search for: virtio_f_io_barrier

This patch introduces the support for VIRTIO_F_IO_BARRIER. When this feature is negotiated, driver will use the barriers suitable for hardware devices. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 5 +++++ include/uapi/linux/virtio_config.h | 8 +++++++- 2 files changed, 12 insertions(+), 1 deletion(-)...

This patch introduces the support for VIRTIO_F_IO_BARRIER. When this feature is negotiated, driver will use the barriers suitable for hardware devices. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 5 +++++ include/uapi/linux/virtio_config.h | 8 +++++++- 2 files changed, 12 insertions(+), 1 deletion(-)...

On Thu, May 03, 2018 at 03:30:03PM +0800, Jason Wang wrote: > On 2018?05?03? 10:59, Tiwei Bie wrote: > > This patch introduces the support for VIRTIO_F_IO_BARRIER. > > When this feature is negotiated, driver will use the barriers > > suitable for hardware devices. > > > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > > --- > > drivers/virtio/virtio_ring.c | 5 +++++ > > include/uapi/linux/virtio...

On Thu, May 03, 2018 at 03:30:03PM +0800, Jason Wang wrote: > On 2018?05?03? 10:59, Tiwei Bie wrote: > > This patch introduces the support for VIRTIO_F_IO_BARRIER. > > When this feature is negotiated, driver will use the barriers > > suitable for hardware devices. > > > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > > --- > > drivers/virtio/virtio_ring.c | 5 +++++ > > include/uapi/linux/virtio...

On Thu, May 03, 2018 at 05:09:44PM +0800, Jason Wang wrote: > On 2018?05?03? 16:30, Tiwei Bie wrote: > > On Thu, May 03, 2018 at 03:30:03PM +0800, Jason Wang wrote: > > > On 2018?05?03? 10:59, Tiwei Bie wrote: > > > > This patch introduces the support for VIRTIO_F_IO_BARRIER. > > > > When this feature is negotiated, driver will use the barriers > > > > suitable for hardware devices. > > > > > > > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > > > > --- > > > > drivers/virtio/virtio...

On 2018?05?03? 10:59, Tiwei Bie wrote: > This patch introduces the support for VIRTIO_F_IO_BARRIER. > When this feature is negotiated, driver will use the barriers > suitable for hardware devices. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > --- > drivers/virtio/virtio_ring.c | 5 +++++ > include/uapi/linux/virtio_config.h | 8 +++++++- > 2 file...

On 2018?05?03? 16:30, Tiwei Bie wrote: > On Thu, May 03, 2018 at 03:30:03PM +0800, Jason Wang wrote: >> On 2018?05?03? 10:59, Tiwei Bie wrote: >>> This patch introduces the support for VIRTIO_F_IO_BARRIER. >>> When this feature is negotiated, driver will use the barriers >>> suitable for hardware devices. >>> >>> Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> >>> --- >>> drivers/virtio/virtio_ring.c | 5 +++++ >>> inc...

On Thu, May 03, 2018 at 10:59:55AM +0800, Tiwei Bie wrote: > This patch introduces the support for VIRTIO_F_IO_BARRIER. > When this feature is negotiated, driver will use the barriers > suitable for hardware devices. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> Thanks! > --- > drivers/virtio/virtio_ring.c | 5 +++++ > include/uapi/linux/virtio_config.h | 8 +++++++- >...

This patch introduces the support for VIRTIO_F_IO_BARRIER. When this feature is negotiated, driver will use the barriers suitable for hardware devices. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- This patch depends on below proposal for virtio-spec: https://lists.oasis-open.org/archives/virtio-dev/201805/msg00019.html This patch also dep...

On Thu, May 03, 2018 at 10:06:52AM +0100, Stefan Hajnoczi wrote: > On Thu, May 03, 2018 at 10:59:55AM +0800, Tiwei Bie wrote: > > This patch introduces the support for VIRTIO_F_IO_BARRIER. > > When this feature is negotiated, driver will use the barriers > > suitable for hardware devices. > > > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > > I should have thought of this earlier, but why is a new feature bit > necessary? If a hardwar...

