{"id":2224396,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2224396/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417105618.3621-35-magnuskulke@linux.microsoft.com/","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":"<20260417105618.3621-35-magnuskulke@linux.microsoft.com>","list_archive_url":null,"date":"2026-04-17T10:56:18","name":"[34/34] accel/mshv: enable dirty page tracking","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"bb5d4611edce431a0e8341d72cb499c789381c89","submitter":{"id":90753,"url":"http://patchwork.ozlabs.org/api/1.2/people/90753/?format=json","name":"Magnus Kulke","email":"magnuskulke@linux.microsoft.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417105618.3621-35-magnuskulke@linux.microsoft.com/mbox/","series":[{"id":500310,"url":"http://patchwork.ozlabs.org/api/1.2/series/500310/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500310","date":"2026-04-17T10:55:44","name":"Add migration support to the MSHV accelerator","version":1,"mbox":"http://patchwork.ozlabs.org/series/500310/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224396/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224396/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=linux.microsoft.com header.i=@linux.microsoft.com\n header.a=rsa-sha256 header.s=default header.b=mxWuLjOE;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.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 4fxsLx3z1xz1yHp\n\tfor ; Fri, 17 Apr 2026 20:58:49 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wDguJ-0006y4-RG; Fri, 17 Apr 2026 06:58:43 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wDguI-0006qK-Sv\n for qemu-devel@nongnu.org; Fri, 17 Apr 2026 06:58:42 -0400","from linux.microsoft.com ([13.77.154.182])\n by eggs.gnu.org with esmtp (Exim 4.90_1)\n (envelope-from ) id 1wDguG-0001us-RB\n for qemu-devel@nongnu.org; Fri, 17 Apr 2026 06:58:42 -0400","from DESKTOP-TUU1E5L.fritz.box (p5086d620.dip0.t-ipconnect.de\n [80.134.214.32])\n by linux.microsoft.com (Postfix) with ESMTPSA id B45C020B6F08;\n Fri, 17 Apr 2026 03:58:26 -0700 (PDT)"],"DKIM-Filter":"OpenDKIM Filter v2.11.0 linux.microsoft.com B45C020B6F08","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com;\n s=default; t=1776423509;\n bh=kvyTJIDUKe7YqJFl71haRQV2T+y2d3dK1b5PZUwcZ2w=;\n h=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n b=mxWuLjOEjAUxvNIuLYImGpTmtpHsNR/BxLzlKu8IQOA72Xf3/D71fBE+NIq3Xv6v0\n 6mZ/NoXIThzSW8ZkS4JS0q4wtISOnoAOhS2Iv28M69oFJGEBaYpyM9p1AQJGJJGbx5\n ce81SVv33BhYpGdjLCSXj08L3KI78573fswxroM4=","From":"Magnus Kulke ","To":"qemu-devel@nongnu.org","Cc":"kvm@vger.kernel.org, Magnus Kulke ,\n Wei Liu , \"Michael S. Tsirkin\" ,\n\t=?utf-8?q?C=C3=A9dric_Le_Goater?= ,\n Zhao Liu ,\n Richard Henderson ,\n Paolo Bonzini , Wei Liu ,\n Magnus Kulke ,\n Alex Williamson ,\n Marcel Apfelbaum , =?utf-8?q?Philippe_Mathieu-D?=\n\t=?utf-8?q?aud=C3=A9?