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[PATCH v8 4/8] virtio-iommu: set supported page size mask

Bharat Bhushan posted 8 patches 5 years, 8 months ago
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Eric Auger <eric.auger@redhat.com>
There is a newer version of this series
[PATCH v8 4/8] virtio-iommu: set supported page size mask
Posted by Bharat Bhushan 5 years, 8 months ago 
Add optional interface to set page size mask.
Currently this is set global configuration and not
per endpoint.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
---
v7->v8:
 - new patch

 hw/virtio/virtio-iommu.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 4cee8083bc..c00a55348d 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -650,6 +650,15 @@ static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
     return (ua > ub) - (ua < ub);
 }
 
+static void virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
+                                            uint64_t page_size_mask)
+{
+    IOMMUDevice *sdev = container_of(mr, IOMMUDevice, iommu_mr);
+    VirtIOIOMMU *s = sdev->viommu;
+
+    s->config.page_size_mask = page_size_mask;
+}
+
 static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -865,6 +874,7 @@ static void virtio_iommu_memory_region_class_init(ObjectClass *klass,
     IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);
 
     imrc->translate = virtio_iommu_translate;
+    imrc->iommu_set_page_size_mask = virtio_iommu_set_page_size_mask;
 }
 
 static const TypeInfo virtio_iommu_info = {
-- 
2.17.1
Re: [PATCH v8 4/8] virtio-iommu: set supported page size mask
Posted by Auger Eric 5 years, 8 months ago 
Hi Bharat,

On 3/18/20 11:11 AM, Bharat Bhushan wrote:
> Add optional interface to set page size mask.
> Currently this is set global configuration and not
> per endpoint.
> 
> Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
> ---
> v7->v8:
>  - new patch
> 
>  hw/virtio/virtio-iommu.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index 4cee8083bc..c00a55348d 100644
> --- a/hw/virtio/virtio-iommu.c
> +++ b/hw/virtio/virtio-iommu.c
> @@ -650,6 +650,15 @@ static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
>      return (ua > ub) - (ua < ub);
>  }
>  
> +static void virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
> +                                            uint64_t page_size_mask)
> +{
> +    IOMMUDevice *sdev = container_of(mr, IOMMUDevice, iommu_mr);
> +    VirtIOIOMMU *s = sdev->viommu;
> +
> +    s->config.page_size_mask = page_size_mask;
The problem is page_size_mask is global to the VIRTIO-IOMMU.

- Can't different VFIO containers impose different/inconsistent settings?
- VFIO devices can be hotplugged. So we may start with some default
page_size_mask which is latter overriden by a host imposed one. Assume
you first launch the VM with a virtio NIC. This uses 64K. Then you
hotplug a VFIO device behind a physical IOMMU which only supports 4K
pages. Isn't it a valid scenario?

Thanks

Eric

> +}
> +
>  static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
>  {
>      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> @@ -865,6 +874,7 @@ static void virtio_iommu_memory_region_class_init(ObjectClass *klass,
>      IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);
>  
>      imrc->translate = virtio_iommu_translate;
> +    imrc->iommu_set_page_size_mask = virtio_iommu_set_page_size_mask;
>  }
>  
>  static const TypeInfo virtio_iommu_info = {
>
Re: [PATCH v8 4/8] virtio-iommu: set supported page size mask
Posted by Bharat Bhushan 5 years, 8 months ago 
Hi Eric,

On Wed, Mar 18, 2020 at 4:58 PM Auger Eric <eric.auger@redhat.com> wrote:
>
> Hi Bharat,
>
> On 3/18/20 11:11 AM, Bharat Bhushan wrote:
> > Add optional interface to set page size mask.
> > Currently this is set global configuration and not
> > per endpoint.
> >
> > Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
> > ---
> > v7->v8:
> >  - new patch
> >
> >  hw/virtio/virtio-iommu.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> > index 4cee8083bc..c00a55348d 100644
> > --- a/hw/virtio/virtio-iommu.c
> > +++ b/hw/virtio/virtio-iommu.c
> > @@ -650,6 +650,15 @@ static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
> >      return (ua > ub) - (ua < ub);
> >  }
> >
> > +static void virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
> > +                                            uint64_t page_size_mask)
> > +{
> > +    IOMMUDevice *sdev = container_of(mr, IOMMUDevice, iommu_mr);
> > +    VirtIOIOMMU *s = sdev->viommu;
> > +
> > +    s->config.page_size_mask = page_size_mask;
> The problem is page_size_mask is global to the VIRTIO-IOMMU.
>
> - Can't different VFIO containers impose different/inconsistent settings?
> - VFIO devices can be hotplugged.

