linux.git/include/xen/interface/io/ring.h, branch v4.10 Linux kernel source tree xen/io: use virt_xxx barriers 2016-01-12T18:47:03+00:00 Michael S. Tsirkin mst@redhat.com 2015-12-27T16:02:16+00:00 506b02eb1cf79838b76c6e3e43171cf960f01fc8 include/xen/interface/io/ring.h uses full memory barriers to communicate with the other side. For guests compiled with CONFIG_SMP, smp_wmb and smp_mb would be sufficient, so mb() and wmb() here are only needed if a non-SMP guest runs on an SMP host. Switch to virt_xxx barriers which serve this exact purpose. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> 
include/xen/interface/io/ring.h uses
full memory barriers to communicate with the other side.

For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
would be sufficient, so mb() and wmb() here are only needed if
a non-SMP guest runs on an SMP host.

Switch to virt_xxx barriers which serve this exact purpose.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
xen: Add RING_COPY_REQUEST() 2015-12-18T15:00:17+00:00 David Vrabel david.vrabel@citrix.com 2015-10-30T14:58:08+00:00 454d5d882c7e412b840e3c99010fe81a9862f6fb Using RING_GET_REQUEST() on a shared ring is easy to use incorrectly (i.e., by not considering that the other end may alter the data in the shared ring while it is being inspected). Safe usage of a request generally requires taking a local copy. Provide a RING_COPY_REQUEST() macro to use instead of RING_GET_REQUEST() and an open-coded memcpy(). This takes care of ensuring that the copy is done correctly regardless of any possible compiler optimizations. Use a volatile source to prevent the compiler from reordering or omitting the copy. This is part of XSA155. CC: stable@vger.kernel.org Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 
Using RING_GET_REQUEST() on a shared ring is easy to use incorrectly
(i.e., by not considering that the other end may alter the data in the
shared ring while it is being inspected).  Safe usage of a request
generally requires taking a local copy.

Provide a RING_COPY_REQUEST() macro to use instead of
RING_GET_REQUEST() and an open-coded memcpy().  This takes care of
ensuring that the copy is done correctly regardless of any possible
compiler optimizations.

Use a volatile source to prevent the compiler from reordering or
omitting the copy.

This is part of XSA155.

CC: stable@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/io/ring.h: new macro to detect whether there are too many requests on the ring 2013-06-17T19:17:15+00:00 Jan Beulich jbeulich@suse.com 2013-06-17T19:16:33+00:00 8d9256906a97c24e97e016482b9be06ea2532b05 Backends may need to protect themselves against an insane number of produced requests stored by a frontend, in case they iterate over requests until reaching the req_prod value. There can't be more requests on the ring than the difference between produced requests and produced (but possibly not yet published) responses. This is a more strict alternative to a patch previously posted by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 
Backends may need to protect themselves against an insane number of
produced requests stored by a frontend, in case they iterate over
requests until reaching the req_prod value. There can't be more
requests on the ring than the difference between produced requests
and produced (but possibly not yet published) responses.

This is a more strict alternative to a patch previously posted by
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen: Provide a variant of __RING_SIZE() that is an integer constant expression 2010-12-15T20:34:28+00:00 Jeremy Fitzhardinge jeremy@goop.org 2010-12-08T20:39:12+00:00 667c78afaec0ac500908e191e8f236e9578d7b1f Without this, gcc 4.5 won't compile xen-netfront and xen-blkfront, where this is being used to specify array sizes. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: David Miller <davem@davemloft.net> Cc: Stable Kernel <stable@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Without this, gcc 4.5 won't compile xen-netfront and xen-blkfront, where
this is being used to specify array sizes.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: David Miller <davem@davemloft.net>
Cc: Stable Kernel <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
xen: Add Xen interface header files 2007-07-18T15:47:42+00:00 Jeremy Fitzhardinge jeremy@xensource.com 2007-07-18T01:37:04+00:00 a42089dd358a7673a0a23126589a9029e57c2049 Add Xen interface header files. These are taken fairly directly from the Xen tree, but somewhat rearranged to suit the kernel's conventions. Define macros and inline functions for doing hypercalls into the hypervisor. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org> 
Add Xen interface header files. These are taken fairly directly from
the Xen tree, but somewhat rearranged to suit the kernel's conventions.

Define macros and inline functions for doing hypercalls into the
hypervisor.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>