From nobody Sat May 4 11:10:25 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=virtuozzo.com ARC-Seal: i=1; a=rsa-sha256; t=1616090152; cv=none; d=zohomail.com; s=zohoarc; b=murUoQGyf8K+flaG893XwuS0uGCE4DkFPIkN+E0nU9ya+i6yFRpoiDpYVeJRvdL2IhlsLRvp+B2gXRoAXb+sr0DR5YoDk3mRFdkgBbHjJFiY/nf2m1WHYaalrBirsJfkGCOzBnvM7l0SbUeVTrQ3x0ftp9x5iPHlFwr7rw3I17c= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1616090152; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=MScp47mP2GSzPvDDLgNYaohl9N5xLJLqTqhsqKVdSeE=; b=a1pUzTUlVylPtv+THO82Upd18GIqgX79KKZVdyoicmIVDgLfKgGssKdD56NMcKplyZM3v/4AhGcNRBRcRe0Hy7BQBubByvFkn0jGWj8mSaq+g+6pSsQJCGtZF1FYbOPMwvKcT7agUuXJQ4KsYFUPctsToBzwoVo4Sbi6buFm+vg= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1616090152154274.60705007629485; Thu, 18 Mar 2021 10:55:52 -0700 (PDT) Received: from localhost ([::1]:57248 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMwsA-0003Cy-8Q for importer@patchew.org; Thu, 18 Mar 2021 13:55:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53306) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwkD-0005sz-SY for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:47:43 -0400 Received: from relay.sw.ru ([185.231.240.75]:57650) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwk4-0007mF-V3 for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:47:37 -0400 Received: from [192.168.15.248] (helo=andrey-MS-7B54.sw.ru) by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1lMwjO-003De5-9Q; Thu, 18 Mar 2021 20:46:46 +0300 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=MIME-Version:Message-Id:Date:Subject:From: Content-Type; bh=MScp47mP2GSzPvDDLgNYaohl9N5xLJLqTqhsqKVdSeE=; b=MXRCMl56Vw4K YJDKOmHzkMq5YOfvs/0mtW1hGRWLQwyLB5796lepOCyAnmrCpH9WoWFmwwKkpal1yJEOmwbFwO7Dh ktNrkIaBdrJlqGmW7an/FJ8/rDaAqpNzq9G4jSFhJHM6w3uGj9FogMBsJIjEHUMVtO008J7FCnK0L JBZQE=; From: Andrey Gruzdev To: qemu-devel@nongnu.org Cc: Den Lunev , Eric Blake , Paolo Bonzini , Juan Quintela , "Dr . David Alan Gilbert" , Markus Armbruster , Peter Xu , David Hildenbrand , Andrey Gruzdev Subject: [PATCH 1/3] migration: Fix missing qemu_fflush() on buffer file in bg_migration_thread Date: Thu, 18 Mar 2021 20:46:09 +0300 Message-Id: <20210318174611.293520-2-andrey.gruzdev@virtuozzo.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> References: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.gruzdev@virtuozzo.com; helo=relay.sw.ru X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @virtuozzo.com) Content-Type: text/plain; charset="utf-8" Added missing qemu_fflush() on buffer file holding precopy device state. Increased initial QIOChannelBuffer allocation to 512KB to avoid reallocs. Typical configurations often require >200KB for device state and VMDESC. Signed-off-by: Andrey Gruzdev --- migration/migration.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration/migration.c b/migration/migration.c index 36768391b6..496cf6e17b 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -3857,7 +3857,7 @@ static void *bg_migration_thread(void *opaque) * with vCPUs running and, finally, write stashed non-RAM part of * the vmstate from the buffer to the migration stream. */ - s->bioc =3D qio_channel_buffer_new(128 * 1024); + s->bioc =3D qio_channel_buffer_new(512 * 1024); qio_channel_set_name(QIO_CHANNEL(s->bioc), "vmstate-buffer"); fb =3D qemu_fopen_channel_output(QIO_CHANNEL(s->bioc)); object_unref(OBJECT(s->bioc)); @@ -3911,6 +3911,8 @@ static void *bg_migration_thread(void *opaque) if (qemu_savevm_state_complete_precopy_non_iterable(fb, false, false))= { goto fail; } + qemu_fflush(fb); + /* Now initialize UFFD context and start tracking RAM writes */ if (ram_write_tracking_start()) { goto fail; --=20 2.25.1 From nobody Sat May 4 11:10:25 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=virtuozzo.com ARC-Seal: i=1; a=rsa-sha256; t=1616090641; cv=none; d=zohomail.com; s=zohoarc; b=nmQRn9QWqJf8IKYJOoYm5acO06UnCLbAWXrZiyMjdML1do6l3HxApXXmllJFgCGg+QjYv9a+RuijIHCHf9585hjjZyf9J5EZFETAToFzWHeTwCQPzaOMaN5P03nIxTWDEVPi33w1sFOeFe5ZOgVuvtFuxSiGeIJ3q+9BE/Jc9R8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1616090641; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=twgg4Z8xG2CcH6Cma/P0ULRnshzs58g8AoicKzYomz4=; b=YKXxsLg9yChJ9dBaE8WURY5/J6pIT4OpVstHiHI5wZQEXJBvvDRmHwNynTB06zJJnDq/yXnfpg9w/tdQU4zroQNupsGdAZEuYFu2TA/uxVq+6jdt5FvXNdCgMCaORb808jtyxERryYLm+1InNPjPqW9I8N2T5fycElBW8MPPlgc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1616090641529898.6492881340581; Thu, 18 Mar 2021 11:04:01 -0700 (PDT) Received: from localhost ([::1]:43918 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMx03-0001nJ-Ka for importer@patchew.org; Thu, 18 Mar 2021 14:03:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwkk-0006JQ-Dx for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:48:12 -0400 Received: from relay.sw.ru ([185.231.240.75]:57932) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwkb-00084H-Fy for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:48:08 -0400 Received: from [192.168.15.248] (helo=andrey-MS-7B54.sw.ru) by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1lMwjy-003De5-3N; Thu, 18 Mar 2021 20:47:22 +0300 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=MIME-Version:Message-Id:Date:Subject:From: Content-Type; bh=twgg4Z8xG2CcH6Cma/P0ULRnshzs58g8AoicKzYomz4=; b=eOgnKionxB90 YA8SItefiq2o3KqOSBO3MHg5Xxl77oEGZCcGmp9UcP/RtARm21TDiKxq+um9Rji0xEEvmHtvgwxQ9 OobzjXRd8za1ZXtF6yzQAn6kz9DyHndmMvXEsJp52iPlQ66hnsNazyZULalq+tPHvpoJqgkCSjvr5 zXa+8=; From: Andrey Gruzdev To: qemu-devel@nongnu.org Cc: Den Lunev , Eric Blake , Paolo Bonzini , Juan Quintela , "Dr . David Alan Gilbert" , Markus Armbruster , Peter Xu , David Hildenbrand , Andrey Gruzdev Subject: [PATCH 2/3] migration: Inhibit virtio-balloon for the duration of background snapshot Date: Thu, 18 Mar 2021 20:46:10 +0300 Message-Id: <20210318174611.293520-3-andrey.gruzdev@virtuozzo.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> References: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.gruzdev@virtuozzo.com; helo=relay.sw.ru X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @virtuozzo.com) Content-Type: text/plain; charset="utf-8" The same thing as for incoming postcopy - we cannot deal with concurrent RAM discards when using background snapshot feature in outgoing migration. Signed-off-by: Andrey Gruzdev Reviewed-by: David Hildenbrand --- hw/virtio/virtio-balloon.c | 8 ++++++-- include/migration/misc.h | 2 ++ migration/migration.c | 8 ++++++++ 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index e770955176..d120bf8f43 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -66,8 +66,12 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloone= dPage *pbp, =20 static bool virtio_balloon_inhibited(void) { - /* Postcopy cannot deal with concurrent discards, so it's special. */ - return ram_block_discard_is_disabled() || migration_in_incoming_postco= py(); + /* + * Postcopy cannot deal with concurrent discards, + * so