On 08/26/2015 10:51 PM, Greg Kurz wrote: > On Wed, 26 Aug 2015 15:21:59 +0100 > Peter Maydell <peter.mayd...@linaro.org> wrote: > >> On 26 August 2015 at 11:04, Jason Wang <jasow...@redhat.com> wrote: >>> Wildcard mmio eventfd use zero size, but it will lead abort() since it >>> was illegal in adjust_endianness(). Fix this by allowing zero size. >>> >>> Cc: Greg Kurz <gk...@linux.vnet.ibm.com> >>> Cc: Paolo Bonzini <pbonz...@redhat.com> >>> Signed-off-by: Jason Wang <jasow...@redhat.com> >> This seems to me like a bug in the caller. Why would anything >> try to call into the memory subsystem to do a zero-size >> transaction? >> >> thanks >> -- PMM >> > Here's the patch which needs zero-size eventfd: > > http://patchwork.ozlabs.org/patch/509428/ > > Cheers. > > -- > Greg >
Yes, this is because we want to use wildcard mmio eventfd (which requires size to be zero) to speed up virtio 1.0 mmio.
