From: "Michael S. Tsirkin" <mst@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Gregory Haskins <gregory.haskins@gmail.com>,
Avi Kivity <avi@redhat.com>,
"Ira W. Snyder" <iws@ovro.caltech.edu>,
netdev@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, mingo@elte.hu, linux-mm@kvack.org,
akpm@linux-foundation.org, hpa@zytor.com,
Rusty Russell <rusty@rustcorp.com.au>,
s.hetze@linux-ag.com, alacrityvm-devel@lists.sourceforge.net
Subject: Re: [PATCHv5 3/3] vhost_net: a kernel-level virtio server
Date: Wed, 16 Sep 2009 18:13:29 +0300 [thread overview]
Message-ID: <20090916151329.GC5513@redhat.com> (raw)
In-Reply-To: <200909161657.42628.arnd@arndb.de>
On Wed, Sep 16, 2009 at 04:57:42PM +0200, Arnd Bergmann wrote:
> On Tuesday 15 September 2009, Michael S. Tsirkin wrote:
> > Userspace in x86 maps a PCI region, uses it for communication with ppc?
>
> This might have portability issues. On x86 it should work, but if the
> host is powerpc or similar, you cannot reliably access PCI I/O memory
> through copy_tofrom_user but have to use memcpy_toio/fromio or readl/writel
> calls, which don't work on user pointers.
>
> Specifically on powerpc, copy_from_user cannot access unaligned buffers
> if they are on an I/O mapping.
>
> Arnd <><
We are talking about doing this in userspace, not in kernel.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Gregory Haskins <gregory.haskins@gmail.com>,
Avi Kivity <avi@redhat.com>,
"Ira W. Snyder" <iws@ovro.caltech.edu>,
netdev@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, mingo@elte.hu, linux-mm@kvack.org,
akpm@linux-foundation.org, hpa@zytor.com,
Rusty Russell <rusty@rustcorp.com.au>,
s.hetze@linux-ag.com, alacrityvm-devel@lists.sourceforge.net
Subject: Re: [PATCHv5 3/3] vhost_net: a kernel-level virtio server
Date: Wed, 16 Sep 2009 18:13:29 +0300 [thread overview]
Message-ID: <20090916151329.GC5513@redhat.com> (raw)
In-Reply-To: <200909161657.42628.arnd@arndb.de>
On Wed, Sep 16, 2009 at 04:57:42PM +0200, Arnd Bergmann wrote:
> On Tuesday 15 September 2009, Michael S. Tsirkin wrote:
> > Userspace in x86 maps a PCI region, uses it for communication with ppc?
>
> This might have portability issues. On x86 it should work, but if the
> host is powerpc or similar, you cannot reliably access PCI I/O memory
> through copy_tofrom_user but have to use memcpy_toio/fromio or readl/writel
> calls, which don't work on user pointers.
>
> Specifically on powerpc, copy_from_user cannot access unaligned buffers
> if they are on an I/O mapping.
>
> Arnd <><
We are talking about doing this in userspace, not in kernel.
