From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-1541-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 2BB229863C8 for ; Fri, 27 Nov 2020 11:02:46 +0000 (UTC) Date: Fri, 27 Nov 2020 12:02:26 +0100 From: Cornelia Huck Message-ID: <20201127120226.100f112a.cohuck@redhat.com> In-Reply-To: <97ef1bc6-3c6d-b2d2-8d26-4fcb69cafc1b@redhat.com> References: <20201116191629.47661-1-david@redhat.com> <20201120161330.740d694e.cohuck@redhat.com> <97ef1bc6-3c6d-b2d2-8d26-4fcb69cafc1b@redhat.com> MIME-Version: 1.0 Subject: Re: [virtio-comment] Re: [PATCH v1] virtio-mem: minor clarification regarding read-access to unplugged blocks Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit To: David Hildenbrand Cc: virtio-comment@lists.oasis-open.org, teawater , Marek Kedzierski , "Michael S . Tsirkin" List-ID: On Fri, 27 Nov 2020 11:39:50 +0100 David Hildenbrand wrote: > On 20.11.20 16:13, Cornelia Huck wrote: > > On Mon, 16 Nov 2020 20:16:29 +0100 > > David Hildenbrand wrote: > > > >> Let's clarify that we don't expect all DMA to work with unplugged blocks. > >> We really only give guarantees when reading from unplugged memory blocks > >> via the CPU, e.g., as done by Linux when creating a system dump via > >> kdump: the new kernel will copy the content of the old (crashed) kernel > >> via the CPU to user space, from where it will find its final destination > >> inside the dump file. Note that dumping via makedumpfile under Linux will > >> avoid reading unplugged blocks completely. > >> > >> This is a preparation for device passthrough to VMs, whereby such > >> dedicated devices might not be able to read from unplugged memory blocks. > >> > >> Let's document that this scenario is possible, and why this handling is > >> in place at all. > >> > >> Cc: teawater > >> Cc: Marek Kedzierski > >> Cc: Michael S. Tsirkin > >> Cc: Cornelia Huck > >> Signed-off-by: David Hildenbrand > >> --- > >> virtio-mem.tex | 9 +++++++-- > >> 1 file changed, 7 insertions(+), 2 deletions(-) > > > > Looks reasonable to me. > > > > Acked-by: Cornelia Huck > > Thanks! > > I assume I'll need a github issue etc. to get this in, right? > Yes; just open the issue, point to this patch in the archives, and reply with the issue here. (I don't think this is trivial enough to push without voting.) This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/