From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
robh@kernel.org, pawel.moll@arm.com,
Tom Lendacky <thomas.lendacky@amd.com>,
aik@ozlabs.ru, jasowang@redhat.com, cohuck@redhat.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, joe@perches.com,
"Rustad, Mark D" <mark.d.rustad@intel.com>,
david@gibson.dropbear.id.au, linuxppc-dev@lists.ozlabs.org,
elfring@users.sourceforge.net,
Anshuman Khandual <khandual@linux.vnet.ibm.com>
Subject: Re: [RFC V2] virtio: Add platform specific DMA API translation for virito devices
Date: Sat, 16 Jun 2018 11:07:24 +1000 [thread overview]
Message-ID: <1b4732c5015ee4377fef1de0270065174cde397a.camel@kernel.crashing.org> (raw)
In-Reply-To: <20180615091624.GA1064@infradead.org>
On Fri, 2018-06-15 at 02:16 -0700, Christoph Hellwig wrote:
> On Wed, Jun 13, 2018 at 11:11:01PM +1000, Benjamin Herrenschmidt wrote:
> > Actually ... the stuff in lib/dma-direct.c seems to be just it, no ?
> >
> > There's no cache flushing and there's no architecture hooks that I can
> > see other than the AMD security stuff which is probably fine.
> >
> > Or am I missing something ?
>
> You are missing the __phys_to_dma arch hook that allows architectures
> to adjust the dma address. Various systems have offsets, or even
> multiple banks with different offsets there. Most of them don't
> use the dma-direct code yet (working on it), but there are a few
> examples in the tree already.
Ok and on those systems, qemu will bypass said offset ? Maybe we could
just create a device DMA "flag" or (or use the attributes) to instruct
dma-direct to not use that for legacy virtio ?
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: robh@kernel.org, cohuck@redhat.com, pawel.moll@arm.com,
Tom Lendacky <thomas.lendacky@amd.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Ram Pai <linuxram@us.ibm.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, joe@perches.com,
"Rustad, Mark D" <mark.d.rustad@intel.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, elfring@users.sourceforge.net,
david@gibson.dropbear.id.au
Subject: Re: [RFC V2] virtio: Add platform specific DMA API translation for virito devices
Date: Sat, 16 Jun 2018 11:07:24 +1000 [thread overview]
Message-ID: <1b4732c5015ee4377fef1de0270065174cde397a.camel@kernel.crashing.org> (raw)
In-Reply-To: <20180615091624.GA1064@infradead.org>
On Fri, 2018-06-15 at 02:16 -0700, Christoph Hellwig wrote:
> On Wed, Jun 13, 2018 at 11:11:01PM +1000, Benjamin Herrenschmidt wrote:
> > Actually ... the stuff in lib/dma-direct.c seems to be just it, no ?
> >
> > There's no cache flushing and there's no architecture hooks that I can
> > see other than the AMD security stuff which is probably fine.
> >
> > Or am I missing something ?
>
> You are missing the __phys_to_dma arch hook that allows architectures
> to adjust the dma address. Various systems have offsets, or even
> multiple banks with different offsets there. Most of them don't
> use the dma-direct code yet (working on it), but there are a few
> examples in the tree already.
Ok and on those systems, qemu will bypass said offset ? Maybe we could
just create a device DMA "flag" or (or use the attributes) to instruct
dma-direct to not use that for legacy virtio ?
Cheers,
Ben.