it's special, as well as background snapshots. + */ + return ram_block_discard_is_disabled() || migration_in_incoming_postco= py() || + migration_in_bg_snapshot(); } =20 static void balloon_inflate_page(VirtIOBalloon *balloon, diff --git a/include/migration/misc.h b/include/migration/misc.h index bccc1b6b44..738675ef52 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -70,6 +70,8 @@ bool migration_in_postcopy_after_devices(MigrationState *= ); void migration_global_dump(Monitor *mon); /* True if incomming migration entered POSTCOPY_INCOMING_DISCARD */ bool migration_in_incoming_postcopy(void); +/* True if background snapshot is active */ +bool migration_in_bg_snapshot(void); =20 /* migration/block-dirty-bitmap.c */ void dirty_bitmap_mig_init(void); diff --git a/migration/migration.c b/migration/migration.c index 496cf6e17b..656d6249a6 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1976,6 +1976,14 @@ bool migration_in_incoming_postcopy(void) return ps >=3D POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END; } =20 +bool migration_in_bg_snapshot(void) +{ + MigrationState *s =3D migrate_get_current(); + + return migrate_background_snapshot() && + migration_is_setup_or_active(s->state); +} + bool migration_is_idle(void) { MigrationState *s =3D current_migration; --=20 2.25.1 From nobody Sat May 4 11:10:26 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=virtuozzo.com ARC-Seal: i=1; a=rsa-sha256; t=1616090633; cv=none; d=zohomail.com; s=zohoarc; b=LdXeCM91rKZWtL/PmqtdOkV8shydIA7Rc1rem6irxSRVAmVEsqR4a0H2DpO7Ygm4SV6aS5UHLmplf/QUKglALmlHLVUfND3KhjHYK6xOoccUpqFQQbA41lFBEbA17z14yTDWFoUrhgqqMOXkIGnBQgEMbdgyTQLgfCN6ukRQ29o= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1616090633; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=cvJuFppu7SmRAj2F1cKmCQtQ1pGH8gESyB0Znk8qimk=; b=higiWof9qodWEh9W2hPGbcg3y/jHvlx5nE+vNrp7vQkiIS8czOcpdKXS2HDVyxw3YQFefEbOL1KWPzElgI7w8COR5vlZ0I64oS0d5Ah4fqFbFwM446RfuFnHyJxiqtx5gbaxOwJ67Soz0CR5X94mV+PdnSo8nco665ZdBcjD7/s= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1616090633571812.4853419703846; Thu, 18 Mar 2021 11:03:53 -0700 (PDT) Received: from localhost ([::1]:43382 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMwzv-0001Zo-EZ for importer@patchew.org; Thu, 18 Mar 2021 14:03:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54002) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwlX-0006ez-1Q for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:48:59 -0400 Received: from relay.sw.ru ([185.231.240.75]:58296) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMwlA-0008Dw-OY for qemu-devel@nongnu.org; Thu, 18 Mar 2021 13:48:58 -0400 Received: from [192.168.15.248] (helo=andrey-MS-7B54.sw.ru) by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1lMwkX-003De5-TX; Thu, 18 Mar 2021 20:47:57 +0300 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=MIME-Version:Message-Id:Date:Subject:From: Content-Type; bh=cvJuFppu7SmRAj2F1cKmCQtQ1pGH8gESyB0Znk8qimk=; b=MmMru/V3vCu1 JwdCcuWS/t4ewlbKLQ07d+JZYrW14WNac8wJ0VtfWTrp4avHpDhsP1KtLl5GN9KC6TIEjbTT1NWT7 nVtQ6kB/DHh/zylaxp0FeTz40jfumvbgwBupGIPwZOiacQvPDz4RBz4LHOxLQxeanNnu5S6bOhuTR w487U=; From: Andrey Gruzdev To: qemu-devel@nongnu.org Cc: Den Lunev , Eric Blake , Paolo Bonzini , Juan Quintela , "Dr . David Alan Gilbert" , Markus Armbruster , Peter Xu , David Hildenbrand , Andrey Gruzdev Subject: [PATCH 3/3] migration: Pre-fault memory before starting background snasphot Date: Thu, 18 Mar 2021 20:46:11 +0300 Message-Id: <20210318174611.293520-4-andrey.gruzdev@virtuozzo.