= ,\n Marcelo Tosatti ","Subject":"[PATCH 34/34] accel/mshv: enable dirty page tracking","Date":"Fri, 17 Apr 2026 12:56:18 +0200","Message-Id":"<20260417105618.3621-35-magnuskulke@linux.microsoft.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20260417105618.3621-1-magnuskulke@linux.microsoft.com>","References":"<20260417105618.3621-1-magnuskulke@linux.microsoft.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=13.77.154.182;\n envelope-from=magnuskulke@linux.microsoft.com; helo=linux.microsoft.com","X-Spam_score_int":"-42","X-Spam_score":"-4.3","X-Spam_bar":"----","X-Spam_report":"(-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-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":"This change introduces the functions required to perform dirty page\ntracking to speed up migrations. We are using the sync, global_start,\nand global_stop hooks.\n\nThe sync is implemented in batches.\n\nBefore we can disable the dirty page tracking we have to set all dirty bits.\n\nSigned-off-by: Magnus Kulke \n---\n accel/mshv/mem.c | 211 ++++++++++++++++++++++++++++++++++++++\n accel/mshv/mshv-all.c | 3 +\n include/system/mshv_int.h | 5 +\n 3 files changed, 219 insertions(+)","diff":"diff --git a/accel/mshv/mem.c b/accel/mshv/mem.c\nindex e55c38d4db..820f87ef0c 100644\n--- a/accel/mshv/mem.c\n+++ b/accel/mshv/mem.c\n@@ -12,10 +12,13 @@\n \n #include \"qemu/osdep.h\"\n #include \"qemu/error-report.h\"\n+#include \"qapi/error.h\"\n #include \"linux/mshv.h\"\n #include \"system/address-spaces.h\"\n #include \"system/mshv.h\"\n #include \"system/mshv_int.h\"\n+#include \"hw/hyperv/hvhdk_mini.h\"\n+#include \"system/physmem.h\"\n #include \"exec/memattrs.h\"\n #include \n #include \"trace.h\"\n@@ -211,3 +214,211 @@ void mshv_set_phys_mem(MshvMemoryListener *mml, MemoryRegionSection *section,\n abort();\n }\n }\n+\n+static int enable_dirty_page_tracking(int vm_fd)\n+{\n+ int ret;\n+ struct hv_input_set_partition_property in = {0};\n+ struct mshv_root_hvcall args = {0};\n+\n+ in.property_code = HV_PARTITION_PROPERTY_GPA_PAGE_ACCESS_TRACKING;\n+ in.property_value = 1;\n+\n+ args.code = HVCALL_SET_PARTITION_PROPERTY;\n+ args.in_sz = sizeof(in);\n+ args.in_ptr = (uint64_t)∈\n+\n+ ret = mshv_hvcall(vm_fd, &args);\n+ if (ret < 0) {\n+ error_report(\"Failed to enable dirty page tracking: %s\",\n+ strerror(errno));\n+ return -1;\n+ }\n+\n+ return 0;\n+}\n+\n+/*\n+ * Retrieve dirty page bitmap for a GPA range, clearing the dirty bits\n+ * atomically. Large ranges are handled in batches.\n+ */\n+static int get_dirty_log(int vm_fd, uint64_t base_pfn, uint64_t page_count,\n+ unsigned long *bitmap, size_t bitmap_size)\n+{\n+ uint64_t batch, bitmap_offset, completed = 0;\n+ struct mshv_gpap_access_bitmap args = {0};\n+ int ret;\n+\n+ QEMU_BUILD_BUG_ON(MSHV_DIRTY_PAGES_BATCH_SIZE % BITS_PER_LONG != 0);\n+ assert(bitmap_size >= ROUND_UP(page_count, BITS_PER_LONG) / 8);\n+\n+ while (completed < page_count) {\n+ batch = MIN(MSHV_DIRTY_PAGES_BATCH_SIZE, page_count - completed);\n+ bitmap_offset = completed / BITS_PER_LONG;\n+\n+ args.access_type = MSHV_GPAP_ACCESS_TYPE_DIRTY;\n+ args.access_op = MSHV_GPAP_ACCESS_OP_CLEAR;\n+ args.page_count = batch;\n+ args.gpap_base = base_pfn + completed;\n+ args.bitmap_ptr = (uint64_t)(bitmap + bitmap_offset);\n+\n+ ret = ioctl(vm_fd, MSHV_GET_GPAP_ACCESS_BITMAP, &args);\n+ if (ret < 0) {\n+ error_report(\"Failed to get dirty log (base_pfn=0x%\" PRIx64\n+ \" batch=%\" PRIu64 \"): %s\",\n+ base_pfn + completed, batch, strerror(errno));\n+ return -1;\n+ }\n+ completed += batch;\n+ }\n+\n+ return 0;\n+}\n+\n+bool mshv_log_global_start(MemoryListener *listener, Error **errp)\n+{\n+ int ret;\n+\n+ ret = enable_dirty_page_tracking(mshv_state->vm);\n+ if (ret < 0) {\n+ error_setg_errno(errp, -ret, \"Failed to enable dirty page tracking\");\n+ return false;\n+ }\n+ return true;\n+}\n+\n+static int disable_dirty_page_tracking(int vm_fd)\n+{\n+ int ret;\n+ struct hv_input_set_partition_property in = {0};\n+ struct mshv_root_hvcall args = {0};\n+\n+ in.property_code = HV_PARTITION_PROPERTY_GPA_PAGE_ACCESS_TRACKING;\n+ in.property_value = 0;\n+\n+ args.code = HVCALL_SET_PARTITION_PROPERTY;\n+ args.in_sz = sizeof(in);\n+ args.in_ptr = (uint64_t)∈\n+\n+ ret = mshv_hvcall(vm_fd, &args);\n+ if (ret < 0) {\n+ error_report(\"Failed to disable dirty page tracking: %s\",\n+ strerror(errno));\n+ return -1;\n+ }\n+\n+ return 0;\n+}\n+\n+static int set_dirty_pages(int vm_fd, uint64_t base_pfn, uint64_t page_count)\n+{\n+ uint64_t batch, completed = 0;\n+ unsigned long bitmap[MSHV_DIRTY_PAGES_BATCH_SIZE / BITS_PER_LONG];\n+ struct mshv_gpap_access_bitmap args = {0};\n+ int ret;\n+\n+ while (completed < page_count) {\n+ batch = MIN(MSHV_DIRTY_PAGES_BATCH_SIZE, page_count - completed);\n+\n+ args.access_type = MSHV_GPAP_ACCESS_TYPE_DIRTY;\n+ args.access_op = MSHV_GPAP_ACCESS_OP_SET;\n+ args.page_count = batch;\n+ args.gpap_base = base_pfn + completed;\n+ args.bitmap_ptr = (uint64_t)bitmap;\n+\n+ ret = ioctl(vm_fd, MSHV_GET_GPAP_ACCESS_BITMAP, &args);\n+ if (ret < 0) {\n+ error_report(\"Failed to set dirty pages (base_pfn=0x%\" PRIx64\n+ \" batch=%\" PRIu64 \"): %s\",\n+ base_pfn + completed, batch, strerror(errno));\n+ return -1;\n+ }\n+ completed += batch;\n+ }\n+\n+ return 0;\n+}\n+\n+static bool set_dirty_bits_cb(Int128 start, Int128 len, const MemoryRegion *mr,\n+ hwaddr offset_in_region, void *opaque)\n+{\n+ int ret, *errp = opaque;\n+ hwaddr gpa, size;\n+ uint64_t page_count, base_pfn;\n+\n+ gpa = int128_get64(start);\n+ size = int128_get64(len);\n+ page_count = size >> MSHV_PAGE_SHIFT;\n+ base_pfn = gpa >> MSHV_PAGE_SHIFT;\n+\n+ if (!mr->ram || mr->readonly) {\n+ return false;\n+ }\n+\n+ if (page_count == 0) {\n+ return false;\n+ }\n+\n+ ret = set_dirty_pages(mshv_state->vm, base_pfn, page_count);\n+\n+ /* true aborts the iteration, which is what we want if there's an error */\n+ if (ret < 0) {\n+ *errp = ret;\n+ return