search for: config_vhost_cross_endian_legaci

On Wed, Jan 13, 2016 at 06:09:41PM +0100, Greg Kurz wrote: > The default use case for vhost is when the host and the vring have the > same endianness (default native endianness). But there are cases where > they differ and vhost should byteswap when accessing the vring: > - the host is big endian and the vring comes from a virtio 1.0 device > which is always little endian > -

On Wed, Jan 13, 2016 at 06:09:41PM +0100, Greg Kurz wrote: > The default use case for vhost is when the host and the vring have the > same endianness (default native endianness). But there are cases where > they differ and vhost should byteswap when accessing the vring: > - the host is big endian and the vring comes from a virtio 1.0 device > which is always little endian > -

On Wed, Feb 10, 2016 at 01:11:34PM +0100, Greg Kurz wrote: > On Wed, 10 Feb 2016 13:21:22 +0200 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > On Wed, Jan 13, 2016 at 06:09:41PM +0100, Greg Kurz wrote: > > > The default use case for vhost is when the host and the vring have the > > > same endianness (default native endianness). But there

On Wed, Feb 10, 2016 at 01:11:34PM +0100, Greg Kurz wrote: > On Wed, 10 Feb 2016 13:21:22 +0200 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > On Wed, Jan 13, 2016 at 06:09:41PM +0100, Greg Kurz wrote: > > > The default use case for vhost is when the host and the vring have the > > > same endianness (default native endianness). But there

This patch brings cross-endian support to vhost when used to implement legacy virtio devices. Since it is a relatively rare situation, the feature availability is controlled by a kernel config option (not set by default). The vq->is_le boolean field is added to cache the endianness to be used for ring accesses. It defaults to native endian, as expected by legacy virtio devices. When the ring

This patch brings cross-endian support to vhost when used to implement legacy virtio devices. Since it is a relatively rare situation, the feature availability is controlled by a kernel config option (not set by default). The vq->is_le boolean field is added to cache the endianness to be used for ring accesses. It defaults to native endian, as expected by legacy virtio devices. When the ring

On Thu, 23 Apr 2015 17:29:42 +0200 Greg Kurz <gkurz at linux.vnet.ibm.com> wrote: > This patch brings cross-endian support to vhost when used to implement > legacy virtio devices. Since it is a relatively rare situation, the > feature availability is controlled by a kernel config option (not set > by default). > > The vq->is_le boolean field is added to cache the

On Thu, 23 Apr 2015 17:29:42 +0200 Greg Kurz <gkurz at linux.vnet.ibm.com> wrote: > This patch brings cross-endian support to vhost when used to implement > legacy virtio devices. Since it is a relatively rare situation, the > feature availability is controlled by a kernel config option (not set > by default). > > The vq->is_le boolean field is added to cache the

Currently, under certain circumstances vhost_init_is_le does just a part of the initialization job, and depends on vhost_reset_is_le being called too. For this reason vhost_vq_init_access used to call vhost_reset_is_le when vq->private_data is NULL. This is not only counter intuitive, but also real a problem because it breaks vhost_net. The bug was introduced to vhost_net with commit

Currently, under certain circumstances vhost_init_is_le does just a part of the initialization job, and depends on vhost_reset_is_le being called too. For this reason vhost_vq_init_access used to call vhost_reset_is_le when vq->private_data is NULL. This is not only counter intuitive, but also real a problem because it breaks vhost_net. The bug was introduced to vhost_net with commit

The default use case for vhost is when the host and the vring have the same endianness (default native endianness). But there are cases where they differ and vhost should byteswap when accessing the vring: - the host is big endian and the vring comes from a virtio 1.0 device which is always little endian - the architecture is bi-endian and the vring comes from a legacy virtio device with a

On 01/26/2017 08:20 PM, Michael S. Tsirkin wrote: > On Thu, Jan 26, 2017 at 06:39:14PM +0100, Halil Pasic wrote: >> >> Hi! >> >> Recently I have been investigating some strange migration problems on >> s390x. >> >> It turned out under certain circumstances vhost_net corrupts avail.idx by >> using wrong endianness. [..] >>

On 01/26/2017 08:20 PM, Michael S. Tsirkin wrote: > On Thu, Jan 26, 2017 at 06:39:14PM +0100, Halil Pasic wrote: >> >> Hi! >> >> Recently I have been investigating some strange migration problems on >> s390x. >> >> It turned out under certain circumstances vhost_net corrupts avail.idx by >> using wrong endianness. [..] >>

Move vhost.h to include/linux to allow vhost driver out-of-tree compilation. Currently, this cannot be done properly because the vhost header file is in driver/vhost. To distribute a new vhost driver before it is included in the kernel tree, we need to package it using kmod, dkms, ..., and to compile it out-of-tree using headers provided by the distribution's kernel development package.

Move vhost.h to include/linux to allow vhost driver out-of-tree compilation. Currently, this cannot be done properly because the vhost header file is in driver/vhost. To distribute a new vhost driver before it is included in the kernel tree, we need to package it using kmod, dkms, ..., and to compile it out-of-tree using headers provided by the distribution's kernel development package.

commit 2751c9882b947292fcfb084c4f604e01724af804 ("vhost: cross-endian support for legacy devices") introduced a minor regression: even with cross-endian disabled, and even on LE host, vhost_is_little_endian is checking is_le flag so there's always a branch. To fix, simply check virtio_legacy_is_little_endian first. Cc: Greg Kurz <gkurz at linux.vnet.ibm.com> Signed-off-by:

commit 2751c9882b947292fcfb084c4f604e01724af804 ("vhost: cross-endian support for legacy devices") introduced a minor regression: even with cross-endian disabled, and even on LE host, vhost_is_little_endian is checking is_le flag so there's always a branch. To fix, simply check virtio_legacy_is_little_endian first. Cc: Greg Kurz <gkurz at linux.vnet.ibm.com> Signed-off-by:

On Wed, 10 Feb 2016 13:21:22 +0200 "Michael S. Tsirkin" <mst at redhat.com> wrote: > On Wed, Jan 13, 2016 at 06:09:41PM +0100, Greg Kurz wrote: > > The default use case for vhost is when the host and the vring have the > > same endianness (default native endianness). But there are cases where > > they differ and vhost should byteswap when accessing the vring:

This series is a new tentative to have cleaner cross-endian code. Patches 1/3 is new: it fixes a side-effect in case vhost_init_used() fails. Patch 2/3 comes from v1: it renames cross-endian helpers Patch 3/3 is new: it simply renames vhost_init_used() as suggested by Michael. --- Greg Kurz (3): vhost: fix error path in vhost_init_used() vhost: rename cross-endian helpers

This series is a new tentative to have cleaner cross-endian code. Patches 1/3 is new: it fixes a side-effect in case vhost_init_used() fails. Patch 2/3 comes from v1: it renames cross-endian helpers Patch 3/3 is new: it simply renames vhost_init_used() as suggested by Michael. --- Greg Kurz (3): vhost: fix error path in vhost_init_used() vhost: rename cross-endian helpers