similar to: [PATCH v4] virtio: new feature to detect IOMMU device quirk

The interaction between virtio and IOMMUs is messy. On most systems with virtio, physical addresses match bus addresses, and it doesn't particularly matter which one we use to program the device. On some systems, including Xen and any system with a physical device that speaks virtio behind a physical IOMMU, we must program the IOMMU for virtio DMA to work at all. On other systems, including

The interaction between virtio and IOMMUs is messy. On most systems with virtio, physical addresses match bus addresses, and it doesn't particularly matter which one we use to program the device. On some systems, including Xen and any system with a physical device that speaks virtio behind a physical IOMMU, we must program the IOMMU for virtio DMA to work at all. On other systems, including

The interaction between virtio and IOMMUs is messy. On most systems with virtio, physical addresses match bus addresses, and it doesn't particularly matter which one we use to program the device. On some systems, including Xen and any system with a physical device that speaks virtio behind a physical IOMMU, we must program the IOMMU for virtio DMA to work at all. On other systems, including

The interaction between virtio and IOMMUs is messy. On most systems with virtio, physical addresses match bus addresses, and it doesn't particularly matter which one we use to program the device. On some systems, including Xen and any system with a physical device that speaks virtio behind a physical IOMMU, we must program the IOMMU for virtio DMA to work at all. On other systems, including

On Mon, 29 Aug 2016 21:52:20 -0600 Alex Williamson <alex.williamson at redhat.com> wrote: > On Mon, 29 Aug 2016 21:23:25 -0600 > Alex Williamson <alex.williamson at redhat.com> wrote: > > > On Tue, 30 Aug 2016 05:27:17 +0300 > > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > > > Modern virtio pci devices can set

On Mon, 29 Aug 2016 21:52:20 -0600 Alex Williamson <alex.williamson at redhat.com> wrote: > On Mon, 29 Aug 2016 21:23:25 -0600 > Alex Williamson <alex.williamson at redhat.com> wrote: > > > On Tue, 30 Aug 2016 05:27:17 +0300 > > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > > > Modern virtio pci devices can set

On Mon, 18 Apr 2016 12:58:28 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote: > Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM > to signal they are safe to use with an IOMMU. > > Without this bit, exposing the device to userspace is unsafe, so probe > and fail VFIO initialization unless noiommu is enabled. > > Signed-off-by: Michael S.

On Mon, 18 Apr 2016 12:58:28 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote: > Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM > to signal they are safe to use with an IOMMU. > > Without this bit, exposing the device to userspace is unsafe, so probe > and fail VFIO initialization unless noiommu is enabled. > > Signed-off-by: Michael S.

This is an attempt to allow enabling IOMMU for DMA. Design: - new feature bit IOMMU_PLATFORM which means host won't bypass IOMMU - virtio core uses DMA API if it sees IOMMU_PLATFORM - add quirk for vfio to disable device unless IOMMU_PLATFORM is set or the no-iommu mode is enabled - while I'm not sure how it will be used, it seems like a good idea to also have

This is an attempt to allow enabling IOMMU for DMA. Design: - new feature bit IOMMU_PLATFORM which means host won't bypass IOMMU - virtio core uses DMA API if it sees IOMMU_PLATFORM - add quirk for vfio to disable device unless IOMMU_PLATFORM is set or the no-iommu mode is enabled - while I'm not sure how it will be used, it seems like a good idea to also have

On Tue, 30 Aug 2016 05:27:17 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote: > Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM > to signal they are safe to use with an IOMMU. > > Without this bit, exposing the device to userspace is unsafe, so probe > and fail VFIO initialization unless noiommu is enabled. > > Signed-off-by: Michael S.

On Tue, 30 Aug 2016 05:27:17 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote: > Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM > to signal they are safe to use with an IOMMU. > > Without this bit, exposing the device to userspace is unsafe, so probe > and fail VFIO initialization unless noiommu is enabled. > > Signed-off-by: Michael S.

On Mon, Aug 29, 2016 at 10:53:04PM -0600, Alex Williamson wrote: > On Mon, 29 Aug 2016 21:52:20 -0600 > Alex Williamson <alex.williamson at redhat.com> wrote: > > > On Mon, 29 Aug 2016 21:23:25 -0600 > > Alex Williamson <alex.williamson at redhat.com> wrote: > > > > > On Tue, 30 Aug 2016 05:27:17 +0300 > > > "Michael S. Tsirkin"

On Mon, 29 Aug 2016 21:23:25 -0600 Alex Williamson <alex.williamson at redhat.com> wrote: > On Tue, 30 Aug 2016 05:27:17 +0300 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM > > to signal they are safe to use with an IOMMU. > > > > Without this bit, exposing the device to

Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM to signal they are safe to use with an IOMMU. Without this bit, exposing the device to userspace is unsafe, so probe and fail VFIO initialization unless noiommu is enabled. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vfio/pci/vfio_pci_private.h | 1 + drivers/vfio/pci/vfio_pci.c | 14 ++++

Modern virtio pci devices can set VIRTIO_F_IOMMU_PLATFORM to signal they are safe to use with an IOMMU. Without this bit, exposing the device to userspace is unsafe, so probe and fail VFIO initialization unless noiommu is enabled. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vfio/pci/vfio_pci_private.h | 1 + drivers/vfio/pci/vfio_pci.c | 11 +++

On Tue, Jul 19, 2016 at 05:38:23AM +0300, Michael S. Tsirkin wrote: > > On other systems, including SPARC and PPC64, virtio-pci devices are > enumerated as though they are behind an IOMMU, but the virtio host > ignores the IOMMU, so we must either pretend that the IOMMU isn't > there or somehow map everything as the identity. > > Add a feature bit to detect that quirk:

Legacy virtio devices always bypassed an IOMMU, so using them with vfio was never safe. This adds a quirk detecting these and disabling VFIO unless the noiommu mode is used. At the moment, this only applies to virtio-pci devices. The patch might make sense on stable as well. Michael S. Tsirkin (2): vfio: report group noiommu status vfio: add virtio pci quirk

Legacy virtio devices always bypassed an IOMMU, so using them with vfio was never safe. This adds a quirk detecting these and disabling VFIO unless the noiommu mode is used. At the moment, this only applies to virtio-pci devices. The patch might make sense on stable as well. Michael S. Tsirkin (2): vfio: report group noiommu status vfio: add virtio pci quirk

Rename the bit to match latest virtio spec. Add a compat macro to avoid breaking existing userspace. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- arch/um/drivers/virtio_uml.c | 2 +- drivers/vdpa/ifcvf/ifcvf_base.h | 2 +- drivers/vdpa/vdpa_sim/vdpa_sim.c | 4 ++-- drivers/vhost/net.c | 4 ++-- drivers/vhost/vdpa.c | 2 +-