On Tue, Nov 24, 2020 at 04:20:35PM +0530, Vidya Sagar wrote:
> There are devices (Ex:- Marvell SATA controller) that don't support
> 64-bit MSIs and the same is advertised through their MSI capability
> register. Set no_64bit_msi flag explicitly for such devices in the
> MSI setup code so that the msi_verify_entries() API would catch
> if the MSI arch code tries to use 64-bit MSI.
This seems good to me. I'll post a possible revision to set
dev->no_64bit_msi in the device enumeration path instead of in the IRQ
allocation path, since it's really a property of the device, not of
the msi_desc.
I like the extra checking this gives us. Was this prompted by
tripping over something, or is it something you noticed by code
reading? If the former, a hint about what was wrong and how it's
being fixed would be useful.
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> ---
> V2:
> * Addressed Bjorn's comment and changed the error message
>
> drivers/pci/msi.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index d52d118979a6..8de5ba6b4a59 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -581,10 +581,12 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
> entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> entry->msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
>
> - if (control & PCI_MSI_FLAGS_64BIT)
> + if (control & PCI_MSI_FLAGS_64BIT) {
> entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> - else
> + } else {
> entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
> + dev->no_64bit_msi = 1;
> + }
>
> /* Save the initial mask status */
> if (entry->msi_attrib.maskbit)
> @@ -602,8 +604,9 @@ static int msi_verify_entries(struct pci_dev *dev)
> for_each_pci_msi_entry(entry, dev) {
> if (!dev->no_64bit_msi || !entry->msg.address_hi)
> continue;
> - pci_err(dev, "Device has broken 64-bit MSI but arch"
> - " tried to assign one above 4G\n");
> + pci_err(dev, "Device has either broken 64-bit MSI or "
> + "only 32-bit MSI support but "
> + "arch tried to assign one above 4G\n");
> return -EIO;
> }
> return 0;
> --
> 2.17.1
>
