On Mon, Sep 14, 2020 at 01:32:55PM -0400, Jon Derrick wrote:
> Client VMD platforms have a software-triggered MSI/X vector 0 that will
> not forward hardware-remapped MSI/X vectors from the sub-device domain.
> This causes an issue with VMD platforms that use AHCI behind VMD and
> have a single MSI/X vector mapping to vector 0. Add an MSI/X vector
> offset for these platforms.
>
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> ---
> drivers/pci/controller/vmd.c | 35 +++++++++++++++++++++++++----------
> 1 file changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index f69ef8c89f72..f8195bad79d1 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -53,6 +53,12 @@ enum vmd_features {
> * vendor-specific capability space
> */
> VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP = (1 << 2),
> +
> + /*
> + * Device may use MSI/X vector 0 for software triggering and will not
> + * be used for MSI/X remapping
> + */
> + VMD_FEAT_OFFSET_FIRST_VECTOR = (1 << 3),
> };
>
> /*
> @@ -104,6 +110,7 @@ struct vmd_dev {
> struct irq_domain *irq_domain;
> struct pci_bus *bus;
> u8 busn_start;
> + u8 first_vec;
> };
>
> static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
> @@ -199,25 +206,26 @@ static irq_hw_number_t vmd_get_hwirq(struct msi_domain_info *info,
> */
> static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *desc)
> {
> - int i, best = 1;
> unsigned long flags;
> + int i, best;
>
> if (vmd->msix_count == 1)
This condition needs account for the vector offset, right?
if (vmd->msix_count == 1 + vmd->first_vec))
> - return &vmd->irqs[0];
> + return &vmd->irqs[vmd->first_vec];
