On Fri, Dec 17, 2021 at 02:36:58PM +0800, Lu Baolu wrote:
> The pci_dma_configure() marks the iommu_group as containing only devices
> with kernel drivers that manage DMA.
I'm looking at pci_dma_configure(), and I don't see the connection to
iommu_groups.
> Avoid this default behavior for the
> pci_stub because it does not program any DMA itself. This allows the
> pci_stub still able to be used by the admin to block driver binding after
> applying the DMA ownership to vfio.
>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci-stub.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/pci-stub.c b/drivers/pci/pci-stub.c
> index e408099fea52..6324c68602b4 100644
> --- a/drivers/pci/pci-stub.c
> +++ b/drivers/pci/pci-stub.c
> @@ -36,6 +36,9 @@ static struct pci_driver stub_driver = {
> .name = "pci-stub",
> .id_table = NULL, /* only dynamic id's */
> .probe = pci_stub_probe,
> + .driver = {
> + .suppress_auto_claim_dma_owner = true,
The new .suppress_auto_claim_dma_owner controls whether we call
iommu_device_set_dma_owner(). I guess you added
.suppress_auto_claim_dma_owner because iommu_device_set_dma_owner()
must be done *before* we call the driver's .probe() method?
Otherwise, we could call some new interface from .probe() instead of
adding the flag to struct device_driver.
> + },
> };
>
> static int __init pci_stub_init(void)
> --
> 2.25.1
>