On Thu, May 03, 2018 at 10:59:55AM +0800, Tiwei Bie wrote: > This patch introduces the support for VIRTIO_F_IO_BARRIER. > When this feature is negotiated, driver will use the barriers > suitable for hardware devices. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> I should have thought of this earlier, but why is a new feature bit necessary? If a hardware virtio device is in use, then the...

On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote: > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h > index 308e2096291f..9fb519a9df28 100644 > --- a/include/uapi/linux/virtio_config.h > +++ b/include/uapi/linux/virtio_config.h > @@ -49,7 +49,7 @@ > * transport being used (eg. virtio_ring), the rest are per-device feature > *

On Thu, May 10, 2018 at 06:39:41PM +0800, Tiwei Bie wrote: > On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote: > > On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote: > > > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h > > > index 308e2096291f..9fb519a9df28 100644 > > > ---

...self into a secure VM and thus will require bounce buffering for IOs (including virtio). So unless we have another hook for the arch code to set VIRTIO_F_PLATFORM_DMA on selected (or all) virtio devices from the guest itself, I don't see that as a way to deal with it. > The other issue is VIRTIO_F_IO_BARRIER > which is very vaguely defined, and which needs a better definition. > And last but not least we'll need some text explaining the challenges > of hardware devices - I think VIRTIO_F_PLATFORM_DMA + VIRTIO_F_IO_BARRIER > is what would basically cover them, but a good description incl...

...self into a secure VM and thus will require bounce buffering for IOs (including virtio). So unless we have another hook for the arch code to set VIRTIO_F_PLATFORM_DMA on selected (or all) virtio devices from the guest itself, I don't see that as a way to deal with it. > The other issue is VIRTIO_F_IO_BARRIER > which is very vaguely defined, and which needs a better definition. > And last but not least we'll need some text explaining the challenges > of hardware devices - I think VIRTIO_F_PLATFORM_DMA + VIRTIO_F_IO_BARRIER > is what would basically cover them, but a good description incl...

On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote: > On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote: > > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h > > index 308e2096291f..9fb519a9df28 100644 > > --- a/include/uapi/linux/virtio_config.h > > +++ b/include/uapi/linux/virtio_config.h > > @@ -49,7 +49,7

On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote: > On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote: > > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h > > index 308e2096291f..9fb519a9df28 100644 > > --- a/include/uapi/linux/virtio_config.h > > +++ b/include/uapi/linux/virtio_config.h > > @@ -49,7 +49,7

On Tue, Jul 31, 2018 at 03:36:22PM -0500, Benjamin Herrenschmidt wrote: > On Tue, 2018-07-31 at 10:30 -0700, Christoph Hellwig wrote: > > > However the question people raise is that DMA API is already full of > > > arch-specific tricks the likes of which are outlined in your post linked > > > above. How is this one much worse? > > > > None of these warts

On Tue, Jul 31, 2018 at 03:36:22PM -0500, Benjamin Herrenschmidt wrote: > On Tue, 2018-07-31 at 10:30 -0700, Christoph Hellwig wrote: > > > However the question people raise is that DMA API is already full of > > > arch-specific tricks the likes of which are outlined in your post linked > > > above. How is this one much worse? > > > > None of these warts

...for IOs (including virtio). > > > > So unless we have another hook for the arch code to set > > VIRTIO_F_PLATFORM_DMA on selected (or all) virtio devices from the > > guest itself, I don't see that as a way to deal with it. > > > > > The other issue is VIRTIO_F_IO_BARRIER > > > which is very vaguely defined, and which needs a better definition. > > > And last but not least we'll need some text explaining the challenges > > > of hardware devices - I think VIRTIO_F_PLATFORM_DMA + VIRTIO_F_IO_BARRIER > > > is what would basically...