--
MST
--
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next prev parent reply other threads:[~2009-09-16 15:16 UTC|newest]
Thread overview: 230+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1251388414.git.mst@redhat.com>
2009-08-27 16:06 ` [PATCHv5 1/3] mm: export use_mm/unuse_mm to modules Michael S. Tsirkin
2009-08-27 16:06 ` Michael S. Tsirkin
2009-08-27 16:06 ` Michael S. Tsirkin
2009-08-28 15:31 ` Gregory Haskins
2009-08-28 15:31 ` Gregory Haskins
2009-08-27 16:06 ` Michael S. Tsirkin
2009-08-27 16:07 ` [PATCHv5 2/3] mm: reduce atomic use on use_mm fast path Michael S. Tsirkin
2009-08-27 16:07 ` Michael S. Tsirkin
2009-08-27 16:07 ` Michael S. Tsirkin
2009-08-27 16:07 ` Michael S. Tsirkin
2009-08-27 16:07 ` [PATCHv5 3/3] vhost_net: a kernel-level virtio server Michael S. Tsirkin
2009-08-27 16:07 ` Michael S. Tsirkin
2009-08-27 16:07 ` Michael S. Tsirkin
2009-09-03 18:39 ` Ira W. Snyder
2009-09-03 18:39 ` Ira W. Snyder
2009-09-03 18:39 ` Ira W. Snyder
2009-09-07 10:15 ` Michael S. Tsirkin
2009-09-07 10:15 ` Michael S. Tsirkin
2009-09-08 17:20 ` Ira W. Snyder
2009-09-08 17:20 ` Ira W. Snyder
2009-09-08 20:14 ` Michael S. Tsirkin
2009-09-08 20:14 ` Michael S. Tsirkin
2009-09-08 20:14 ` Michael S. Tsirkin
2009-09-11 15:17 ` Xin, Xiaohui
2009-09-11 15:17 ` Xin, Xiaohui
2009-09-13 5:46 ` Michael S. Tsirkin
2009-09-13 5:46 ` Michael S. Tsirkin
2009-09-13 5:46 ` Michael S. Tsirkin
2009-09-14 5:57 ` Xin, Xiaohui
2009-09-14 5:57 ` Xin, Xiaohui
2009-09-14 5:57 ` Xin, Xiaohui
2009-09-14 7:05 ` Michael S. Tsirkin
2009-09-14 7:05 ` Michael S. Tsirkin
2009-09-14 7:05 ` Michael S. Tsirkin
2009-09-11 15:17 ` Xin, Xiaohui
2009-09-11 16:00 ` Gregory Haskins
2009-09-11 16:14 ` Gregory Haskins
2009-09-11 16:14 ` Gregory Haskins
2009-09-13 12:01 ` Michael S. Tsirkin
2009-09-13 12:01 ` Michael S. Tsirkin
2009-09-13 12:01 ` Michael S. Tsirkin
2009-09-14 16:08 ` Gregory Haskins
2009-09-14 16:47 ` Michael S. Tsirkin
2009-09-14 16:47 ` Michael S. Tsirkin
2009-09-14 19:14 ` Gregory Haskins
2009-09-14 19:14 ` Gregory Haskins
2009-09-15 12:35 ` Avi Kivity
2009-09-15 12:35 ` Avi Kivity
2009-09-15 12:35 ` Avi Kivity
2009-09-15 13:03 ` Gregory Haskins
2009-09-15 13:25 ` Avi Kivity
2009-09-15 13:25 ` Avi Kivity
2009-09-15 13:50 ` Gregory Haskins
2009-09-15 14:28 ` Michael S. Tsirkin
2009-09-15 14:28 ` Michael S. Tsirkin
2009-09-15 14:28 ` Michael S. Tsirkin
2009-09-15 15:03 ` Avi Kivity
2009-09-15 15:03 ` Avi Kivity
2009-09-15 15:03 ` Avi Kivity
2009-09-15 20:08 ` Gregory Haskins
2009-09-15 20:40 ` Michael S. Tsirkin
2009-09-15 20:40 ` Michael S. Tsirkin
2009-09-15 20:40 ` Michael S. Tsirkin
2009-09-15 20:43 ` Gregory Haskins
2009-09-15 21:25 ` Michael S. Tsirkin
2009-09-15 21:25 ` Michael S. Tsirkin
2009-09-15 21:39 ` Gregory Haskins
