{"id":2224335,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2224335/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-6-119e66be10c2@avm.de/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.2/projects/14/?format=json","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-v4-6-119e66be10c2@avm.de>","list_archive_url":null,"date":"2026-04-17T09:51:39","name":"[v4,6/7] hw/sd/sdcard: Optimize erase blocks as zero.","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"2f3f319bc43b50a0230b9f6aa51d90043831497a","submitter":{"id":91343,"url":"http://patchwork.ozlabs.org/api/1.2/people/91343/?format=json","name":"Christian Speich","email":"c.speich@avm.de"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-6-119e66be10c2@avm.de/mbox/","series":[{"id":500297,"url":"http://patchwork.ozlabs.org/api/1.2/series/500297/?format=json","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/2224335/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224335/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=avm.de header.i=@avm.de header.a=rsa-sha256\n header.s=mail header.b=ZK9i54fo;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Fri, 17 Apr 2026 11:57:26 +0200","from mail-notes.avm.de (mail-notes.avm.de [172.16.0.1])\n by mail.avm.de (Postfix) with ESMTP;\n Fri, 17 Apr 2026 11:57:26 +0200 (CEST)","from [127.0.1.1] ([172.17.89.139])\n by mail-notes.avm.de (HCL Domino Release 14.0FP4)\n with ESMTP id 2026041711572445-2979 ;\n Fri, 17 Apr 2026 11:57:24 +0200"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=avm.de; s=mail;\n t=1776419846; bh=5SYH+A8NyAGbb6vSKm8RhEoSuVLKy93+R7omElZI8D4=;\n h=From:Date:Subject:References:In-Reply-To:To:Cc:From;\n b=ZK9i54fox3XJjwgzlj4oZZGMT+xviuIjKa+l5O2HvQKizvFaHch20mI7QrWVrhR7G\n XkISUDdCmBiW5aQYukofDLW5d5bDLo6CdBz0ziQDpBt5zdHrQrhKqSLoPkHIIqdZfQ\n ooHJafZY5mXIDPjh+dBlIRsOKJRQ6aNcYzQ+yBrk=","From":"Christian Speich ","Date":"Fri, 17 Apr 2026 11:51:39 +0200","Subject":"[PATCH v4 6/7] hw/sd/sdcard: Optimize erase blocks as zero.","MIME-Version":"1.0","Message-Id":"<20260417-sdcard-performance-b4-v4-6-119e66be10c2@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?= ,\n Bin Meng , qemu-block@nongnu.org,\n Marcel Apfelbaum ,\n Yanan Wang , Zhao Liu ,\n Christian Speich ","X-Mailer":"b4 0.14.2","X-MIMETrack":"Itemize by SMTP Server on ANIS1/AVM(Release 14.0FP4|March 10,\n 2025) at 17.04.2026 11:57:24,\n Serialize by Router on ANIS1/AVM(Release 14.0FP4|March 10, 2025) at\n 17.04.2026 11:57:26, Serialize complete at 17.04.2026 11:57:26","X-TNEFEvaluated":"1","Content-Transfer-Encoding":"7bit","Content-Type":"text/plain; charset=\"utf-8\"","X-purgate-ID":"149429::1776419846-50F26373-590759AA/0/0","X-purgate-type":"clean","X-purgate-size":"3267","X-purgate-Ad":"Categorized by eleven eXpurgate (R) https://www.eleven.de","X-purgate":["This mail is considered clean (visit https://www.eleven.de for\n further information)","clean"],"Received-SPF":"pass client-ip=2001:bf0:244:244::119;\n envelope-from=c.speich@avm.de; helo=mail.avm.de","X-Spam_score_int":"-25","X-Spam_score":"-2.6","X-Spam_bar":"--","X-Spam_report":"(-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\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 ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"When erasing blocks as zero, we can use optimized block functions to\nachieve this.