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David Alan Gilbert" , Markus Armbruster , David Hildenbrand References: <20210319145249.425189-1-andrey.gruzdev@virtuozzo.com> <20210323222155.GA219069@xz-x1> From: Andrey Gruzdev Message-ID: <65f1ebcd-fac9-0923-33e7-889946066b40@virtuozzo.com> Date: Wed, 24 Mar 2021 11:09:27 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.2 In-Reply-To: <20210323222155.GA219069@xz-x1> Content-Type: multipart/alternative; boundary="------------1553B96A13748EC0C750010F" Content-Language: en-US X-Originating-IP: [95.165.26.68] X-ClientProxiedBy: AM9P195CA0007.EURP195.PROD.OUTLOOK.COM (2603:10a6:20b:21f::12) To VI1PR08MB3375.eurprd08.prod.outlook.com (2603:10a6:803:87::29) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.64] (95.165.26.68) by AM9P195CA0007.EURP195.PROD.OUTLOOK.COM (2603:10a6:20b:21f::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.18 via Frontend Transport; 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envelope-from=andrey.gruzdev@virtuozzo.com; helo=EUR01-VE1-obe.outbound.protection.outlook.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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, HTML_MESSAGE=0.001, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --------------1553B96A13748EC0C750010F Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit On 24.03.2021 01:21, Peter Xu wrote: > On Fri, Mar 19, 2021 at 05:52:46PM +0300, Andrey Gruzdev wrote: >> Changes v0->v1: >> * Using qemu_real_host_page_size instead of TARGET_PAGE_SIZE for host >> page size in ram_block_populate_pages() >> * More elegant implementation of ram_block_populate_pages() >> >> This patch series contains: >> * Fix to the issue with occasionally truncated non-iterable device state >> * Solution to compatibility issues with virtio-balloon device >> * Fix to the issue when discarded or never populated pages miss UFFD >> write protection and get into migration stream in dirty state >> >> Andrey Gruzdev (3): >> migration: Fix missing qemu_fflush() on buffer file in >> bg_migration_thread >> migration: Inhibit virtio-balloon for the duration of background >> snapshot >> migration: Pre-fault memory before starting background snasphot > Unless Andrey would like to respin a new version, this version looks good to me > (I don't think the adding new helper issue in patch 1 is a blocker): > > Reviewed-by: Peter Xu Thanks. > I'm also looking into introducing UFFD_FEATURE_WP_UNALLOCATED so as to > wr-protect page holes too for a uffd-wp region when the feature bit is set. > With that feature we should be able to avoid pre-fault as what we do in the > last patch of this series. However even if that can work out, we'll still need > this for old kernel anyways. I'm curious this new feature is based on adding wr-protection at the level of VMAs, so we won't miss write faults for missing pages? > Thanks, > --------------1553B96A13748EC0C750010F Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit
On 24.03.2021 01:21, Peter Xu wrote:
On Fri, Mar 19, 2021 at 05:52:46PM +0300, Andrey Gruzdev wrote:

Changes v0->v1:
 * Using qemu_real_host_page_size instead of TARGET_PAGE_SIZE for host
   page size in ram_block_populate_pages()
 * More elegant implementation of ram_block_populate_pages()

This patch series contains:
 * Fix to the issue with occasionally truncated non-iterable device state
 * Solution to compatibility issues with virtio-balloon device
 * Fix to the issue when discarded or never populated pages miss UFFD
   write protection and get into migration stream in dirty state

Andrey Gruzdev (3):
  migration: Fix missing qemu_fflush() on buffer file in
    bg_migration_thread
  migration: Inhibit virtio-balloon for the duration of background
    snapshot
  migration: Pre-fault memory before starting background snasphot

Unless Andrey would like to respin a new version, this version looks good to me
(I don't think the adding new helper issue in patch 1 is a blocker):

Reviewed-by: Peter Xu <peterx@redhat.com>

Thanks.

I'm also looking into introducing UFFD_FEATURE_WP_UNALLOCATED so as to
wr-protect page holes too for a uffd-wp region when the feature bit is set.
With that feature we should be able to avoid pre-fault as what we do in the
last patch of this series.  However even if that can work out, we'll still need
this for old kernel anyways.

I'm curious this new feature is based on adding wr-protection at the level of VMAs,
so we won't miss write faults for missing pages?

Thanks,


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