All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Hildenbrand <david@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, qemu-devel@nongnu.org
Cc: "Laurent Vivier" <lvivier@redhat.com>,
	"Kevin Wolf" <kwolf@redhat.com>, "Thomas Huth" <thuth@redhat.com>,
	"Vladimir Sementsov-Ogievskiy" <v.sementsov-og@mail.ru>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	"John Snow" <jsnow@redhat.com>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Alberto Faria" <afaria@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Yanan Wang" <wangyanan55@huawei.com>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Hanna Reitz" <hreitz@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Fam Zheng" <fam@euphon.net>, "Eric Blake" <eblake@redhat.com>,
	sgarzare@redhat.com
Subject: Re: [RFC 2/8] numa: call ->ram_block_removed() in ram_block_notifer_remove()
Date: Wed, 30 Mar 2022 10:42:26 +0200	[thread overview]
Message-ID: <50b39fbd-c5f4-d080-3cc1-f6e4c27985fd@redhat.com> (raw)
In-Reply-To: <20220323111727.1100209-3-stefanha@redhat.com>

On 23.03.22 12:17, Stefan Hajnoczi wrote:
> When a RAMBlockNotifier is added, ->ram_block_added() is called with all
> existing RAMBlocks. There is no equivalent ->ram_block_removed() call
> when a RAMBlockNotifier is removed.
> 
> The util/vfio-helpers.c code (the sole user of RAMBlockNotifier) is fine
> with this asymmetry because it does not rely on RAMBlockNotifier for
> cleanup. It walks its internal list of DMA mappings and unmaps them by
> itself.
> 
> Future users of RAMBlockNotifier may not have an internal data structure
> that records added RAMBlocks so they will need ->ram_block_removed()
> callbacks.
> 
> This patch makes ram_block_notifier_remove() symmetric with respect to
> callbacks. Now util/vfio-helpers.c needs to unmap remaining DMA mappings
> after ram_block_notifier_remove() has been called. This is necessary
> since users like block/nvme.c may create additional DMA mappings that do
> not originate from the RAMBlockNotifier.
> 
> Cc: David Hildenbrand <david@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: David Hildenbrand <david@redhat.com>


-- 
Thanks,

David / dhildenb



  reply	other threads:[~2022-03-30  8:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-23 11:17 [RFC 0/8] blkio: add libblkio BlockDriver Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 1/8] blkio: add io_uring block driver using libblkio Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 2/8] numa: call ->ram_block_removed() in ram_block_notifer_remove() Stefan Hajnoczi
2022-03-30  8:42   ` David Hildenbrand [this message]
2022-03-23 11:17 ` [RFC 3/8] block: pass size to bdrv_unregister_buf() Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 4/8] block: add BDRV_REQ_REGISTERED_BUF request flag Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 5/8] block: add BlockRAMRegistrar Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 6/8] stubs: add memory_region_from_host() and memory_region_get_fd() Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 7/8] blkio: implement BDRV_REQ_REGISTERED_BUF optimization Stefan Hajnoczi
2022-03-29 15:24   ` Stefano Garzarella
2022-03-30 10:45     ` Stefan Hajnoczi
2022-03-23 11:17 ` [RFC 8/8] virtio-blk: use BDRV_REQ_REGISTERED_BUF optimization hint Stefan Hajnoczi
2022-03-29 15:27 ` [RFC 0/8] blkio: add libblkio BlockDriver Stefano Garzarella

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=50b39fbd-c5f4-d080-3cc1-f6e4c27985fd@redhat.com \
    --to=david@redhat.com \
    --cc=afaria@redhat.com \
    --cc=armbru@redhat.com \
    --cc=eblake@redhat.com \
    --cc=eduardo@habkost.net \
    --cc=f4bug@amsat.org \
    --cc=fam@euphon.net \
    --cc=hreitz@redhat.com \
    --cc=jsnow@redhat.com \
    --cc=kwolf@redhat.com \
    --cc=lvivier@redhat.com \
    --cc=mst@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-block@nongnu.org \
    --cc=qemu-devel@nongnu.org \
    --cc=sgarzare@redhat.com \
    --cc=stefanha@redhat.com \
    --cc=thuth@redhat.com \
    --cc=v.sementsov-og@mail.ru \
    --cc=wangyanan55@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.