From: David Vrabel <david.vrabel@citrix.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: xen-devel@lists.xensource.com, Tim Deegan <tim@xen.org>,
Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH RFC 0/3] introduce XENMEM_get_dma_buf and XENMEM_put_dma_buf
Date: Thu, 1 Aug 2013 10:41:06 +0100 [thread overview]
Message-ID: <51FA2D32.4050001@citrix.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1307311850010.4893@kaball.uk.xensource.com>
On 31/07/13 18:57, Stefano Stabellini wrote:
> Hi all,
> this patch series introduces two new hypercalls to allow autotranslate
> guests to allocate a contiguous buffer in machine addresses.
> The XENMEM_get_dma_buf returns the mfns and makes sure to pin the pages
> so that the hypervisor won't change their p2m mappings while in use.
> XENMEM_put_dma_buf simply unpins the pages.
Can you expand on what circumstances the hypervisor would otherwise
adjust the p2m? How has x86 avoided these problems?
> The implementation of XENMEM_put_dma_buf is missing, as it's actually
> unused.
>
> The page pinning is also missing from this series. I would appreciate
> feedback on the best way to implement it, especially on x86.
David
next prev parent reply other threads:[~2013-08-01 9:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-31 17:57 [PATCH RFC 0/3] introduce XENMEM_get_dma_buf and XENMEM_put_dma_buf Stefano Stabellini
2013-07-31 17:57 ` [PATCH RFC 1/3] xen/arm: implement steal_page Stefano Stabellini
2013-07-31 17:57 ` [PATCH RFC 2/3] xen: provide empty stubs for guest_physmap_(un)pin_range on arm and x86 Stefano Stabellini
2013-07-31 17:57 ` [PATCH RFC 3/3] xen: introduce XENMEM_get_dma_buf and XENMEM_put_dma_buf Stefano Stabellini
2013-08-01 9:41 ` David Vrabel [this message]
2013-08-01 14:55 ` [PATCH RFC 0/3] " Ian Campbell
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=51FA2D32.4050001@citrix.com \
--to=david.vrabel@citrix.com \
--cc=Ian.Campbell@citrix.com \
--cc=stefano.stabellini@eu.citrix.com \
--cc=tim@xen.org \
--cc=xen-devel@lists.xensource.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).