From: David Woodhouse <dwmw2@infradead.org>
To: Vikram Garhwal <vikram.garhwal@amd.com>, qemu-devel@nongnu.org
Cc: sstabellini@kernel.org, jgross@suse.com
Subject: Re: [QEMU][PATCHv2 0/8] Xen: support grant mappings.
Date: Thu, 26 Oct 2023 17:12:28 +0100 [thread overview]
Message-ID: <48b53eefdbcd4e61d09acfd2532ea8721376d0de.camel@infradead.org> (raw)
In-Reply-To: <20231025212422.30371-1-vikram.garhwal@amd.com>
[-- Attachment #1: Type: text/plain, Size: 1325 bytes --]
On Wed, 2023-10-25 at 14:24 -0700, Vikram Garhwal wrote:
> Hi,
> This patch series add support for grant mappings as a pseudo RAM region for Xen.
>
> Enabling grant mappings patches(first 6) are written by Juergen in 2021.
>
> QEMU Virtio device provides an emulated backends for Virtio frontned devices
> in Xen.
> Please set "iommu_platform=on" option when invoking QEMU. As this will set
> VIRTIO_F_ACCESS_PLATFORM feature which will be used by virtio frontend in Xen
> to know whether backend supports grants or not.
I don't really understand what's going on here. The subject of the
cover letter certainly doesn't help me, because we *already* support
grant mappings under Xen, don't we?
I found
https://static.linaro.org/connect/lvc21/presentations/lvc21-314.pdf but
I think it's a bit out of date; the decision about how to handle grant
mappings for virtio devices is still 'TBD'.
Can you talk me through the process of what happens when a guest wants
to a virtio device to initiate 'DMA' to one of its pages? I assume it
starts by creating a grant mapping, and then taking the gntref and...
then what?
I don't see any changes to the virtio devices themselves in this
series; are we doing something that will make it work by magic? If so,
it might be useful to explain that magic...
[-- Attachment #2: smime.p7s --]
[-- Type: application/pkcs7-signature, Size: 5965 bytes --]
next prev parent reply other threads:[~2023-10-26 16:13 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-25 21:24 [QEMU][PATCHv2 0/8] Xen: support grant mappings Vikram Garhwal
2023-10-25 21:24 ` [QEMU][PATCHv2 1/8] xen: when unplugging emulated devices skip virtio devices Vikram Garhwal
2023-10-25 23:22 ` David Woodhouse
2023-10-26 1:23 ` Stefano Stabellini
2023-10-26 15:45 ` David Woodhouse
2023-10-26 17:13 ` Vikram Garhwal
2023-10-25 21:24 ` [QEMU][PATCHv2 2/8] softmmu: physmem: Split ram_block_add() Vikram Garhwal
2023-10-26 1:25 ` Stefano Stabellini
2023-10-25 21:24 ` [QEMU][PATCHv2 3/8] xen: add pseudo RAM region for grant mappings Vikram Garhwal
2023-10-26 1:27 ` Stefano Stabellini
2023-10-25 21:24 ` [QEMU][PATCHv2 4/8] softmmu: let qemu_map_ram_ptr() use qemu_ram_ptr_length() Vikram Garhwal
2023-10-26 1:28 ` Stefano Stabellini
2023-10-25 21:24 ` [QEMU][PATCHv2 5/8] xen: let xen_ram_addr_from_mapcache() return -1 in case of not found entry Vikram Garhwal
2023-10-25 21:24 ` [QEMU][PATCHv2 6/8] memory: add MemoryRegion map and unmap callbacks Vikram Garhwal
2023-10-25 21:24 ` [QEMU][PATCHv2 7/8] xen: add map and unmap callbacks for grant region Vikram Garhwal
2023-10-26 1:32 ` Stefano Stabellini
2023-10-26 4:35 ` Vikram Garhwal
2023-10-25 21:24 ` [QEMU][PATCHv2 8/8] hw: arm: Add grant mapping Vikram Garhwal
2023-10-26 16:12 ` David Woodhouse [this message]
2023-10-26 18:07 ` [QEMU][PATCHv2 0/8] Xen: support grant mappings Stefano Stabellini
2023-10-26 20:15 ` David Woodhouse
2023-10-26 20:36 ` Stefano Stabellini
2023-10-26 20:44 ` David Woodhouse
2023-10-26 20:56 ` Stefano Stabellini
2023-10-27 5:27 ` Juergen Gross
2023-11-13 20:24 ` David Woodhouse
2023-11-14 6:19 ` Juergen Gross
2023-11-14 20:58 ` Stefano Stabellini
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=48b53eefdbcd4e61d09acfd2532ea8721376d0de.camel@infradead.org \
--to=dwmw2@infradead.org \
--cc=jgross@suse.com \
--cc=qemu-devel@nongnu.org \
--cc=sstabellini@kernel.org \
--cc=vikram.garhwal@amd.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).