From: David Vrabel <david.vrabel@citrix.com>
To: "Paulina Szubarczyk" <paulinaszubarczyk@gmail.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Cc: sstabellini@kernel.org, wei.liu2@citrix.com,
George.Dunlap@eu.citrix.com, ian.jackson@eu.citrix.com,
P.Gawkowski@ii.pw.edu.pl, anthony.perard@citrix.com,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH RESEND 2/4] qdisk, hw/block/xen_disk: Removal of grant mapping
Date: Thu, 2 Jun 2016 11:22:45 +0100 [thread overview]
Message-ID: <575008F5.5040905@citrix.com> (raw)
In-Reply-To: <1464861464.12923.8.camel@localhost>
On 02/06/16 10:57, Paulina Szubarczyk wrote:
> On Thu, 2016-06-02 at 11:41 +0200, Roger Pau Monné wrote:
>> On Tue, May 31, 2016 at 06:44:56AM +0200, Paulina Szubarczyk wrote:
>>> Grant mapping related functions and variables are removed
>>> on behalf of grant copy operation introduced in following commits.
>>
>> As David says, you should not remove this before adding a suitable
>> replacement, or else you are breaking the build.
>>
>> Also, the grant map and unmap mode should be keep (we can talk about
>> removing persistent grants support), because there are gnttab devices out
>> there that only support grant map/unmap, but not grant copy IIRC.
>>
> Ok, so there should be a conditional path in this case, but is there a
> way to check if grant copy is supported?
> If not it might maybe be checked in run-time for example trying to issue
> grant copy and if it fails for the first time set that it is not
> supported and proceed with grant map?
You can try the IOCTL_GNTDEV_GRANT_COPY with a count of 0 which will
return success (0) if this ioctl is supported.
David
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next prev parent reply other threads:[~2016-06-02 10:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 4:44 [PATCH RESEND 0/4] qemu-qdisk: Replace grant map by grant copy Paulina Szubarczyk
2016-05-31 4:44 ` [PATCH RESEND 1/4] libs, gnttab, libxc: Interface for grant copy operation Paulina Szubarczyk
2016-05-31 9:25 ` David Vrabel
2016-06-01 7:45 ` Paulina Szubarczyk
2016-06-01 11:22 ` David Vrabel
2016-06-01 11:42 ` Paulina Szubarczyk
2016-06-02 9:37 ` Roger Pau Monné
2016-06-06 14:47 ` Wei Liu
2016-05-31 4:44 ` [PATCH RESEND 2/4] qdisk, hw/block/xen_disk: Removal of grant mapping Paulina Szubarczyk
2016-05-31 9:26 ` David Vrabel
2016-06-02 9:41 ` Roger Pau Monné
2016-06-02 9:57 ` Paulina Szubarczyk
2016-06-02 10:22 ` David Vrabel [this message]
2016-05-31 4:44 ` [PATCH RESEND 3/4] qdisk, hw/block/xen_disk: Perform grant copy instead of grant map Paulina Szubarczyk
2016-05-31 9:37 ` David Vrabel
2016-06-01 7:52 ` Paulina Szubarczyk
2016-06-01 11:15 ` David Vrabel
2016-06-02 13:47 ` Roger Pau Monné
2016-05-31 4:44 ` [PATCH RESEND 4/4] qemu-xen-dir/hw/block: Cache local buffers used in grant copy Paulina Szubarczyk
2016-06-02 14:19 ` Roger Pau Monné
2016-06-07 13:13 ` Paulina Szubarczyk
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