From: "Jürgen Groß" <jgross@suse.com>
To: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v2] xen: Add RING_COPY_RESPONSE()
Date: Thu, 4 Feb 2021 12:10:13 +0100 [thread overview]
Message-ID: <b37ac2f6-312e-51b7-1606-8e487430d749@suse.com> (raw)
In-Reply-To: <20210128155030.1831483-1-marmarek@invisiblethingslab.com>
[-- Attachment #1.1.1: Type: text/plain, Size: 864 bytes --]
On 28.01.21 16:50, Marek Marczykowski-Górecki wrote:
> Using RING_GET_RESPONSE() on a shared ring is easy to use incorrectly
> (i.e., by not considering that the other end may alter the data in the
> shared ring while it is being inspected). Safe usage of a response
> generally requires taking a local copy.
>
> Provide a RING_COPY_RESPONSE() macro to use instead of
> RING_GET_RESPONSE() and an open-coded memcpy(). This takes care of
> ensuring that the copy is done correctly regardless of any possible
> compiler optimizations.
>
> Use a volatile source to prevent the compiler from reordering or
> omitting the copy.
>
> This generalizes similar RING_COPY_REQUEST() macro added in 3f20b8def0.
>
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
[-- Attachment #1.1.2: OpenPGP_0xB0DE9DD628BF132F.asc --]
[-- Type: application/pgp-keys, Size: 3135 bytes --]
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]
prev parent reply other threads:[~2021-02-04 11:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 15:50 [PATCH v2] xen: Add RING_COPY_RESPONSE() Marek Marczykowski-Górecki
2021-02-04 11:10 ` Jürgen Groß [this message]
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=b37ac2f6-312e-51b7-1606-8e487430d749@suse.com \
--to=jgross@suse.com \
--cc=marmarek@invisiblethingslab.com \
--cc=xen-devel@lists.xenproject.org \
/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).