On Fri, 2018-06-15 at 02:16 -0700, Christoph Hellwig wrote:
> On Wed, Jun 13, 2018 at 11:11:01PM +1000, Benjamin Herrenschmidt wrote:
> > Actually ... the stuff in lib/dma-direct.c seems to be just it, no ?
> >
> > There's no cache flushing and there's no architecture hooks that I can
> > see othe
On Wed, Jun 13, 2018 at 11:11:01PM +1000, Benjamin Herrenschmidt wrote:
> Actually ... the stuff in lib/dma-direct.c seems to be just it, no ?
>
> There's no cache flushing and there's no architecture hooks that I can
> see other than the AMD security stuff which is probably fine.
>
> Or am I mis
On Mon, Jun 11, 2018 at 01:34:50PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-06-11 at 06:28 +0300, Michael S. Tsirkin wrote:
> >
> > > However if the administrator
> > > ignores/forgets/deliberatey-decides/is-constrained to NOT enable the
> > > flag, virtio will not be able to pass contr
On Mon, Jun 11, 2018 at 01:29:18PM +1000, Benjamin Herrenschmidt wrote:
> On Sun, 2018-06-10 at 19:39 -0700, Ram Pai wrote:
> >
> > However if the administrator
> > ignores/forgets/deliberatey-decides/is-constrained to NOT enable the
> > flag, virtio will not be able to pass control to the DMA ops
On Wed, Jun 13, 2018 at 12:41:41AM -0700, Christoph Hellwig wrote:
> On Mon, Jun 11, 2018 at 01:29:18PM +1000, Benjamin Herrenschmidt wrote:
> > At the risk of repeating myself, let's just do the first pass which is
> > to switch virtio over to always using the DMA API in the actual data
> > flow c
On Thu, Jun 07, 2018 at 11:36:55PM -0700, Christoph Hellwig wrote:
> > This seems to be what was being asked for in this thread,
> > with comments claiming IOMMU flag adds too much overhead.
>
> Right now it means implementing a virtual iommu, which I agree is
> way too much overhead.
Well not re
On Wed, 2018-06-13 at 22:25 +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2018-06-13 at 00:41 -0700, Christoph Hellwig wrote:
> > On Mon, Jun 11, 2018 at 01:29:18PM +1000, Benjamin Herrenschmidt wrote:
> > > At the risk of repeating myself, let's just do the first pass which is
> > > to switch vir
On Wed, 2018-06-13 at 00:41 -0700, Christoph Hellwig wrote:
> On Mon, Jun 11, 2018 at 01:29:18PM +1000, Benjamin Herrenschmidt wrote:
> > At the risk of repeating myself, let's just do the first pass which is
> > to switch virtio over to always using the DMA API in the actual data
> > flow code, wi
On Mon, Jun 11, 2018 at 01:29:18PM +1000, Benjamin Herrenschmidt wrote:
> At the risk of repeating myself, let's just do the first pass which is
> to switch virtio over to always using the DMA API in the actual data
> flow code, with a hook at initialization time that replaces the DMA ops
> with so
On Mon, 2018-06-11 at 06:28 +0300, Michael S. Tsirkin wrote:
>
> > However if the administrator
> > ignores/forgets/deliberatey-decides/is-constrained to NOT enable the
> > flag, virtio will not be able to pass control to the DMA ops associated
> > with the virtio devices. Which means, we have no
On Sun, 2018-06-10 at 19:39 -0700, Ram Pai wrote:
>
> However if the administrator
> ignores/forgets/deliberatey-decides/is-constrained to NOT enable the
> flag, virtio will not be able to pass control to the DMA ops associated
> with the virtio devices. Which means, we have no opportunity to shar
On Sun, Jun 10, 2018 at 07:39:09PM -0700, Ram Pai wrote:
> On Thu, Jun 07, 2018 at 07:28:35PM +0300, Michael S. Tsirkin wrote:
> > On Wed, Jun 06, 2018 at 10:23:06PM -0700, Christoph Hellwig wrote:
> > > On Thu, May 31, 2018 at 08:43:58PM +0300, Michael S. Tsirkin wrote:
> > > > Pls work on a long
On Thu, Jun 07, 2018 at 07:28:35PM +0300, Michael S. Tsirkin wrote:
> On Wed, Jun 06, 2018 at 10:23:06PM -0700, Christoph Hellwig wrote:
> > On Thu, May 31, 2018 at 08:43:58PM +0300, Michael S. Tsirkin wrote:
> > > Pls work on a long term solution. Short term needs can be served by
> > > enabling t
On Thu, Jun 07, 2018 at 07:28:35PM +0300, Michael S. Tsirkin wrote:
> Let me restate it: DMA API has support for a wide range of hardware, and
> hardware based virtio implementations likely won't benefit from all of
> it.
