Re: [PATCH 06/14] PCI/P2PDMA: Add whitelist support for Intel Host Bridges

Jason Gunthorpe
2019-07-25T18:52:41Z

On Mon, Jul 22, 2019 at 05:08:51PM -0600, Logan Gunthorpe wrote:
> Intel devices do not have good support for P2P requests that span
> different host bridges as the transactions will cross the QPI/UPI bus
> and this does not perform well.
>
> Therefore, enable support for these devices only if the host bridges
> match.
>
> Adds the Intel device's that have been tested to work. There are
> likely many others out there that will need to be tested and added.
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> drivers/pci/p2pdma.c | 36 ++++++++++++++++++++++++++++++++----
> 1 file changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index dfb802afc8ca..143e11d2a5c3 100644
> +++ b/drivers/pci/p2pdma.c
> @@ -250,9 +250,28 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
> seq_buf_printf(buf, "%s;", pci_name(pdev));
> }
>
> -static bool __host_bridge_whitelist(struct pci_host_bridge *host)
> +static const struct pci_p2pdma_whitelist_entry {
> + unsigned short vendor;
> + unsigned short device;
> + bool req_same_host_bridge;

This would be more readable in the initializer as a flags not a bool

Jason