> > this to set the VIRTIO_F_IOMMU_PLATFORM flag. But for example
> > QEMU has the use of iommu_platform attribute disabled for virtio-gpu
> > device. So would also like to move towards not having to specify
> > the VIRTIO_F_IOMMU_PLATFORM flag.
>
> Specifying VIRTIO_F_IOMMU_PLATFORM is the right
On Thu, Sep 06, 2018 at 07:09:09PM -0500, Jiandi An wrote:
> For virtio device we have to pass in iommu_platform=true flag for
> this to set the VIRTIO_F_IOMMU_PLATFORM flag. But for example
> QEMU has the use of iommu_platform attribute disabled for virtio-gpu
> device. So would also like to move
On Thu, Aug 09, 2018 at 08:13:32AM +1000, Benjamin Herrenschmidt wrote:
> > > - if (xen_domain())
> > > + if (xen_domain() || pseries_secure_vm())
> > > return true;
> >
> > I don't think it's pseries specific actually. E.g. I suspect AMD SEV
> > might benefit from the same kind of hack.
On Thu, 2018-08-09 at 08:13 +1000, Benjamin Herrenschmidt wrote:
> > For completeness, virtio could also have its own bounce buffer
> > outside of DMA API one. I don't see lots of benefits to this
> > though.
>
> Not fan of that either...
To elaborate a bit ...
For our secure VMs, we will need b
On Wed, 2018-08-08 at 23:31 +0300, Michael S. Tsirkin wrote:
> On Wed, Aug 08, 2018 at 11:18:13PM +1000, Benjamin Herrenschmidt wrote:
> > Sure, but all of this is just the configuration of the iommu. But I
> > think we agree here, and your point remains valid, indeed my proposed
> > hack:
> >
> >
On Wed, Aug 08, 2018 at 11:18:13PM +1000, Benjamin Herrenschmidt wrote:
> Sure, but all of this is just the configuration of the iommu. But I
> think we agree here, and your point remains valid, indeed my proposed
> hack:
>
> > if ((flags & VIRTIO_F_IOMMU_PLATFORM) || arch_virtio_wants_dma_o
On Wed, 2018-08-08 at 05:30 -0700, Christoph Hellwig wrote:
> On Wed, Aug 08, 2018 at 08:07:49PM +1000, Benjamin Herrenschmidt wrote:
> > Qemu virtio bypasses that iommu when the VIRTIO_F_IOMMU_PLATFORM flag
> > is not set (default) but there's nothing in the device-tree to tell the
> > guest about
On Wed, Aug 08, 2018 at 08:07:49PM +1000, Benjamin Herrenschmidt wrote:
> Qemu virtio bypasses that iommu when the VIRTIO_F_IOMMU_PLATFORM flag
> is not set (default) but there's nothing in the device-tree to tell the
> guest about this since it's a violation of our pseries architecture, so
> we ju
On Tue, 2018-08-07 at 23:31 -0700, Christoph Hellwig wrote:
>
> You don't need to set them the time you go secure. You just need to
> set the flag from the beginning on any VM you might want to go secure.
> Or for simplicity just any VM - if the DT/ACPI tables exposed by
> qemu are good enough th
On Wed, Aug 08, 2018 at 06:32:45AM +1000, Benjamin Herrenschmidt wrote:
> As for the flag itself, while we could set it from qemu when we get
> notified that the guest is going secure, both Michael and I think it's
> rather gross, it requires qemu to go iterate all virtio devices and
> "poke" somet
On Tue, 2018-08-07 at 06:55 -0700, Christoph Hellwig wrote:
> On Tue, Aug 07, 2018 at 04:42:44PM +1000, Benjamin Herrenschmidt wrote:
> > Note that I can make it so that the same DMA ops (basically standard
> > swiotlb ops without arch hacks) work for both "direct virtio" and
> > "normal PCI" devic
On Tue, Aug 07, 2018 at 04:42:44PM +1000, Benjamin Herrenschmidt wrote:
> Note that I can make it so that the same DMA ops (basically standard
> swiotlb ops without arch hacks) work for both "direct virtio" and
> "normal PCI" devices.