2009-09-15 21:39 ` Gregory Haskins
2009-09-15 21:38 ` Michael S. Tsirkin
2009-09-15 21:38 ` Michael S. Tsirkin
2009-09-15 21:55 ` Gregory Haskins
2009-09-15 21:55 ` Gregory Haskins
2009-09-15 21:38 ` Michael S. Tsirkin
2009-09-16 14:57 ` Arnd Bergmann
2009-09-16 14:57 ` Arnd Bergmann
2009-09-16 14:57 ` Arnd Bergmann
2009-09-16 15:13 ` Michael S. Tsirkin [this message]
2009-09-16 15:13 ` Michael S. Tsirkin
2009-09-16 15:22 ` Arnd Bergmann
2009-09-16 15:22 ` Arnd Bergmann
2009-09-16 16:08 ` Michael S. Tsirkin
2009-09-16 16:08 ` Michael S. Tsirkin
2009-09-16 16:08 ` Michael S. Tsirkin
2009-09-16 15:22 ` Arnd Bergmann
2009-09-16 15:13 ` Michael S. Tsirkin
2009-09-15 21:25 ` Michael S. Tsirkin
2009-09-15 20:43 ` Gregory Haskins
2009-09-16 8:23 ` Avi Kivity
2009-09-16 8:23 ` Avi Kivity
2009-09-16 8:23 ` Avi Kivity
2009-09-16 11:44 ` Gregory Haskins
2009-09-16 13:05 ` Avi Kivity
2009-09-16 13:05 ` Avi Kivity
2009-09-16 13:05 ` Avi Kivity
2009-09-16 14:10 ` Gregory Haskins
2009-09-16 14:10 ` Gregory Haskins
2009-09-16 15:59 ` Avi Kivity
2009-09-16 15:59 ` Avi Kivity
2009-09-16 15:59 ` Avi Kivity
2009-09-16 19:22 ` Gregory Haskins
2009-09-16 19:22 ` Gregory Haskins
2009-09-16 21:00 ` Avi Kivity
2009-09-16 21:00 ` Avi Kivity
2009-09-16 21:00 ` Avi Kivity
2009-09-17 3:11 ` Gregory Haskins
2009-09-17 3:11 ` Gregory Haskins
2009-09-17 7:49 ` Avi Kivity
2009-09-17 7:49 ` Avi Kivity
2009-09-17 7:49 ` Avi Kivity
2009-09-17 14:16 ` Javier Guerra
2009-09-17 14:16 ` Javier Guerra
2009-09-17 14:16 ` Javier Guerra
2009-09-21 21:43 ` Ira W. Snyder
2009-09-21 21:43 ` Ira W. Snyder
2009-09-22 9:43 ` Avi Kivity
2009-09-22 9:43 ` Avi Kivity
2009-09-22 9:43 ` Avi Kivity
2009-09-22 15:25 ` Ira W. Snyder
2009-09-22 15:25 ` Ira W. Snyder
2009-09-22 15:56 ` Avi Kivity
2009-09-22 15:56 ` Avi Kivity
2009-09-22 15:56 ` Avi Kivity
2009-09-22 15:25 ` Ira W. Snyder
2009-09-23 14:26 ` Gregory Haskins
2009-09-23 14:26 ` Gregory Haskins
2009-09-23 14:37 ` Avi Kivity
2009-09-23 14:37 ` Avi Kivity
2009-09-23 14:37 ` Avi Kivity
2009-09-23 15:10 ` Gregory Haskins
2009-09-23 15:10 ` Gregory Haskins
2009-09-23 17:58 ` Gregory Haskins
2009-09-23 17:58 ` Gregory Haskins
2009-09-23 19:37 ` Avi Kivity
2009-09-23 19:37 ` Avi Kivity
2009-09-23 21:15 ` Gregory Haskins
2009-09-23 21:15 ` Gregory Haskins
2009-09-24 7:18 ` Avi Kivity
2009-09-24 7:18 ` Avi Kivity
2009-09-24 7:18 ` Avi Kivity
2009-09-24 18:03 ` Gregory Haskins
2009-09-24 18:03 ` Gregory Haskins
2009-09-25 8:22 ` Avi Kivity
2009-09-25 8:22 ` Avi Kivity
2009-09-25 8:22 ` Avi Kivity
2009-09-25 21:32 ` Gregory Haskins
2009-09-25 21:32 ` Gregory Haskins
2009-09-27 9:43 ` Avi Kivity
2009-09-27 9:43 ` Avi Kivity
2009-09-27 9:43 ` Avi Kivity
2009-09-30 20:04 ` Gregory Haskins
2009-10-01 8:34 ` Avi Kivity