\n\nThese allow us to request a large rage to be zeroed, possible optimizing\nthis operation and freeing disk space for sparsesly stored images.\n\nThis only is possible when erase-blocks-as-zero=true is used and can\nprovide a significant performance boost. The case where 0xFF is used\nduring erase is as slow as before.\n\nSigned-off-by: Christian Speich \n---\n hw/sd/sd.c | 43 +++++++++++++++++++++++++++++++++----------\n 1 file changed, 33 insertions(+), 10 deletions(-)","diff":"diff --git a/hw/sd/sd.c b/hw/sd/sd.c\nindex 0f997ed8cc80e38645101cb8f47c86f1c30d5a25..d1ff9badb39b699ce734a533ccebfab894958d2d 100644\n--- a/hw/sd/sd.c\n+++ b/hw/sd/sd.c\n@@ -1331,6 +1331,26 @@ exit:\n trace_sdcard_rpmb_write_block(req, lduw_be_p(&sd->rpmb.result.result));\n }\n \n+/* Requires sd->buf to be filled with 0xFF */\n+static void sd_erase_ff(SDState *sd, uint64_t addr, size_t len)\n+{\n+ int erase_len = 1 << HWBLOCK_SHIFT;\n+ uint64_t erase_addr;\n+\n+ for (erase_addr = addr; erase_addr < addr + len; erase_addr += erase_len) {\n+ sd_blk_write_bounce_buffer(sd, erase_addr, erase_len);\n+ }\n+}\n+\n+static void sd_blk_erase(SDState *sd, uint64_t addr, size_t len)\n+{\n+ if (sd->erase_blocks_as_zero) {\n+ blk_pwrite_zeroes(sd->blk, addr + sd_part_offset(sd), len, 0);\n+ } else {\n+ sd_erase_ff(sd, addr, len);\n+ }\n+}\n+\n static void sd_erase(SDState *sd)\n {\n uint64_t erase_start = sd->erase_start;\n@@ -1338,7 +1358,6 @@ static void sd_erase(SDState *sd)\n bool sdsc = true;\n uint64_t wpnum;\n uint64_t erase_addr;\n- int erase_len = 1 << HWBLOCK_SHIFT;\n \n trace_sdcard_erase(sd->erase_start, sd->erase_end);\n if (sd->erase_start == INVALID_ADDRESS\n@@ -1367,24 +1386,28 @@ static void sd_erase(SDState *sd)\n sd->erase_end = INVALID_ADDRESS;\n sd->csd[14] |= 0x40;\n \n- if (sd->erase_blocks_as_zero) {\n- memset(sd->data, 0x0, erase_len);\n- } else {\n- memset(sd->data, 0xFF, erase_len);\n+ if (!sd->erase_blocks_as_zero) {\n+ memset(sd->data, 0xFF, 1 << HWBLOCK_SHIFT);\n }\n \n- for (erase_addr = erase_start; erase_addr <= erase_end;\n- erase_addr += erase_len) {\n- if (sdsc) {\n- /* Only SDSC cards support write protect groups */\n+ /* Only SDSC cards support write protect groups */\n+ if (sdsc) {\n+ for (erase_addr = erase_start; erase_addr <= erase_end;\n+ erase_addr = ROUND_UP(erase_addr + 1, WPGROUP_SIZE)) {\n+ uint64_t wp_group_end = ROUND_UP(erase_addr + 1, WPGROUP_SIZE) - 1;\n+ size_t erase_len = MIN(erase_end, wp_group_end) - erase_addr;\n+\n wpnum = sd_addr_to_wpnum(erase_addr);\n assert(wpnum < sd->wp_group_bits);\n if (test_bit(wpnum, sd->wp_group_bmap)) {\n sd->card_status |= WP_ERASE_SKIP;\n continue;\n }\n+\n+ sd_blk_erase(sd, erase_addr, erase_len);\n }\n- sd_blk_write_bounce_buffer(sd, erase_addr, erase_len);\n+ } else {\n+ sd_blk_erase(sd, erase_start, erase_end - erase_start);\n }\n }\n \n","prefixes":["v4","6/7"]}