>
> The trick is simply in the arch to setup the iommu to map t
On Mon, 2018-08-06 at 23:27 -0700, Christoph Hellwig wrote:
> On Tue, Aug 07, 2018 at 08:13:56AM +1000, Benjamin Herrenschmidt wrote:
> > It would be indeed ideal if all we had to do was setup some kind of
> > bus_dma_mask on all PCI devices and have virtio automagically insert
> > swiotlb when nec
On Mon, 2018-08-06 at 23:21 -0700, Christoph Hellwig wrote:
> On Tue, Aug 07, 2018 at 05:52:12AM +1000, Benjamin Herrenschmidt wrote:
> > > It is your job to write a coherent interface specification that does
> > > not depend on the used components. The hypervisor might be PAPR,
> > > Linux + qemu
On Tue, Aug 07, 2018 at 02:45:25AM +0300, Michael S. Tsirkin wrote:
> > > I think that's where Christoph might have specific ideas about it.
> >
> > OK well, assuming Christoph can solve the direct case in a way that
> > also work for the virtio !iommu case, we still want some bit of logic
> > som
On Tue, Aug 07, 2018 at 08:13:56AM +1000, Benjamin Herrenschmidt wrote:
> It would be indeed ideal if all we had to do was setup some kind of
> bus_dma_mask on all PCI devices and have virtio automagically insert
> swiotlb when necessary.
For 4.20 I plan to remove the swiotlb ops and instead do th
On Tue, Aug 07, 2018 at 05:52:12AM +1000, Benjamin Herrenschmidt wrote:
> > It is your job to write a coherent interface specification that does
> > not depend on the used components. The hypervisor might be PAPR,
> > Linux + qemu, VMware, Hyperv or something so secret that you'd have
> > to shoot
On Tue, Aug 07, 2018 at 12:46:34AM +0300, Michael S. Tsirkin wrote:
> Well we have the RFC for that - the switch to using DMA ops unconditionally
> isn't
> problematic itself IMHO, for now that RFC is blocked
> by its perfromance overhead for now but Christoph says
> he's trying to remove that for
On Tue, Aug 07, 2018 at 07:26:35AM +1000, Benjamin Herrenschmidt wrote:
> > I think Christoph merely objects to the specific implementation. If
> > instead you do something like tweak dev->bus_dma_mask for the virtio
> > device I think he won't object.
>
> Well, we don't have "bus_dma_mask" yet .
On Mon, Aug 06, 2018 at 11:35:39PM +0300, Michael S. Tsirkin wrote:
> > As I said replying to Christoph, we are "leaking" into the interface
> > something here that is really what's the VM is doing to itself, which
> > is to stash its memory away in an inaccessible place.
> >
> > Cheers,
> > Ben.
On Tue, 2018-08-07 at 02:45 +0300, Michael S. Tsirkin wrote:
> > OK well, assuming Christoph can solve the direct case in a way that
> > also work for the virtio !iommu case, we still want some bit of logic
> > somewhere that will "switch" to swiotlb based ops if the DMA mask is
> > limited.
> >
>
On Tue, Aug 07, 2018 at 08:13:56AM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2018-08-07 at 00:46 +0300, Michael S. Tsirkin wrote:
> > On Tue, Aug 07, 2018 at 07:26:35AM +1000, Benjamin Herrenschmidt wrote:
> > > On Mon, 2018-08-06 at 23:35 +0300, Michael S. Tsirkin wrote:
> > > > > As I said r
On Mon, 2018-08-06 at 23:35 +0300, Michael S. Tsirkin wrote:
> On Tue, Aug 07, 2018 at 05:56:59AM +1000, Benjamin Herrenschmidt wrote:
> > On Mon, 2018-08-06 at 16:46 +0300, Michael S. Tsirkin wrote:
> > >
> > > > Right, we'll need some quirk to disable balloons in the guest I
> > > > suppose.
>
On Tue, 2018-08-07 at 08:13 +1000, Benjamin Herrenschmidt wrote:
>
> OK well, assuming Christoph can solve the direct case in a way that
> also work for the virtio !iommu case, we still want some bit of logic
> somewhere that will "switch" to swiotlb based ops if the DMA mask is
> limited.
