From: julien.grall@citrix•com (Julien Grall)
To: linux-arm-kernel@lists•infradead.org
Subject: [Xen-devel] [PATCH v2 09/20] xen/biomerge: Don't allow biovec to be merge when Linux is not using 4KB page
Date: Wed, 15 Jul 2015 10:56:50 +0200 [thread overview]
Message-ID: <55A62052.7020008@citrix.com> (raw)
In-Reply-To: <20150710191245.GA31063@l.oracle.com>
Hi Konrad,
On 10/07/2015 21:12, Konrad Rzeszutek Wilk wrote:
> On Thu, Jul 09, 2015 at 09:42:21PM +0100, Julien Grall wrote:
>> When Linux is using 64K page granularity, every page will be slipt in
>> multiple non-contiguous 4K MFN (page granularity of Xen).
>
> But you don't care about that on the Linux layer I think?
In general use case (i.e arch agnostic) we care about it. We don't want
to merge 2 biovec if they are not living on the same MFNs.
> As in, is there an SWIOTLB that does PFN to MFN and vice-versa
> translation?
>
> I thought that ARM guests are not exposed to the MFN<->PFN logic
> and trying to figure that out to not screw up the DMA engine
> on a PCIe device slurping up contingous MFNs which don't map
> to contingous PFNs?
I will let these 2 questions for Stefano. He knows better than me
swiotlb for ARM.
So far, I skipped swiotlb implementation for 64KB page granularity as
I'm not sure what to do when a page is split across multiple MFNs.
Although I don't think this can happen with this specific series as:
- The memory is a direct mapping so any Linux page is using contiguous
MFNs.
- Foreign mapping is using the 4KB of the Linux page. This is for an
easier implementation.
For the latter, I plan to work on using the Linux page to map multiple
foreign gfn. I have to talk with Stefano about it how to handle it.
Regards,
--
Julien Grall
next prev parent reply other threads:[~2015-07-15 8:56 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 20:42 [PATCH v2 00/20] xen/arm64: Add support for 64KB page Julien Grall
2015-07-09 20:42 ` [PATCH v2 01/20] xen: Add Xen specific page definition Julien Grall
2015-07-16 14:19 ` Stefano Stabellini
2015-07-16 14:52 ` Julien Grall
2015-07-24 9:28 ` [Xen-devel] " David Vrabel
2015-07-24 9:39 ` Julien Grall
2015-07-24 9:48 ` David Vrabel
2015-07-24 9:51 ` Julien Grall
2015-07-24 10:34 ` David Vrabel
2015-07-24 10:43 ` Ian Campbell
2015-07-24 13:03 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 02/20] xen: Introduce a function to split a Linux page into Xen page Julien Grall
2015-07-16 14:23 ` Stefano Stabellini
2015-07-16 14:54 ` [Xen-devel] " Julien Grall
2015-07-24 9:31 ` David Vrabel
2015-07-24 9:54 ` Julien Grall
2015-07-24 10:10 ` David Vrabel
2015-07-24 10:20 ` Julien Grall
2015-08-05 14:30 ` Julien Grall
2015-08-05 15:50 ` David Vrabel
2015-08-05 16:06 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 03/20] xen/grant: Introduce helpers to split a page into grant Julien Grall
2015-07-16 15:01 ` Stefano Stabellini
2015-07-16 16:07 ` Julien Grall
2015-07-17 13:10 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 04/20] xen/grant: Add helper gnttab_page_grant_foreign_access_ref Julien Grall
2015-07-16 15:05 ` Stefano Stabellini
2015-07-16 16:12 ` [Xen-devel] " Julien Grall
2015-07-24 9:35 ` David Vrabel
2015-07-09 20:42 ` [PATCH v2 05/20] block/xen-blkfront: Split blkif_queue_request in 2 Julien Grall
2015-07-21 9:54 ` Roger Pau Monné
2015-07-21 11:12 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 06/20] block/xen-blkfront: Store a page rather a pfn in the grant structure Julien Grall
2015-07-16 15:11 ` Stefano Stabellini
2015-07-23 17:18 ` Julien Grall
2015-07-21 10:16 ` Roger Pau Monné
2015-07-21 11:19 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 07/20] block/xen-blkfront: split get_grant in 2 Julien Grall
2015-07-21 10:30 ` Roger Pau Monné
2015-07-21 13:03 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 08/20] net/xen-netback: xenvif_gop_frag_copy: move GSO check out of the loop Julien Grall
2015-07-09 20:42 ` [PATCH v2 09/20] xen/biomerge: Don't allow biovec to be merge when Linux is not using 4KB page Julien Grall
2015-07-10 19:12 ` Konrad Rzeszutek Wilk
2015-07-15 8:56 ` Julien Grall [this message]
2015-07-16 15:33 ` Stefano Stabellini
2015-07-16 16:15 ` [Xen-devel] " Julien Grall
2015-07-16 18:30 ` Konrad Rzeszutek Wilk
2015-07-17 13:20 ` Stefano Stabellini
2015-07-17 14:44 ` Julien Grall
2015-07-17 14:45 ` Stefano Stabellini
2015-07-17 14:46 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 10/20] xen/xenbus: Use Xen page definition Julien Grall
2015-07-16 15:35 ` Stefano Stabellini
2015-07-24 9:49 ` David Vrabel
2015-07-09 20:42 ` [PATCH v2 11/20] tty/hvc: xen: Use xen " Julien Grall
2015-07-16 15:36 ` Stefano Stabellini
2015-07-24 9:52 ` David Vrabel
2015-07-09 20:42 ` [PATCH v2 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux Julien Grall
2015-07-17 14:03 ` Stefano Stabellini
2015-07-17 14:32 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 13/20] xen/events: fifo: Make it running on 64KB granularity Julien Grall
2015-07-16 15:43 ` Stefano Stabellini
2015-07-16 16:18 ` [Xen-devel] " Julien Grall
2015-07-17 13:06 ` Stefano Stabellini
2015-07-24 10:36 ` David Vrabel
2015-08-06 15:43 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 14/20] xen/grant-table: " Julien Grall
2015-07-16 15:47 ` Stefano Stabellini
2015-07-16 16:23 ` [Xen-devel] " Julien Grall
2015-07-17 13:37 ` Stefano Stabellini
2015-07-09 20:42 ` [PATCH v2 15/20] block/xen-blkfront: Make it running on 64KB page granularity Julien Grall
2015-07-21 11:06 ` Roger Pau Monné
2015-07-21 13:07 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 16/20] block/xen-blkback: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 17/20] net/xen-netfront: " Julien Grall
2015-07-20 17:26 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 18/20] net/xen-netback: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 19/20] xen/privcmd: Add support for Linux " Julien Grall
2015-07-13 20:13 ` Boris Ostrovsky
2015-07-13 22:05 ` Julien Grall
2015-07-14 15:28 ` Boris Ostrovsky
2015-07-14 15:37 ` Julien Grall
2015-07-16 17:12 ` Stefano Stabellini
2015-07-16 17:16 ` Stefano Stabellini
2015-07-17 12:50 ` [Xen-devel] " Julien Grall
2015-07-09 20:42 ` [PATCH v2 20/20] arm/xen: Add support for " Julien Grall
2015-07-20 17:54 ` [Xen-devel] [PATCH v2 00/20] xen/arm64: Add support for 64KB page Julien Grall
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