| Message ID | 2-v1-ef02c60ddb76+12ca2-intel_no_snoop_jgg@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Wed, Apr 06, 2022 at 07:02:36AM +0000, Tian, Kevin wrote: > > So like this: > > > > int vfio_register_group_dev(struct vfio_device *device) > > { > > + if (!dev_is_dma_coherent(device->dev)) > > + return -EINVAL; > > + > > return __vfio_register_dev(device, > > vfio_group_find_or_alloc(device->dev)); > > } > > > > I fixed it up. > > > > if that is the case should it also apply to usnic and vdpa in the first > patch (i.e. fail the probe)? Ideally, but I don't want to mess with existing logic in these drivers.. Thanks, Jason
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index a4555014bd1e72..2a3aa3e742d943 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -32,6 +32,7 @@ #include <linux/vfio.h> #include <linux/wait.h> #include <linux/sched/signal.h> +#include <linux/dma-map-ops.h> #include "vfio.h" #define DRIVER_VERSION "0.3" @@ -1348,6 +1349,11 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) if (IS_ERR(device)) return PTR_ERR(device); + if (group->type == VFIO_IOMMU && !dev_is_dma_coherent(device->dev)) { + ret = -ENODEV; + goto err_device_put; + } + if (!try_module_get(device->dev->driver->owner)) { ret = -ENODEV; goto err_device_put;
dev_is_dma_coherent() is the control to determine if IOMMU_CACHE can be supported. IOMMU_CACHE means that normal DMAs do not require any additional coherency mechanism and is the basic uAPI that VFIO exposes to userspace. For instance VFIO applications like DPDK will not work if additional coherency operations are required. Therefore check dev_is_dma_coherent() before allowing a device to join a domain. This will block device/platform/iommu combinations from using VFIO that do not support cache coherent DMA. Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> --- drivers/vfio/vfio.c | 6 ++++++ 1 file changed, 6 insertions(+)