>
> Yo
On Tue, 2018-08-07 at 00:46 +0300, Michael S. Tsirkin wrote:
> On Tue, Aug 07, 2018 at 07:26:35AM +1000, Benjamin Herrenschmidt wrote:
> > On Mon, 2018-08-06 at 23:35 +0300, Michael S. Tsirkin wrote:
> > > > As I said replying to Christoph, we are "leaking" into the interface
> > > > something here
On Tue, Aug 07, 2018 at 07:26:35AM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-08-06 at 23:35 +0300, Michael S. Tsirkin wrote:
> > > As I said replying to Christoph, we are "leaking" into the interface
> > > something here that is really what's the VM is doing to itself, which
> > > is to s
On Mon, 2018-08-06 at 23:35 +0300, Michael S. Tsirkin wrote:
> > As I said replying to Christoph, we are "leaking" into the interface
> > something here that is really what's the VM is doing to itself, which
> > is to stash its memory away in an inaccessible place.
> >
> > Cheers,
> > Ben.
>
> I
On Tue, Aug 07, 2018 at 05:56:59AM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2018-08-06 at 16:46 +0300, Michael S. Tsirkin wrote:
> >
> > > Right, we'll need some quirk to disable balloons in the guest I
> > > suppose.
> > >
> > > Passing something from libvirt is cumbersome because the end
On Mon, 2018-08-06 at 16:46 +0300, Michael S. Tsirkin wrote:
>
> > Right, we'll need some quirk to disable balloons in the guest I
> > suppose.
> >
> > Passing something from libvirt is cumbersome because the end user may
> > not even need to know about secure VMs. There are use cases where the
On Mon, 2018-08-06 at 02:42 -0700, Christoph Hellwig wrote:
> On Mon, Aug 06, 2018 at 07:16:47AM +1000, Benjamin Herrenschmidt wrote:
> > Who would set this bit ? qemu ? Under what circumstances ?
>
> I don't really care who sets what. The implementation might not even
> involved qemu.
>
> It is
On Mon, Aug 06, 2018 at 07:13:32PM +0300, Michael S. Tsirkin wrote:
> Oh that makes sense then. Could you post a pointer pls so
> this patchset is rebased on top (there are things to
> change about 4/4 but 1-3 could go in if they don't add
> overhead)?
The dma mapping direct calls will need a majo
On Mon, Aug 06, 2018 at 09:10:40AM -0700, Christoph Hellwig wrote:
> On Mon, Aug 06, 2018 at 07:06:05PM +0300, Michael S. Tsirkin wrote:
> > > I've done something very similar in the thread I posted a few years
> > > ago.
> >
> > Right so that was before spectre where a virtual call was cheaper :(
On Mon, Aug 06, 2018 at 07:06:05PM +0300, Michael S. Tsirkin wrote:
> > I've done something very similar in the thread I posted a few years
> > ago.
>
> Right so that was before spectre where a virtual call was cheaper :(
Sorry, I meant days, not years. The whole point of the thread was the
slow
On Mon, Aug 06, 2018 at 08:24:06AM -0700, Christoph Hellwig wrote:
> On Mon, Aug 06, 2018 at 04:36:43PM +0300, Michael S. Tsirkin wrote:
> > On Mon, Aug 06, 2018 at 02:32:28PM +0530, Anshuman Khandual wrote:
> > > On 08/05/2018 05:54 AM, Michael S. Tsirkin wrote:
> > > > On Fri, Aug 03, 2018 at 08:
On Mon, Aug 06, 2018 at 04:36:43PM +0300, Michael S. Tsirkin wrote:
> On Mon, Aug 06, 2018 at 02:32:28PM +0530, Anshuman Khandual wrote:
> > On 08/05/2018 05:54 AM, Michael S. Tsirkin wrote:
> > > On Fri, Aug 03, 2018 at 08:21:26PM -0500, Benjamin Herrenschmidt wrote:
> > >> On Fri, 2018-08-03 at 2
Hi Michael,
On Sun, Aug 05, 2018 at 03:27:42AM +0300, Michael S. Tsirkin wrote:
> On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> > 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:
> > > > > How
On Sun, Aug 05, 2018 at 02:52:54PM +1000, Benjamin Herrenschmidt wrote:
> On Sun, 2018-08-05 at 03:22 +0300, Michael S. Tsirkin wrote:
> > I see the allure of this, but I think down the road you will
> > discover passing a flag in libvirt XML saying
> > "please use a secure mode" or whatever is a g
On Mon, Aug 06, 2018 at 02:32:28PM +0530, Anshuman Khandual wrote:
> On 08/05/2018 05:54 AM, Michael S. Tsirkin wrote:
> > On Fri, Aug 03, 2018 at 08:21:26PM -0500, Benjamin Herrenschmidt wrote:
> >> On Fri, 2018-08-03 at 22:08 +0300, Michael S. Tsirkin wrote:
> >> Please go through these patch
On Mon, Aug 06, 2018 at 07:16:47AM +1000, Benjamin Herrenschmidt wrote:
> Who would set this bit ? qemu ? Under what circumstances ?
