extent tracking ability. */\n@@ -4361,10 +4357,6 @@ static CXLRetCode cmd_fm_initiate_dc_release(const struct cxl_cmd *cmd,\n     CXLType3Dev *ct3d = CXL_TYPE3(cci->d);\n     int i, rc;\n \n-    if (ct3d->dc.total_capacity_cmd) {\n-        return CXL_MBOX_UNSUPPORTED;\n-    }\n-\n     switch (in->flags & CXL_EXTENT_REMOVAL_POLICY_MASK) {\n         case CXL_EXTENT_REMOVAL_POLICY_PRESCRIPTIVE: {\n             CXLDCExtentList updated_list;\ndiff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c\nindex 45fb6c55bc..569184975f 100644\n--- a/hw/mem/cxl_type3.c\n+++ b/hw/mem/cxl_type3.c\n@@ -30,6 +30,7 @@\n #include \"system/numa.h\"\n #include \"hw/cxl/cxl.h\"\n #include \"hw/pci/msix.h\"\n+#include \"qemu/uuid.h\"\n \n /* type3 device private */\n enum CXL_T3_MSIX_VECTOR {\n@@ -2289,13 +2290,42 @@ bool cxl_extent_groups_overlaps_dpa_range(CXLDCExtentGroupList *list,\n     return false;\n }\n \n+static bool cxl_device_lazy_dynamic_capacity_init(CXLType3Dev *ct3d,\n+                                                  const char *tag,\n+                                                  Error **errp)\n+{\n+    MemoryRegion *dc_mr;\n+\n+    ct3d->dc.host_dc = host_memory_backend_find_by_tag(tag);\n+    if (!ct3d->dc.host_dc) {\n+        error_setg(errp, \"dynamic capacity must have a backing device\");\n+        return false;\n+    }\n+\n+    dc_mr = host_memory_backend_get_memory(ct3d->dc.host_dc);\n+    if (!dc_mr) {\n+        error_setg(errp, \"dynamic capacity must have a backing device\");\n+        return false;\n+    }\n+\n+    if (host_memory_backend_is_mapped(ct3d->dc.host_dc)) {\n+        error_setg(errp,\n+                   \"memory backend %s is already mapped and cannot be reused\",\n+                   object_get_canonical_path_component(\n+                       OBJECT(ct3d->dc.host_dc)));\n+        return false;\n+    }\n+\n+    return true;\n+}\n+\n /*\n  * The main function to process dynamic capacity event with extent list.\n  * Currently DC extents add/release requests are processed.\n  */\n static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n         uint16_t hid, CXLDCEventType type, uint8_t rid,\n-        CxlDynamicCapacityExtentList *records, Error **errp)\n+        const char *tag, CxlDynamicCapacityExtentList *records, Error **errp)\n {\n     Object *obj;\n     CXLType3Dev *dcd;\n@@ -2303,7 +2333,8 @@ static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n     CxlDynamicCapacityExtentList *list;\n     CXLDCExtentGroup *group = NULL;\n     g_autofree CXLDCExtentRaw *extents = NULL;\n-    uint64_t dpa, offset, len, block_size;\n+    uint64_t dpa, offset, block_size;\n+    uint64_t len = 0;\n     g_autofree unsigned long *blk_bitmap = NULL;\n     int i;\n \n@@ -2319,13 +2350,6 @@ static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n         return;\n     }\n \n-    if (dcd->dc.total_capacity_cmd) {\n-        error_setg(errp,\n-                   \"dc-regions-total-size is set: extent add/release via QMP \"\n-                   \"not yet supported without a backing device at init\");\n-        return;\n-    }\n-\n     if (rid >= dcd->dc.num_regions) {\n         error_setg(errp, \"region id is too large\");\n         return;\n@@ -2334,6 +2358,8 @@ static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n     blk_bitmap = bitmap_new(dcd->dc.regions[rid].len / block_size);\n \n     /* Sanity check and count the extents */\n+    QemuUUID uuid;\n+    qemu_uuid_parse(tag, &uuid);\n     list = records;\n     while (list) {\n         offset = list->value->offset;\n@@ -2392,6 +2418,31 @@ static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n         num_extents++;\n     }\n \n+    if (type == DC_EVENT_ADD_CAPACITY && dcd->dc.total_capacity_cmd) {\n+        MemoryRegion *host_dc_mr;\n+        uint64_t size;\n+\n+        if (num_extents > 1) {\n+            error_setg(errp, \"Only single extent add is supported currently\");\n+            return;\n+        }\n+\n+        if (!cxl_device_lazy_dynamic_capacity_init(dcd, tag, errp)) {\n+            return;\n+        }\n+\n+        host_dc_mr = host_memory_backend_get_memory(dcd->dc.host_dc);\n+        size = memory_region_size(host_dc_mr);\n+\n+        if (size != len) {\n+            error_setg(errp,\n+                       \"Host memory backend size 0x%\" PRIx64\n+                       \" does not match extent length 0x%\" PRIx64,\n+                       size, len);\n+            return;\n+        }\n+    }\n+\n     /* Create extent list for event being passed to host */\n     i = 0;\n     list = records;\n@@ -2403,7 +2454,7 @@ static void qmp_cxl_process_dynamic_capacity_prescriptive(const char *path,\n \n         extents[i].start_dpa = dpa;\n         extents[i].len = len;\n-        memset(extents[i].tag, 0, 0x10);\n+        memcpy(extents[i].tag, &uuid.data, 0x10);\n         extents[i].shared_seq = 0;\n         if (type == DC_EVENT_ADD_CAPACITY) {\n             group = cxl_insert_extent_to_extent_group(group,\n@@ -2434,7 +2485,8 @@ void qmp_cxl_add_dynamic_capacity(const char *path, uint16_t host_id,\n     case CXL_EXTENT_SELECTION_POLICY_PRESCRIPTIVE:\n         qmp_cxl_process_dynamic_capacity_prescriptive(path, host_id,\n                                                       DC_EVENT_ADD_CAPACITY,\n-                                                      region, extents, errp);\n+                                                      region, tag,\n+                                                      extents, errp);\n         return;\n     default:\n         error_setg(errp, \"Selection policy not supported\");\n@@ -2465,7 +2517,8 @@ void qmp_cxl_release_dynamic_capacity(const char *path, uint16_t host_id,\n     switch (removal_policy) {\n     case CXL_EXTENT_REMOVAL_POLICY_PRESCRIPTIVE:\n         qmp_cxl_process_dynamic_capacity_prescriptive(path, host_id, type,\n-                                                      region, extents, errp);\n+                                                      region, tag,\n+                                                      extents, errp);\n         return;\n     default:\n         error_setg(errp, \"Removal policy not supported\");\n",
    "prefixes": [
        "3/9"
    ]
}