true;\n+ }\n+\n+ return false;\n+}\n+\n+void mshv_log_global_stop(MemoryListener *listener)\n+{\n+ int err = 0;\n+ /* MSHV requires all dirty bits to be set before disabling tracking. */\n+ FlatView *fv = address_space_to_flatview(&address_space_memory);\n+ flatview_for_each_range(fv, set_dirty_bits_cb, &err);\n+\n+ if (err < 0) {\n+ error_report(\"Failed to set dirty bits before disabling tracking\");\n+ }\n+\n+ disable_dirty_page_tracking(mshv_state->vm);\n+}\n+\n+void mshv_log_sync(MemoryListener *listener, MemoryRegionSection *section)\n+{\n+ hwaddr size, start_addr, mr_offset;\n+ uint64_t page_count, base_pfn;\n+ size_t bitmap_size;\n+ unsigned long *bitmap;\n+ ram_addr_t ram_addr;\n+ int ret;\n+ MemoryRegion *mr = section->mr;\n+\n+ if (!memory_region_is_ram(mr) || memory_region_is_rom(mr)) {\n+ return;\n+ }\n+\n+ size = align_section(section, &start_addr);\n+ if (!size) {\n+ return;\n+ }\n+\n+ page_count = size >> MSHV_PAGE_SHIFT;\n+ base_pfn = start_addr >> MSHV_PAGE_SHIFT;\n+ bitmap_size = ROUND_UP(page_count, BITS_PER_LONG) / 8;\n+ bitmap = g_malloc0(bitmap_size);\n+\n+ ret = get_dirty_log(mshv_state->vm, base_pfn, page_count, bitmap,\n+ bitmap_size);\n+ if (ret < 0) {\n+ g_free(bitmap);\n+ return;\n+ }\n+\n+ mr_offset = section->offset_within_region + start_addr -\n+ section->offset_within_address_space;\n+ ram_addr = memory_region_get_ram_addr(mr) + mr_offset;\n+\n+ physical_memory_set_dirty_lebitmap(bitmap, ram_addr, page_count);\n+ g_free(bitmap);\n+}\ndiff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c\nindex ffe84d6151..94ff9cdb49 100644\n--- a/accel/mshv/mshv-all.c\n+++ b/accel/mshv/mshv-all.c\n@@ -546,6 +546,9 @@ static MemoryListener mshv_memory_listener = {\n .region_del = mem_region_del,\n .eventfd_add = mem_ioeventfd_add,\n .eventfd_del = mem_ioeventfd_del,\n+ .log_sync = mshv_log_sync,\n+ .log_global_start = mshv_log_global_start,\n+ .log_global_stop = mshv_log_global_stop,\n };\n \n static MemoryListener mshv_io_listener = {\ndiff --git a/include/system/mshv_int.h b/include/system/mshv_int.h\nindex c24efc8675..ddbdd76076 100644\n--- a/include/system/mshv_int.h\n+++ b/include/system/mshv_int.h\n@@ -31,6 +31,8 @@ struct mshv_get_set_vp_state;\n #define MSHV_HV_INTERRUPTION_TYPE_PRIV_SW_EXC 5\n #define MSHV_HV_INTERRUPTION_TYPE_SW_EXC 6\n \n+#define MSHV_DIRTY_PAGES_BATCH_SIZE 0x10000\n+\n typedef struct hyperv_message hv_message;\n \n typedef struct MshvHvCallArgs {\n@@ -128,6 +130,9 @@ int mshv_guest_mem_write(uint64_t gpa, const uint8_t *data, uintptr_t size,\n bool is_secure_mode);\n void mshv_set_phys_mem(MshvMemoryListener *mml, MemoryRegionSection *section,\n bool add);\n+void mshv_log_sync(MemoryListener *listener, MemoryRegionSection *section);\n+bool mshv_log_global_start(MemoryListener *listener, Error **errp);\n+void mshv_log_global_stop(MemoryListener *listener);\n \n /* msr */\n int mshv_init_msrs(const CPUState *cpu);\n","prefixes":["34/34"]}