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author | Alex Williamson <alex.williamson@redhat.com> | 2014-02-26 22:38:40 +0400 |
---|---|---|
committer | Alex Williamson <alex.williamson@redhat.com> | 2014-02-26 22:38:40 +0400 |
commit | 9d830d47c7a756da6f0b55fa25d51eec0739eb02 (patch) | |
tree | 3f40dbe93c1b0120246eab829f33490a127e336c /virt | |
parent | 88d7ab8949427f492c39f6daf0ac67f0242a88bc (diff) | |
download | linux-9d830d47c7a756da6f0b55fa25d51eec0739eb02.tar.xz |
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>
Diffstat (limited to 'virt')
-rw-r--r-- | virt/kvm/vfio.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c index b4f9507ae650..ba1a93f935c7 100644 --- a/virt/kvm/vfio.c +++ b/virt/kvm/vfio.c @@ -59,6 +59,22 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) symbol_put(vfio_group_put_external_user); } +static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group) +{ + long (*fn)(struct vfio_group *, unsigned long); + long ret; + + fn = symbol_get(vfio_external_check_extension); + if (!fn) + return false; + + ret = fn(vfio_group, VFIO_DMA_CC_IOMMU); + + symbol_put(vfio_external_check_extension); + + return ret > 0; +} + /* * Groups can use the same or different IOMMU domains. If the same then * adding a new group may change the coherency of groups we've previously @@ -75,13 +91,10 @@ static void kvm_vfio_update_coherency(struct kvm_device *dev) mutex_lock(&kv->lock); list_for_each_entry(kvg, &kv->group_list, node) { - /* - * TODO: We need an interface to check the coherency of - * the IOMMU domain this group is using. For now, assume - * it's always noncoherent. - */ - noncoherent = true; - break; + if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) { + noncoherent = true; + break; + } } if (noncoherent != kv->noncoherent) { |