This is possible if we different iommu's, which we support. correct?

> So we may start with some default
> page_size_mask which is latter overriden by a host imposed one. Assume
> you first launch the VM with a virtio NIC. This uses 64K. Then you
> hotplug a VFIO device behind a physical IOMMU which only supports 4K
> pages. Isn't it a valid scenario?

So we need to expose page_size_mask per endpoint?

Thanks
-Bharat

>
> Thanks
>
> Eric
>
> > +}
> > +
> >  static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
> >  {
> >      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > @@ -865,6 +874,7 @@ static void virtio_iommu_memory_region_class_init(ObjectClass *klass,
> >      IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);
> >
> >      imrc->translate = virtio_iommu_translate;
> > +    imrc->iommu_set_page_size_mask = virtio_iommu_set_page_size_mask;
> >  }
> >
> >  static const TypeInfo virtio_iommu_info = {
> >
>
Re: [PATCH v8 4/8] virtio-iommu: set supported page size mask
Posted by Bharat Bhushan 5 years, 7 months ago 
Hi Eric/Jean,

On Wed, Mar 18, 2020 at 8:05 PM Bharat Bhushan <bharatb.linux@gmail.com> wrote:
>
> Hi Eric,
>
> On Wed, Mar 18, 2020 at 4:58 PM Auger Eric <eric.auger@redhat.com> wrote:
> >
> > Hi Bharat,
> >
> > On 3/18/20 11:11 AM, Bharat Bhushan wrote:
> > > Add optional interface to set page size mask.
> > > Currently this is set global configuration and not
> > > per endpoint.
> > >
> > > Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
> > > ---
> > > v7->v8:
> > >  - new patch
> > >
> > >  hw/virtio/virtio-iommu.c | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > >
> > > diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> > > index 4cee8083bc..c00a55348d 100644
> > > --- a/hw/virtio/virtio-iommu.c
> > > +++ b/hw/virtio/virtio-iommu.c
> > > @@ -650,6 +650,15 @@ static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
> > >      return (ua > ub) - (ua < ub);
> > >  }
> > >
> > > +static void virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
> > > +                                            uint64_t page_size_mask)
> > > +{
> > > +    IOMMUDevice *sdev = container_of(mr, IOMMUDevice, iommu_mr);
> > > +    VirtIOIOMMU *s = sdev->viommu;
> > > +
> > > +    s->config.page_size_mask = page_size_mask;
> > The problem is page_size_mask is global to the VIRTIO-IOMMU.
> >
> > - Can't different VFIO containers impose different/inconsistent settings?
> > - VFIO devices can be hotplugged.
>
> This is possible if we different iommu's, which we support. correct?
>
> > So we may start with some default
> > page_size_mask which is latter overriden by a host imposed one. Assume
> > you first launch the VM with a virtio NIC. This uses 64K. Then you
> > hotplug a VFIO device behind a physical IOMMU which only supports 4K
> > pages. Isn't it a valid scenario?
>
> So we need to expose page_size_mask per endpoint?

Just sent Linux RFC patch to use page-size-mask per endpoint.
QEMU changes are also ready, will share soon.

Thanks
-Bharat

>
> Thanks
> -Bharat
>
> >
> > Thanks
> >
> > Eric
> >
> > > +}
> > > +
> > >  static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
> > >  {
> > >      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > > @@ -865,6 +874,7 @@ static void virtio_iommu_memory_region_class_init(ObjectClass *klass,
> > >      IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);
> > >
> > >      imrc->translate = virtio_iommu_translate;
> > > +    imrc->iommu_set_page_size_mask = virtio_iommu_set_page_size_mask;
> > >  }
> > >
> > >  static const TypeInfo virtio_iommu_info = {
> > >
> >

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