I don't really care who sets what. The implementation might not even
involved qemu.
It is your job to write a coherent interface specification that does
not depend
On 08/05/2018 05:54 AM, Michael S. Tsirkin wrote:
> On Fri, Aug 03, 2018 at 08:21:26PM -0500, Benjamin Herrenschmidt wrote:
>> On Fri, 2018-08-03 at 22:08 +0300, Michael S. Tsirkin wrote:
>> Please go through these patches and review whether this approach broadly
>> makes sense. I will appr
On Mon, 2018-08-06 at 07:16 +1000, Benjamin Herrenschmidt wrote:
> I'm trying to understand because the limitation is not a device side
> limitation, it's not a qemu limitation, it's actually more of a VM
> limitation. It has most of its memory pages made inaccessible for
> security reasons. The pl
On Sun, 2018-08-05 at 00:29 -0700, Christoph Hellwig wrote:
> On Sun, Aug 05, 2018 at 11:10:15AM +1000, Benjamin Herrenschmidt wrote:
> > - One you have rejected, which is to have a way for "no-iommu" virtio
> > (which still doesn't use an iommu on the qemu side and doesn't need
> > to), to be for
On Sun, Aug 05, 2018 at 11:10:15AM +1000, Benjamin Herrenschmidt wrote:
> - One you have rejected, which is to have a way for "no-iommu" virtio
> (which still doesn't use an iommu on the qemu side and doesn't need
> to), to be forced to use some custom DMA ops on the VM side.
>
> - One, which sa
On Sun, Aug 05, 2018 at 03:09:55AM +0300, Michael S. Tsirkin wrote:
> So in this case however I'm not sure what exactly do we want to add. It
> seems that from point of view of the device, there is nothing special -
> it just gets a PA and writes there. It also seems that guest does not
> need to
On Sun, 2018-08-05 at 03:22 +0300, Michael S. Tsirkin wrote:
> I see the allure of this, but I think down the road you will
> discover passing a flag in libvirt XML saying
> "please use a secure mode" or whatever is a good idea.
>
> Even thought it is probably not required to address this
> specif
On Sat, 2018-08-04 at 01:21 -0700, Christoph Hellwig wrote:
> No matter if you like it or not (I don't!) virtio is defined to bypass
> dma translations, it is very clearly stated in the spec. It has some
> ill-defined bits to bypass it, so if you want the dma mapping API
> to be used you'll have t
On Sun, 2018-08-05 at 03:09 +0300, Michael S. Tsirkin wrote:
> It seems that the fact that within guest it's implemented using a bounce
> buffer and that it's easiest to do by switching virtio to use the DMA API
> isn't something virtio spec concerns itself with.
Right, this is my reasoning as wel
On Sat, 2018-08-04 at 01:15 -0700, Christoph Hellwig wrote:
> b) a way to document in a virtio-related spec how the bus handles
> dma for Ben's totally fucked up hypervisor. Without that there
> is not way we'll get interoperable implementations.
Christoph, this isn't a totally fucked
On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> 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 t
On Fri, Aug 03, 2018 at 08:22:11PM -0500, Benjamin Herrenschmidt wrote:
> (Appologies if you got this twice, my mailer had a brain fart and I don't
> know if the first one got through & am about to disappear in a plane for 17h)
I got like 3 of these. I hope that's true for everyone as I replied to
On Fri, Aug 03, 2018 at 08:21:26PM -0500, Benjamin Herrenschmidt wrote:
> On Fri, 2018-08-03 at 22:08 +0300, Michael S. Tsirkin wrote:
> > > > > Please go through these patches and review whether this approach
> > > > > broadly
> > > > > makes sense. I will appreciate suggestions, inputs, comments
On Fri, Aug 03, 2018 at 08:16:21PM -0500, Benjamin Herrenschmidt wrote:
> On Fri, 2018-08-03 at 22:07 +0300, Michael S. Tsirkin wrote:
> > On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > > 2- Make vi
On Sat, Aug 04, 2018 at 01:15:00AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 03, 2018 at 10:17:32PM +0300, Michael S. Tsirkin wrote:
> > It seems reasonable to teach a platform to override dma-range
> > for a specific device e.g. in case it knows about bugs in ACPI.
