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GET /api/1.2/patches/2224339/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 2224339,
    "url": "http://patchwork.ozlabs.org/api/1.2/patches/2224339/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-3-119e66be10c2@avm.de/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/1.2/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": "<20260417-sdcard-performance-b4-v4-3-119e66be10c2@avm.de>",
    "list_archive_url": null,
    "date": "2026-04-17T09:51:36",
    "name": "[v4,3/7] hw/sd/sd: Use multi-byte/block writes for block path",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "4ee6fe3b8a6e330aaa7bee6e4acb512b3cf33b6e",
    "submitter": {
        "id": 91343,
        "url": "http://patchwork.ozlabs.org/api/1.2/people/91343/?format=api",
        "name": "Christian Speich",
        "email": "c.speich@avm.de"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-3-119e66be10c2@avm.de/mbox/",
    "series": [
        {
            "id": 500297,
            "url": "http://patchwork.ozlabs.org/api/1.2/series/500297/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500297",
            "date": "2026-04-17T09:51:34",
            "name": "hw/sd: Improve performance of read/write/erase",
            "version": 4,
            "mbox": "http://patchwork.ozlabs.org/series/500297/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2224339/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2224339/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
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        ],
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=avm.de; s=mail;\n t=1776419845; bh=QoyvxQROiGbE6vAvJxaG+85jruxRTacuSs9YktkmEG0=;\n h=From:Date:Subject:References:In-Reply-To:To:Cc:From;\n b=OPKm0GxdEpwO+n7aXHamI33uktNSIId8uheR7V3/x/MCVl1IjvdFq85n1S1ChZs/c\n gBk5D1rjOAVORQGUdDDXoXEfUwPZvU066FU9OYQ91F2ZWPaCwGI42O13y7GfQ6mIo0\n V2TwgMroMnWGDsXUXuy5qsEZOIL3LL0uZ7tcUino=",
        "From": "Christian Speich <c.speich@avm.de>",
        "Date": "Fri, 17 Apr 2026 11:51:36 +0200",
        "Subject": "[PATCH v4 3/7] hw/sd/sd: Use multi-byte/block writes for block\n path",
        "MIME-Version": "1.0",
        "Message-Id": "<20260417-sdcard-performance-b4-v4-3-119e66be10c2@avm.de>",
        "References": "<20260417-sdcard-performance-b4-v4-0-119e66be10c2@avm.de>",
        "In-Reply-To": "<20260417-sdcard-performance-b4-v4-0-119e66be10c2@avm.de>",
        "To": "qemu-devel@nongnu.org",
        "Cc": "=?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= <philmd@linaro.org>,\n Bin Meng <bmeng.cn@gmail.com>, qemu-block@nongnu.org,\n Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,\n Yanan Wang <wangyanan55@huawei.com>, Zhao Liu <zhao1.liu@intel.com>,\n Christian Speich <c.speich@avm.de>",
        "X-Mailer": "b4 0.14.2",
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        "X-TNEFEvaluated": "1",
        "Content-Transfer-Encoding": "7bit",
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        ],
        "Received-SPF": "pass client-ip=212.42.244.119; envelope-from=c.speich@avm.de;\n helo=mail.avm.de",
        "X-Spam_score_int": "-48",
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        "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>",
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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 writing/reading blocks via WRITE/READ_MULTIPLE_BLOCK we try to\ndirectly pass this request down to the block layer. This can only be done\nfor properly sized and aligned accesses, other access still use a bounce\nbuffer but still benefit from copying as much data in one memcpy as\npossible.\n\nRPMB is limited to the slow path using a bounce buffer.\n\nSigned-off-by: Christian Speich <c.speich@avm.de>\n---\n hw/sd/sd.c | 228 ++++++++++++++++++++++++++++++++++++++++++++++---------------\n 1 file changed, 172 insertions(+), 56 deletions(-)",
