On Fri, Jan 10, 2020 at 10:21:11AM -0700, Jon Derrick wrote:
> The current DMA alias implementation requires the aliased device be on
> the same PCI bus as the requester ID. This introduces an arch-specific
> mechanism to point to another PCI device when doing mapping and
> PCI DMA alias search.
>
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> ---
> arch/x86/pci/common.c | 7 +++++++
> drivers/pci/pci.c | 19 ++++++++++++++++++-
> drivers/pci/search.c | 7 +++++++
> include/linux/pci.h | 1 +
> 4 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 1e59df0..83334a5 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -736,3 +736,10 @@ int pci_ext_cfg_avail(void)
> else
> return 0;
> }
> +
> +#if IS_ENABLED(CONFIG_VMD)
> +struct pci_dev *pci_direct_dma_alias(struct pci_dev *dev)
> +{
> + return to_pci_sysdata(dev->bus)->vmd_dev;
> +}
> +#endif
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index ad746d9..1362694 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6034,7 +6034,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
> return (dev1->dma_alias_mask &&
> test_bit(dev2->devfn, dev1->dma_alias_mask)) ||
> (dev2->dma_alias_mask &&
> - test_bit(dev1->devfn, dev2->dma_alias_mask));
> + test_bit(dev1->devfn, dev2->dma_alias_mask)) ||
> + (pci_direct_dma_alias(dev1) == dev2) ||
> + (pci_direct_dma_alias(dev2) == dev1);
No need for the inner braces here.