next prev parent reply other threads:[~2018-06-16 1:09 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-22 6:33 [RFC V2] virtio: Add platform specific DMA API translation for virito devices Anshuman Khandual
2018-05-23 18:50 ` Michael S. Tsirkin
2018-05-23 18:50 ` Michael S. Tsirkin
2018-05-23 22:27 ` Benjamin Herrenschmidt
2018-05-23 22:27 ` Benjamin Herrenschmidt
2018-05-24 7:17 ` Christoph Hellwig
2018-05-24 7:17 ` Christoph Hellwig
2018-05-25 17:45 ` Michael S. Tsirkin
2018-05-28 23:48 ` Benjamin Herrenschmidt
2018-05-28 23:48 ` Benjamin Herrenschmidt
2018-05-28 23:56 ` Benjamin Herrenschmidt
2018-05-28 23:56 ` Benjamin Herrenschmidt
2018-05-29 14:03 ` Christoph Hellwig
2018-05-29 14:03 ` Christoph Hellwig
2018-05-29 22:13 ` Benjamin Herrenschmidt
2018-05-29 22:13 ` Benjamin Herrenschmidt
2018-05-25 17:45 ` Michael S. Tsirkin
2018-06-04 8:57 ` David Gibson
2018-06-04 8:57 ` David Gibson
2018-06-04 9:48 ` Benjamin Herrenschmidt
2018-06-04 9:48 ` Benjamin Herrenschmidt
2018-06-04 12:50 ` Michael S. Tsirkin
2018-06-04 12:50 ` Michael S. Tsirkin
2018-06-05 1:52 ` David Gibson
2018-06-05 1:52 ` David Gibson
2018-06-04 12:43 ` Michael S. Tsirkin
2018-06-04 12:55 ` Christoph Hellwig
2018-06-04 13:14 ` Benjamin Herrenschmidt
2018-06-04 13:14 ` Benjamin Herrenschmidt
2018-06-04 16:34 ` Michael S. Tsirkin
2018-06-04 16:34 ` Michael S. Tsirkin
2018-06-04 12:55 ` Christoph Hellwig
2018-06-04 13:11 ` Benjamin Herrenschmidt
2018-06-04 13:11 ` Benjamin Herrenschmidt
2018-06-04 16:21 ` Michael S. Tsirkin
2018-06-04 23:26 ` Benjamin Herrenschmidt
2018-06-04 23:26 ` Benjamin Herrenschmidt
2018-06-05 1:25 ` Michael S. Tsirkin
2018-06-05 1:25 ` Michael S. Tsirkin
2018-06-05 4:52 ` Christoph Hellwig
2018-06-05 4:52 ` Christoph Hellwig
2018-06-04 16:21 ` Michael S. Tsirkin
2018-06-04 12:43 ` Michael S. Tsirkin
2018-05-24 7:21 ` Ram Pai
2018-05-31 3:39 ` Anshuman Khandual
2018-05-31 17:43 ` Michael S. Tsirkin
2018-05-31 17:43 ` Michael S. Tsirkin
2018-06-07 5:23 ` Christoph Hellwig
2018-06-07 16:28 ` Michael S. Tsirkin
2018-06-08 6:36 ` Christoph Hellwig
2018-06-08 6:36 ` Christoph Hellwig
2018-06-13 13:49 ` Michael S. Tsirkin
2018-06-13 13:49 ` Michael S. Tsirkin
2018-06-11 2:39 ` Ram Pai
2018-06-11 3:28 ` Michael S. Tsirkin
2018-06-11 3:28 ` Michael S. Tsirkin
2018-06-11 3:34 ` Benjamin Herrenschmidt
2018-06-11 3:34 ` Benjamin Herrenschmidt
2018-06-13 14:23 ` Michael S. Tsirkin
2018-06-13 14:23 ` Michael S. Tsirkin
2018-06-11 3:29 ` Benjamin Herrenschmidt
2018-06-11 3:29 ` Benjamin Herrenschmidt
2018-06-13 7:41 ` Christoph Hellwig
2018-06-13 7:41 ` Christoph Hellwig
2018-06-13 12:25 ` Benjamin Herrenschmidt
2018-06-13 12:25 ` Benjamin Herrenschmidt
2018-06-13 13:11 ` Benjamin Herrenschmidt
2018-06-13 13:11 ` Benjamin Herrenschmidt
2018-06-15 9:16 ` Christoph Hellwig
2018-06-15 9:16 ` Christoph Hellwig
2018-06-16 1:07 ` Benjamin Herrenschmidt [this message]
2018-06-16 1:07 ` Benjamin Herrenschmidt
2018-06-13 13:59 ` Michael S. Tsirkin
2018-06-13 13:59 ` Michael S. Tsirkin
2018-06-13 14:03 ` Michael S. Tsirkin
2018-06-13 14:03 ` Michael S. Tsirkin
2018-06-07 16:28 ` Michael S. Tsirkin
2018-06-07 5:23 ` Christoph Hellwig
2018-05-31 3:39 ` Anshuman Khandual
-- strict thread matches above, loose matches on Subject: below --
2018-05-22 6:33 Anshuman Khandual
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