Commit graph

4 commits

Author SHA1 Message Date
Alex Williamson
9d830d47c7 kvm/vfio: Support for DMA coherent IOMMUs
VFIO now has support for using the IOMMU_CACHE flag and a mechanism
for an external user to test the current operating mode of the IOMMU.
Add support for this to the kvm-vfio pseudo device so that we only
register noncoherent DMA when necessary.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-26 11:38:40 -07:00
Paul Bolle
e81d1ad327 kvm: vfio: silence GCC warning
Building vfio.o triggers a GCC warning (when building for 32 bits x86):
    arch/x86/kvm/../../../virt/kvm/vfio.c: In function 'kvm_vfio_set_group':
    arch/x86/kvm/../../../virt/kvm/vfio.c:104:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
      void __user *argp = (void __user *)arg;
                          ^

Silence this warning by casting arg to unsigned long.

argp's current type, "void __user *", is always casted to "int32_t
__user *". So its type might as well be changed to "int32_t __user *".

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-01-15 12:01:48 +01:00
Alex Williamson
e0f0bbc527 kvm: Create non-coherent DMA registeration
We currently use some ad-hoc arch variables tied to legacy KVM device
assignment to manage emulation of instructions that depend on whether
non-coherent DMA is present.  Create an interface for this, adapting
legacy KVM device assignment and adding VFIO via the KVM-VFIO device.
For now we assume that non-coherent DMA is possible any time we have a
VFIO group.  Eventually an interface can be developed as part of the
VFIO external user interface to query the coherency of a group.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-30 19:02:23 +01:00
Alex Williamson
ec53500fae kvm: Add VFIO device
So far we've succeeded at making KVM and VFIO mostly unaware of each
other, but areas are cropping up where a connection beyond eventfds
and irqfds needs to be made.  This patch introduces a KVM-VFIO device
that is meant to be a gateway for such interaction.  The user creates
the device and can add and remove VFIO groups to it via file
descriptors.  When a group is added, KVM verifies the group is valid
and gets a reference to it via the VFIO external user interface.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-30 19:02:03 +01:00