    "diff": "diff --git a/hw/sd/sd.c b/hw/sd/sd.c\nindex 2c81776df316feda75f97e15cc9bbd1538f1a21c..b27fed2e563e5971dd32787498eb8abed9ffe9be 100644\n--- a/hw/sd/sd.c\n+++ b/hw/sd/sd.c\n@@ -1112,24 +1112,36 @@ static const VMStateDescription sd_vmstate = {\n     },\n };\n \n-static void sd_blk_read(SDState *sd, uint64_t addr, uint32_t len)\n+static void sd_blk_read(SDState *sd, void* buf, uint64_t addr,\n+                        uint32_t len)\n {\n     trace_sdcard_read_block(addr, len);\n     addr += sd_part_offset(sd);\n-    if (!sd->blk || blk_pread(sd->blk, addr, len, sd->data, 0) < 0) {\n+    if (!sd->blk || blk_pread(sd->blk, addr, len, buf, 0) < 0) {\n         fprintf(stderr, \"sd_blk_read: read error on host side\\n\");\n     }\n }\n \n-static void sd_blk_write(SDState *sd, uint64_t addr, uint32_t len)\n+static void sd_blk_read_bounce_buffer(SDState *sd, uint64_t addr, uint32_t len)\n+{\n+    sd_blk_read(sd, sd->data, addr, len);\n+}\n+\n+static void sd_blk_write(SDState *sd, const void *buf, uint64_t addr,\n+                         uint32_t len)\n {\n     trace_sdcard_write_block(addr, len);\n     addr += sd_part_offset(sd);\n-    if (!sd->blk || blk_pwrite(sd->blk, addr, len, sd->data, 0) < 0) {\n+    if (!sd->blk || blk_pwrite(sd->blk, addr, len, buf, 0) < 0) {\n         fprintf(stderr, \"sd_blk_write: write error on host side\\n\");\n     }\n }\n \n+static void sd_blk_write_bounce_buffer(SDState *sd, uint64_t addr, uint32_t len)\n+{\n+    sd_blk_write(sd, sd->data, addr, len);\n+}\n+\n static bool rpmb_calc_hmac(SDState *sd, const RPMBDataFrame *frame,\n                            unsigned int num_blocks, uint8_t *mac)\n {\n@@ -1363,7 +1375,7 @@ static void sd_erase(SDState *sd)\n                 continue;\n             }\n         }\n-        sd_blk_write(sd, erase_addr, erase_len);\n+        sd_blk_write_bounce_buffer(sd, erase_addr, erase_len);\n     }\n }\n \n@@ -1984,7 +1996,7 @@ static sd_rsp_type_t sd_cmd_READ_SINGLE_BLOCK(SDState *sd, SDRequest req)\n         return sd_r1;\n     }\n \n-    sd_blk_read(sd, addr, sd->blk_len);\n+    sd_blk_read_bounce_buffer(sd, addr, sd->blk_len);\n     return sd_cmd_to_sendingdata(sd, req, addr, NULL, sd->blk_len);\n }\n \n@@ -2673,7 +2685,7 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n         if (sd_generic_write_data(sd, buf, &length)) {\n             /* TODO: Check CRC before committing */\n             sd->state = sd_programming_state;\n-            sd_blk_write(sd, sd->data_start, sd->data_offset);\n+            sd_blk_write_bounce_buffer(sd, sd->data_start, sd->data_offset);\n             sd->blk_written ++;\n             sd->csd[14] |= 0x40;\n             /* Bzzzzzzztt .... Operation complete.  */\n@@ -2682,44 +2694,85 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n         break;\n \n     case 25:  /* CMD25:  WRITE_MULTIPLE_BLOCK */\n-        /*\n-         * Only read one byte at a time. We will be called again with the\n-         * remaining.\n-         */\n-        length = 1;\n-\n-        if (sd->data_offset == 0) {\n-            /* Start of the block - let's check the address is valid */\n-            if (!address_in_range(sd, \"WRITE_MULTIPLE_BLOCK\",\n-                                  sd->data_start, sd->blk_len)) {\n-                break;\n+        if (!address_in_range(sd, \"WRITE_MULTIPLE_BLOCK\",\n+                            sd->data_start + sd->data_offset, length)) {\n+            /* Limit writing data to our device size */\n+            length = sd->size - sd->data_start - sd->data_offset;\n+\n+            /* We've read past the end, return a dummy write. */\n+            if (length == 0) {\n+                return 1;\n             }\n-            if (sd->size <= SDSC_MAX_CAPACITY) {\n-                if (sd_wp_addr(sd, sd->data_start)) {\n+        }\n+\n+        if (sd->size <= SDSC_MAX_CAPACITY) {\n+            uint64_t start = sd->data_start + sd->data_offset;\n+\n+            /*\n+             * Check if any covered address violates WP. If so, limit our write\n+             * up to the allowed address.