That is completely wrong. All aspects of the DMA API are about the
system t
On Wed, Jun 06, 2018 at 10:23:06PM -0700, Christoph Hellwig wrote:
> On Thu, May 31, 2018 at 08:43:58PM +0300, Michael S. Tsirkin wrote:
> > Pls work on a long term solution. Short term needs can be served by
> > enabling the iommu platform in qemu.
>
> So, I spent some time looking at converting
On Thu, May 31, 2018 at 08:43:58PM +0300, Michael S. Tsirkin wrote:
> Pls work on a long term solution. Short term needs can be served by
> enabling the iommu platform in qemu.
So, I spent some time looking at converting virtio to dma ops overrides,
and the current virtio spec, and the sad through
On Tue, Jun 05, 2018 at 09:26:56AM +1000, Benjamin Herrenschmidt wrote:
> Sorry Michael, that doesn't click. Yes of course virtio is implemented
> in qemu, but the problem we are trying to solve is *not* a qemu problem
> (the fact that the Linux drivers bypass the DMA API is wrong, needs
> fixing,
On Mon, Jun 04, 2018 at 07:48:54PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-06-04 at 18:57 +1000, David Gibson wrote:
> >
> > > - First qemu doesn't know that the guest will switch to "secure mode"
> > > in advance. There is no difference between a normal and a secure
> > > partition un
On Tue, Jun 05, 2018 at 09:26:56AM +1000, Benjamin Herrenschmidt wrote:
> I would like to keep however the ability to bypass the iommu for
> performance reasons
So that's easy, clear the IOMMU flag and this means "bypass the IOMMU".
--
MST
On Mon, 2018-06-04 at 19:21 +0300, Michael S. Tsirkin wrote:
>
> > > > - First qemu doesn't know that the guest will switch to "secure mode"
> > > > in advance. There is no difference between a normal and a secure
> > > > partition until the partition does the magic UV call to "enter secure
> > >
On Mon, Jun 04, 2018 at 11:14:36PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-06-04 at 05:55 -0700, Christoph Hellwig wrote:
> > On Mon, Jun 04, 2018 at 03:43:09PM +0300, Michael S. Tsirkin wrote:
> > > Another is that given the basic functionality is in there, optimizations
> > > can poss
On Mon, Jun 04, 2018 at 11:11:52PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-06-04 at 15:43 +0300, Michael S. Tsirkin wrote:
> > On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> > > On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
> > >
> > > > I re-r
On Mon, 2018-06-04 at 05:55 -0700, Christoph Hellwig wrote:
> On Mon, Jun 04, 2018 at 03:43:09PM +0300, Michael S. Tsirkin wrote:
> > Another is that given the basic functionality is in there, optimizations
> > can possibly wait until per-device quirks in DMA API are supported.
>
> We have had per
On Mon, Jun 04, 2018 at 03:43:09PM +0300, Michael S. Tsirkin wrote:
> Another is that given the basic functionality is in there, optimizations
> can possibly wait until per-device quirks in DMA API are supported.
We have had per-device dma_ops for quite a while.
On Mon, 2018-06-04 at 15:43 +0300, Michael S. Tsirkin wrote:
> On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> > On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
> >
> > > I re-read that discussion and I'm still unclear on the
> > > original question, since I
On Mon, Jun 04, 2018 at 07:48:54PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-06-04 at 18:57 +1000, David Gibson wrote:
> >
> > > - First qemu doesn't know that the guest will switch to "secure mode"
> > > in advance. There is no difference between a normal and a secure
> > > partition un
On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
>
> > I re-read that discussion and I'm still unclear on the
> > original question, since I got several apparently
> > conflicting answers.