>
> A platform will be able
On Fri, Aug 03, 2018 at 01:58:46PM -0500, Benjamin Herrenschmidt wrote:
> You are saying something along the lines of "I don't like an
> instruction in your ISA, let's not support your entire CPU architecture
> in Linux".
No. I'm saying if you can't describe your architecture in the virtio
spec d
On Fri, Aug 03, 2018 at 10:17:32PM +0300, Michael S. Tsirkin wrote:
> It seems reasonable to teach a platform to override dma-range
> for a specific device e.g. in case it knows about bugs in ACPI.
A platform will be able override dma-range using the dev->bus_dma_mask
field starting in 4.19. But
On Fri, 2018-08-03 at 22:08 +0300, Michael S. Tsirkin wrote:
> > > > Please go through these patches and review whether this approach broadly
> > > > makes sense. I will appreciate suggestions, inputs, comments regarding
> > > > the patches or the approach in general. Thank you.
> > >
> > > Jason
On Fri, 2018-08-03 at 22:07 +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > 2- Make virtio use the DMA API with our custom platform-provided
> > > > swiotlb callbacks
On Fri, 2018-08-03 at 22:07 +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > 2- Make virtio use the DMA API with our custom platform-provided
> > > > swiotlb callbacks
On Fri, 2018-08-03 at 22:07 +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > 2- Make virtio use the DMA API with our custom platform-provided
> > > > swiotlb callbacks
On Fri, 2018-08-03 at 22:07 +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > 2- Make virtio use the DMA API with our custom platform-provided
> > > > swiotlb callbacks
On Fri, Aug 03, 2018 at 12:05:07AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 02, 2018 at 04:13:09PM -0500, Benjamin Herrenschmidt wrote:
> > So let's differenciate the two problems of having an IOMMU (real or
> > emulated) which indeeds adds overhead etc... and using the DMA API.
> >
> > At th
On Fri, Aug 03, 2018 at 10:41:41AM +0800, Jason Wang wrote:
>
>
> On 2018年08月03日 04:55, Michael S. Tsirkin wrote:
> > On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
> > > This patch series is the follow up on the discussions we had before about
> > > the RFC titled [RFC,V2] vi
On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > 2- Make virtio use the DMA API with our custom platform-provided
> > > swiotlb callbacks when needed, that is when not using IOMMU *and*
> > > running on a s
On Fri, 2018-08-03 at 09:02 -0700, Christoph Hellwig wrote:
> On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> > On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > > 2- Make virtio use the DMA API with our custom platform-provided
> > > > swiotlb callbacks
On Fri, Aug 03, 2018 at 10:58:36AM -0500, Benjamin Herrenschmidt wrote:
> On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > > 2- Make virtio use the DMA API with our custom platform-provided
> > > swiotlb callbacks when needed, that is when not using IOMMU *and*
> > > running on a s
On Fri, 2018-08-03 at 00:05 -0700, Christoph Hellwig wrote:
> > 2- Make virtio use the DMA API with our custom platform-provided
> > swiotlb callbacks when needed, that is when not using IOMMU *and*
> > running on a secure VM in our case.
>
> And total NAK the customer platform-provided part of
On Thu, Aug 02, 2018 at 11:53:08PM +0300, Michael S. Tsirkin wrote:
> > We don't need cache flushing tricks.
>
> You don't but do real devices on same platform need them?
IBMs power plaforms are always cache coherent. There are some powerpc
platforms have not cache coherent DMA, but I guess this
On Thu, Aug 02, 2018 at 04:13:09PM -0500, Benjamin Herrenschmidt wrote:
> So let's differenciate the two problems of having an IOMMU (real or
> emulated) which indeeds adds overhead etc... and using the DMA API.