\n+             */\n+            for (uint64_t addr = start; addr < start + length;\n+                 addr = ROUND_UP(addr + 1, WPGROUP_SIZE)) {\n+                if (sd_wp_addr(sd, addr)) {\n                     sd->card_status |= WP_VIOLATION;\n+\n+                    length = addr - start - 1;\n                     break;\n                 }\n             }\n         }\n-        sd->data[sd->data_offset++] = value[0];\n-        if (sd->data_offset >= sd->blk_len) {\n-            /* TODO: Check CRC before committing */\n-            sd->state = sd_programming_state;\n-            partition_access = sd->ext_csd[EXT_CSD_PART_CONFIG]\n-                    & EXT_CSD_PART_CONFIG_ACC_MASK;\n-            if (partition_access == EXT_CSD_PART_CONFIG_ACC_RPMB) {\n-                emmc_rpmb_blk_write(sd, sd->data_start, sd->data_offset);\n-            } else {\n-                sd_blk_write(sd, sd->data_start, sd->data_offset);\n+\n+        partition_access = sd->ext_csd[EXT_CSD_PART_CONFIG]\n+                            & EXT_CSD_PART_CONFIG_ACC_MASK;\n+\n+        /* Partial write or RPMB (single block only for now) */\n+        if (sd->data_offset > 0\n+            || partition_access == EXT_CSD_PART_CONFIG_ACC_RPMB) {\n+            length = MIN(sd->blk_len - sd->data_offset, length);\n+\n+            memcpy(sd->data + sd->data_offset, buf, length);\n+            sd->data_offset += length;\n+\n+            if (sd->data_offset >= sd->blk_len) {\n+                sd->state = sd_programming_state;\n+                if (partition_access == EXT_CSD_PART_CONFIG_ACC_RPMB) {\n+                    emmc_rpmb_blk_write(sd, sd->data_start, sd->data_offset);\n+                } else {\n+                    sd_blk_write_bounce_buffer(sd, sd->data_start,\n+                                               sd->data_offset);\n+                }\n+                sd->blk_written++;\n+                sd->data_start += sd->blk_len;\n+                sd->data_offset = 0;\n+                sd->csd[14] |= 0x40;\n+\n+                /* Bzzzzzzztt .... Operation complete.  */\n+                if (sd->multi_blk_cnt != 0) {\n+                    if (--sd->multi_blk_cnt == 0) {\n+                        /* Stop! */\n+                        sd->state = sd_transfer_state;\n+                        break;\n+                    }\n+                }\n+\n+                sd->state = sd_receivingdata_state;\n             }\n-            sd->blk_written++;\n-            sd->data_start += sd->blk_len;\n-            sd->data_offset = 0;\n+        }\n+        /* Try to write multiple of block sizes */\n+        else if (length >= sd->blk_len) {\n+            length = QEMU_ALIGN_DOWN(length, sd->blk_len);\n+\n+            sd->state = sd_programming_state;\n+            sd_blk_write(sd, buf, sd->data_start, length);\n+            sd->blk_written += length / sd->blk_len;\n+            sd->data_start += length;\n             sd->csd[14] |= 0x40;\n \n-            /* Bzzzzzzztt .... Operation complete.  */\n             if (sd->multi_blk_cnt != 0) {\n-                if (--sd->multi_blk_cnt == 0) {\n+                sd->multi_blk_cnt -= length / sd->blk_len;\n+\n+                if (sd->multi_blk_cnt == 0) {\n                     /* Stop! */\n                     sd->state = sd_transfer_state;\n                     break;\n@@ -2728,6 +2781,12 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n \n             sd->state = sd_receivingdata_state;\n         }\n+        /* Partial write */\n+        else if (length > 0) {\n+            memcpy(sd->data, buf, length);\n+            sd->data_offset = length;\n+        }\n+\n         break;\n \n     case 26:  /* CMD26:  PROGRAM_CID */\n@@ -2798,7 +2857,6 @@ static size_t sd_read_data(SDState *sd, void *buf, size_t length)\n     const uint8_t dummy_byte = 0x00;\n     unsigned int partition_access;\n     uint32_t io_len;\n-    uint8_t *value = buf;\n \n     if (!sd->blk || !blk_is_inserted(sd->blk)) {\n         memset(buf, dummy_byte, length);\n@@ -2838,36 +2896,94 @@ static size_t sd_read_data(SDState *sd, void *buf, size_t length)\n         break;\n \n     case 18:  /* CMD18:  READ_MULTIPLE_BLOCK */\n+        if (!address_in_range(sd, \"READ_MULTIPLE_BLOCK\",\n+                              