2009-10-01 8:34 ` Avi Kivity
2009-10-01 8:34 ` Avi Kivity
2009-10-01 8:34 ` Avi Kivity
2009-10-01 9:28 ` Michael S. Tsirkin
2009-10-01 9:28 ` Michael S. Tsirkin
2009-10-01 9:28 ` Michael S. Tsirkin
2009-10-01 19:24 ` Gregory Haskins
2009-10-01 19:24 ` Gregory Haskins
2009-10-03 10:00 ` Avi Kivity
2009-10-03 10:00 ` Avi Kivity
2009-10-03 10:00 ` Avi Kivity
2009-09-30 20:04 ` Gregory Haskins
2009-09-24 19:27 ` Ira W. Snyder
2009-09-24 19:27 ` Ira W. Snyder
2009-09-24 19:27 ` Ira W. Snyder
2009-09-25 7:43 ` Avi Kivity
2009-09-25 7:43 ` Avi Kivity
2009-09-25 7:43 ` Avi Kivity
2009-09-24 8:03 ` Avi Kivity
2009-09-24 8:03 ` Avi Kivity
2009-09-24 18:04 ` Gregory Haskins
2009-09-24 18:04 ` Gregory Haskins
2009-09-24 8:03 ` Avi Kivity
2009-09-23 19:37 ` Avi Kivity
2009-09-21 21:43 ` Ira W. Snyder
2009-09-17 3:57 ` Michael S. Tsirkin
2009-09-17 3:57 ` Michael S. Tsirkin
2009-09-17 3:57 ` Michael S. Tsirkin
2009-09-17 4:13 ` Gregory Haskins
2009-09-17 4:13 ` Gregory Haskins
2009-09-16 14:10 ` Gregory Haskins
2009-09-16 11:44 ` Gregory Haskins
2009-09-15 20:08 ` Gregory Haskins
2009-09-15 13:50 ` Gregory Haskins
2009-09-15 13:25 ` Avi Kivity
2009-09-15 13:03 ` Gregory Haskins
2009-09-15 12:32 ` Avi Kivity
2009-09-15 12:32 ` Avi Kivity
2009-09-15 12:32 ` Avi Kivity
2009-09-14 16:47 ` Michael S. Tsirkin
2009-09-14 16:53 ` Michael S. Tsirkin
2009-09-14 16:53 ` Michael S. Tsirkin
2009-09-14 16:53 ` Michael S. Tsirkin
2009-09-14 19:28 ` Gregory Haskins
2009-09-14 19:28 ` Gregory Haskins
2009-09-14 16:08 ` Gregory Haskins
2009-09-11 16:00 ` Gregory Haskins
2009-09-08 17:20 ` Ira W. Snyder
2009-09-07 10:15 ` Michael S. Tsirkin
2009-09-25 17:01 ` Ira W. Snyder
2009-09-25 17:01 ` Ira W. Snyder
2009-09-27 7:43 ` Michael S. Tsirkin
2009-09-27 7:43 ` Michael S. Tsirkin
2009-09-27 7:43 ` Michael S. Tsirkin
2009-09-25 17:01 ` Ira W. Snyder
2009-08-27 16:07 ` Michael S. Tsirkin
[not found] <E88DD564E9DC5446A76B2B47C3BCCA150219600F9B@pdsmsx503.ccr.corp.intel.com>
2009-08-31 11:42 ` Xin, Xiaohui
2009-08-31 11:42 ` Xin, Xiaohui
2009-08-31 11:42 ` Xin, Xiaohui
2009-08-31 11:42 ` Xin, Xiaohui
2009-08-31 11:42 ` Xin, Xiaohui
2009-08-31 15:23 ` Arnd Bergmann
2009-08-31 15:23 ` Arnd Bergmann
2009-09-01 14:58 ` Xin, Xiaohui
2009-09-01 14:58 ` Xin, Xiaohui
2009-09-01 14:58 ` Xin, Xiaohui
2009-08-31 15:23 ` Arnd Bergmann
2009-08-31 17:52 ` Avi Kivity
2009-08-31 17:52 ` Avi Kivity
2009-08-31 17:52 ` Avi Kivity
2009-08-31 21:56 ` Anthony Liguori
2009-08-31 21:56 ` Anthony Liguori
2009-09-01 15:37 ` Xin, Xiaohui
2009-09-01 15:37 ` Xin, Xiaohui
2009-09-01 15:37 ` Xin, Xiaohui
2009-08-31 21:56 ` Anthony Liguori
2009-09-01 5:04 ` Xin, Xiaohui
2009-09-01 5:04 ` Xin, Xiaohui
2009-09-01 5:04 ` Xin, Xiaohui
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