>
> At the moment, virtio does this all over the place:
>
> if (use_dma_api)
>
On 2018年08月03日 04:55, Michael S. Tsirkin wrote:
On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
This patch series is the follow up on the discussions we had before about
the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
for virito devices (https://pat
On Thu, Aug 02, 2018 at 04:13:09PM -0500, Benjamin Herrenschmidt wrote:
> On Thu, 2018-08-02 at 23:52 +0300, Michael S. Tsirkin wrote:
> > > Yes, this is the purpose of Anshuman original patch (I haven't looked
> > > at the details of the patch in a while but that's what I told him to
> > > impleme
On Thu, 2018-08-02 at 23:52 +0300, Michael S. Tsirkin wrote:
> > Yes, this is the purpose of Anshuman original patch (I haven't looked
> > at the details of the patch in a while but that's what I told him to
> > implement ;-) :
> >
> > - Make virtio always use DMA ops to simplify the code path (
On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
> This patch series is the follow up on the discussions we had before about
> the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
> for virito devices (https://patchwork.kernel.org/patch/10417371/). There
> wer
On Thu, Aug 02, 2018 at 10:33:05AM -0500, Benjamin Herrenschmidt wrote:
> On Thu, 2018-08-02 at 00:56 +0300, Michael S. Tsirkin wrote:
> > > but it's not, VMs are
> > > created in "legacy" mode all the times and we don't know at VM creation
> > > time whether it will become a secure VM or not. The
On Thu, Aug 02, 2018 at 12:53:41PM -0500, Benjamin Herrenschmidt wrote:
> On Thu, 2018-08-02 at 20:19 +0300, Michael S. Tsirkin wrote:
> >
> > I see. So yes, given that device does not know or care, using
> > virtio features is an awkward fit.
> >
> > So let's say as a quick fix for you maybe we
On Thu, 2018-08-02 at 20:19 +0300, Michael S. Tsirkin wrote:
>
> I see. So yes, given that device does not know or care, using
> virtio features is an awkward fit.
>
> So let's say as a quick fix for you maybe we could generalize the
> xen_domain hack, instead of just checking xen_domain check so
On Thu, Aug 02, 2018 at 11:01:26AM -0500, Benjamin Herrenschmidt wrote:
> On Thu, 2018-08-02 at 18:41 +0300, Michael S. Tsirkin wrote:
> >
> > > I don't completely agree:
> > >
> > > 1 - VIRTIO_F_IOMMU_PLATFORM is a property of the "other side", ie qemu
> > > for example. It indicates that the pe
On Thu, 2018-08-02 at 18:41 +0300, Michael S. Tsirkin wrote:
>
> > I don't completely agree:
> >
> > 1 - VIRTIO_F_IOMMU_PLATFORM is a property of the "other side", ie qemu
> > for example. It indicates that the peer bypasses the normal platform
> > iommu. The platform code in the guest has no rea
On Thu, Aug 02, 2018 at 10:24:57AM -0500, Benjamin Herrenschmidt wrote:
> On Wed, 2018-08-01 at 01:36 -0700, Christoph Hellwig wrote:
> > We just need to figure out how to deal with devices that deviate
> > from the default. One things is that VIRTIO_F_IOMMU_PLATFORM really
> > should become VIRTI
On Thu, 2018-08-02 at 00:56 +0300, Michael S. Tsirkin wrote:
> > but it's not, VMs are
> > created in "legacy" mode all the times and we don't know at VM creation
> > time whether it will become a secure VM or not. The way our secure VMs
> > work is that they start as a normal VM, load a secure "pa
On Wed, 2018-08-01 at 01:36 -0700, Christoph Hellwig wrote:
> We just need to figure out how to deal with devices that deviate
> from the default. One things is that VIRTIO_F_IOMMU_PLATFORM really
> should become VIRTIO_F_PLATFORM_DMA to cover the cases of non-iommu
> dma tweaks (offsets, cache fl
On Wed, Aug 01, 2018 at 10:05:35AM +0100, Will Deacon wrote:
> Hi Christoph,
>
> On Wed, Aug 01, 2018 at 01:36:39AM -0700, Christoph Hellwig wrote:
> > On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> > > On arm/arm64, the problem we have is that legacy virtio devices on the
> > > M
On Wed, Aug 01, 2018 at 01:36:39AM -0700, Christoph Hellwig wrote:
> On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> > On arm/arm64, the problem we have is that legacy virtio devices on the MMIO
> > transport (so definitely not PCI) have historically been advertised by qemu
> > as no
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
Hi Christoph,
On Wed, Aug 01, 2018 at 01:36:39AM -0700, Christoph Hellwig wrote:
> On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> > On arm/arm64, the problem we have is that legacy virtio devices on the MMIO
> > transport (so definitely not PCI) have historically been advertised by
On Wed, Aug 01, 2018 at 09:16:38AM +0100, Will Deacon wrote:
> On arm/arm64, the problem we have is that legacy virtio devices on the MMIO
> transport (so definitely not PCI) have historically been advertised by qemu
> as not being cache coherent, but because the virtio core has bypassed DMA
> ops
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
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 is visible to the driver,
On Mon, Jul 30, 2018 at 04:26:32PM +0300, Michael S. Tsirkin wrote:
> Real hardware would reuse parts of the interface but by necessity it
> needs to behave slightly differently on some platforms. However for
> some platforms (such as x86) a PV virtio driver will by luck work with a
> PCI device b
On Mon, Jul 30, 2018 at 04:18:02AM -0700, Christoph Hellwig wrote:
> On Mon, Jul 30, 2018 at 01:28:03PM +0300, Michael S. Tsirkin wrote:
> > Let me reply to the "crappy" part first:
> > So virtio devices can run on another CPU or on a PCI bus. Configuration
> > can happen over mupltiple transports.