sd->data_start + sd->data_offset, length)) {\n+            /* Limit reading data to our device size */\n+            length = sd->size - sd->data_start - sd->data_offset;\n+\n+            /* We read past the end, return a dummy read. */\n+            if (length == 0) {\n+                memset(buf, dummy_byte, 1);\n+                return 1;\n+            }\n+        }\n+\n+        partition_access = sd->ext_csd[EXT_CSD_PART_CONFIG]\n+                & EXT_CSD_PART_CONFIG_ACC_MASK;\n+\n+        /* We have a partially read block. */\n+        if (sd->data_offset > 0) {\n+            length = MIN(sd->data_size - sd->data_offset, length);\n+\n+            memcpy(buf, sd->data + sd->data_offset, length);\n+\n+            sd->data_offset += length;\n+\n+            /* Partial read is complete, clear state. */\n+            if (sd->data_offset >= sd->data_size) {\n+                sd->data_start += io_len;\n+                sd->data_size = 0;\n+                sd->data_offset = 0;\n+\n+                if (sd->multi_blk_cnt != 0) {\n+                    if (--sd->multi_blk_cnt == 0) {\n+                        sd->state = sd_transfer_state;\n+                    }\n+                }\n+            }\n+        }\n         /*\n-         * We will only read one byte at a time. We will be called again with\n-         * the remaining buffer.\n+         * Try to read multiples of the block size directly bypassing the local\n+         * bounce buffer.\n+         * Not for RPMB.\n          */\n-        length = 1;\n+        else if (length >= io_len\n+                 && partition_access != EXT_CSD_PART_CONFIG_ACC_RPMB) {\n+            length = QEMU_ALIGN_DOWN(length, io_len);\n \n-        if (sd->data_offset == 0) {\n-            if (!address_in_range(sd, \"READ_MULTIPLE_BLOCK\",\n-                                  sd->data_start, io_len)) {\n-                return dummy_byte;\n+            /* For limited reads, only read the requested block count. */\n+            if (sd->multi_blk_cnt != 0) {\n+                length = MIN(length, sd->multi_blk_cnt * io_len);\n             }\n-            partition_access = sd->ext_csd[EXT_CSD_PART_CONFIG]\n-                    & EXT_CSD_PART_CONFIG_ACC_MASK;\n+\n+            sd_blk_read(sd, buf, sd->data_start, length);\n+\n+            sd->data_start += length;\n+\n+            if (sd->multi_blk_cnt != 0) {\n+                sd->multi_blk_cnt -= length / io_len;\n+\n+                if (sd->multi_blk_cnt == 0) {\n+                    sd->state = sd_transfer_state;\n+                }\n+            }\n+        }\n+        /* Read partial at the end or sinlge-block RPMB */\n+        else if (length > 0) {\n+            length = MIN(length, io_len);\n+\n+            /* Fill the buffer */\n             if (partition_access == EXT_CSD_PART_CONFIG_ACC_RPMB) {\n                 emmc_rpmb_blk_read(sd, sd->data_start, io_len);\n             } else {\n-                sd_blk_read(sd, sd->data_start, io_len);\n+                sd_blk_read_bounce_buffer(sd, sd->data_start, io_len);\n             }\n-        }\n-        *value = sd->data[sd->data_offset++];\n \n-        if (sd->data_offset >= io_len) {\n-            sd->data_start += io_len;\n-            sd->data_offset = 0;\n+            memcpy(buf, sd->data, length);\n \n-            if (sd->multi_blk_cnt != 0) {\n-                if (--sd->multi_blk_cnt == 0) {\n-                    /* Stop! */\n-                    sd->state = sd_transfer_state;\n-                    break;\n+            sd->data_size = io_len;\n+            sd->data_offset = length;\n+\n+            if (sd->data_offset >= io_len) {\n+                sd->data_start += io_len;\n+                sd->data_offset = 0;\n+\n+                if (sd->multi_blk_cnt != 0) {\n+                    if (--sd->multi_blk_cnt == 0) {\n+                        /* Stop! */\n+                        sd->state = sd_transfer_state;\n+                        break;\n+                    }\n                 }\n             }\n         }\n",
    "prefixes": [
        "v4",
        "3/7"
    ]
}