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> References: <20210318174611.293520-1-andrey.gruzdev@virtuozzo.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.gruzdev@virtuozzo.com; helo=relay.sw.ru X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @virtuozzo.com) Content-Type: text/plain; charset="utf-8" This commit solves the issue with userfault_fd WP feature that background snapshot is based on. For any never poluated or discarded memory page, the UFFDIO_WRITEPROTECT ioctl() would skip updating PTE for that page, thereby loosing WP setting for it. So we need to pre-fault pages for each RAM block to be protected before making a userfault_fd wr-protect ioctl(). Signed-off-by: Andrey Gruzdev --- migration/migration.c | 6 +++++ migration/ram.c | 51 +++++++++++++++++++++++++++++++++++++++++++ migration/ram.h | 1 + 3 files changed, 58 insertions(+) diff --git a/migration/migration.c b/migration/migration.c index 656d6249a6..496e88cbda 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -3872,6 +3872,12 @@ static void *bg_migration_thread(void *opaque) =20 update_iteration_initial_status(s); =20 + /* + * Prepare for tracking memory writes with UFFD-WP - populate + * RAM pages before protecting. + */ + ram_write_tracking_prepare(); + qemu_savevm_state_header(s->to_dst_file); qemu_savevm_state_setup(s->to_dst_file); =20 diff --git a/migration/ram.c b/migration/ram.c index 52537f14ac..825eb80030 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1560,6 +1560,57 @@ out: return ret; } =20 +/* + * ram_block_populate_pages: populate memory in the RAM block by reading + * an integer from the beginning of each page. + * + * Since it's solely used for userfault_fd WP feature, here we just + * hardcode page size to TARGET_PAGE_SIZE. + * + * @bs: RAM block to populate + */ +volatile int ram_block_populate_pages__tmp; +static void ram_block_populate_pages(RAMBlock *bs) +{ + ram_addr_t offset =3D 0; + int tmp =3D 0; + + for (char *ptr =3D (char *) bs->host; offset < bs->used_length; + ptr +=3D TARGET_PAGE_SIZE, offset +=3D TARGET_PAGE_SIZE) { + /* Try to do it without memory writes */ + tmp +=3D *(volatile int *) ptr; + } + /* Create dependency on 'extern volatile int' to avoid optimizing out = */ + ram_block_populate_pages__tmp +=3D tmp; +} + +/* + * ram_write_tracking_prepare: prepare for UFFD-WP memory tracking + */ +void ram_write_tracking_prepare(void) +{ + RAMBlock *bs; + + RCU_READ_LOCK_GUARD(); + + RAMBLOCK_FOREACH_NOT_IGNORED(bs) { + /* Nothing to do with read-only and MMIO-writable regions */ + if (bs->mr->readonly || bs->mr->rom_device) { + continue; + } + + /* + * Populate pages of the RAM block before enabling userfault_fd + * write protection. + * + * This stage is required since ioctl(UFFDIO_WRITEPROTECT) with + * UFFDIO_WRITEPROTECT_MODE_WP mode setting would silently skip + * pages with pte_none() entries in page table. + */ + ram_block_populate_pages(bs); + } +} + /* * ram_write_tracking_start: start UFFD-WP memory tracking * diff --git a/migration/ram.h b/migration/ram.h index 6378bb3ebc..4833e9fd5b 100644 --- a/migration/ram.h +++ b/migration/ram.h @@ -82,6 +82,7 @@ void colo_incoming_start_dirty_log(void); /* Background snapshot */ bool ram_write_tracking_available(void); bool ram_write_tracking_compatible(void); +void ram_write_tracking_prepare(void); int ram_write_tracking_start(void); void ram_write_tracking_stop(void); =20 --=20 2.25.1