> >
> > I asked:
> >
On Mon, 2018-06-04 at 18:57 +1000, David Gibson wrote:
>
> > - First qemu doesn't know that the guest will switch to "secure mode"
> > in advance. There is no difference between a normal and a secure
> > partition until the partition does the magic UV call to "enter secure
> > mode" and qemu doesn
On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
>
> > I re-read that discussion and I'm still unclear on the
> > original question, since I got several apparently
> > conflicting answers.
> >
> > I asked:
> >
On Thu, May 31, 2018 at 09:09:24AM +0530, Anshuman Khandual wrote:
> On 05/24/2018 12:51 PM, Ram Pai wrote:
> > On Wed, May 23, 2018 at 09:50:02PM +0300, Michael S. Tsirkin wrote:
> >> subj: s/virito/virtio/
> >>
> > ..snip..
> >>> machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init)
On 05/24/2018 12:51 PM, Ram Pai wrote:
> On Wed, May 23, 2018 at 09:50:02PM +0300, Michael S. Tsirkin wrote:
>> subj: s/virito/virtio/
>>
> ..snip..
>>> machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);
>>> +
>>> +bool platform_forces_virtio_dma(struct virtio_device *vdev)
>>> +{
On Tue, 2018-05-29 at 07:03 -0700, Christoph Hellwig wrote:
> On Tue, May 29, 2018 at 09:56:24AM +1000, Benjamin Herrenschmidt wrote:
> > I don't think forcing the addition of an emulated iommu in the middle
> > just to work around the fact that virtio "cheats" and doesn't use the
> > dma API unles
On Tue, May 29, 2018 at 09:56:24AM +1000, Benjamin Herrenschmidt wrote:
> I don't think forcing the addition of an emulated iommu in the middle
> just to work around the fact that virtio "cheats" and doesn't use the
> dma API unless there is one, is the right "fix".
Agreed.
> The right long term
On Tue, 2018-05-29 at 09:48 +1000, Benjamin Herrenschmidt wrote:
> > Well it's not supposed to be much slower for the static case.
> >
> > vhost has a cache so should be fine.
> >
> > A while ago Paolo implemented a translation cache which should be
> > perfect for this case - most of the code go
On Fri, 2018-05-25 at 20:45 +0300, Michael S. Tsirkin wrote:
> On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> > On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
> >
> > > I re-read that discussion and I'm still unclear on the
> > > original question, since I
On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
>
> > I re-read that discussion and I'm still unclear on the
> > original question, since I got several apparently
> > conflicting answers.
> >
> > I asked:
> >
On Thu, May 24, 2018 at 08:27:04AM +1000, Benjamin Herrenschmidt wrote:
> - First qemu doesn't know that the guest will switch to "secure mode"
> in advance. There is no difference between a normal and a secure
> partition until the partition does the magic UV call to "enter secure
> mode" and qemu
On Wed, May 23, 2018 at 09:50:02PM +0300, Michael S. Tsirkin wrote:
> subj: s/virito/virtio/
>
..snip..
> > machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);
> > +
> > +bool platform_forces_virtio_dma(struct virtio_device *vdev)
> > +{
> > + /*
> > +* On protected guest pl
On Wed, 2018-05-23 at 21:50 +0300, Michael S. Tsirkin wrote:
> I re-read that discussion and I'm still unclear on the
> original question, since I got several apparently
> conflicting answers.
>
> I asked:
>
> Why isn't setting VIRTIO_F_IOMMU_PLATFORM on the
> hypervisor side suffici
subj: s/virito/virtio/
On Tue, May 22, 2018 at 12:03:17PM +0530, Anshuman Khandual wrote:
> This adds a hook which a platform can define in order to allow it to
> force the use of the DMA API for all virtio devices even if they don't
> have the VIRTIO_F_IOMMU_PLATFORM flag set. We want to use thi
This adds a hook which a platform can define in order to allow it to
force the use of the DMA API for all virtio devices even if they don't
have the VIRTIO_F_IOMMU_PLATFORM flag set. We want to use this to do
bounce-buffering of data on the new secure pSeries platform, currently
under development,
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