On Mon, Jul 30, 2018 at 01:28:03PM +0300, Michael S. Tsirkin wrote:
> Let me reply to the "crappy" part first:
> So virtio devices can run on another CPU or on a PCI bus. Configuration
> can happen over mupltiple transports. There is a discovery protocol to
> figure out where it is. It has some wa
On Mon, Jul 30, 2018 at 02:34:14AM -0700, Christoph Hellwig wrote:
> We really need to distinguish between legacy virtual crappy
> virtio (and that includes v1) that totally ignores the bus it pretends
> to be on, and sane virtio (to be defined) that sit on a real (or
> properly emulated including
On Fri, Jul 27, 2018 at 10:58:05AM +0100, Will Deacon wrote:
>
> I just wanted to say that this patch series provides a means for us to
> force the coherent DMA ops for legacy virtio devices on arm64, which in turn
> means that we can enable the SMMU with legacy devices in our fastmodel
> emulatio
On 07/27/2018 05:01 PM, Michael S. Tsirkin wrote:
> On Wed, Jul 25, 2018 at 08:56:23AM +0530, Anshuman Khandual wrote:
>> Results with and without the patches are similar.
>
> Thanks! And another thing to try is virtio-net with
> a fast NIC backend (40G and up). Unfortunately
> at this point loopb
On Wed, Jul 25, 2018 at 08:56:23AM +0530, Anshuman Khandual wrote:
> Results with and without the patches are similar.
Thanks! And another thing to try is virtio-net with
a fast NIC backend (40G and up). Unfortunately
at this point loopback tests stress the host
scheduler too much.
--
MST
__
On 07/27/2018 03:28 PM, Will Deacon wrote:
> Hi Anshuman,
>
> On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
>> This patch series is the follow up on the discussions we had before about
>> the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
>> for virito d
Hi Anshuman,
On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
> This patch series is the follow up on the discussions we had before about
> the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
> for virito devices (https://patchwork.kernel.org/patch/10417371/
On 07/23/2018 02:38 PM, Michael S. Tsirkin wrote:
> On Mon, Jul 23, 2018 at 11:58:23AM +0530, Anshuman Khandual wrote:
>> On 07/20/2018 06:46 PM, Michael S. Tsirkin wrote:
>>> On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
This patch series is the follow up on the discussio
On Mon, Jul 23, 2018 at 11:58:23AM +0530, Anshuman Khandual wrote:
> On 07/20/2018 06:46 PM, Michael S. Tsirkin wrote:
> > On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
> >> This patch series is the follow up on the discussions we had before about
> >> the RFC titled [RFC,V2] v
On 07/20/2018 06:46 PM, Michael S. Tsirkin wrote:
> On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
>> This patch series is the follow up on the discussions we had before about
>> the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
>> for virito devices (htt
On Fri, Jul 20, 2018 at 09:29:37AM +0530, Anshuman Khandual wrote:
> This patch series is the follow up on the discussions we had before about
> the RFC titled [RFC,V2] virtio: Add platform specific DMA API translation
> for virito devices (https://patchwork.kernel.org/patch/10417371/). There
> wer
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