Re: [PATCH v4 1/4] PCI/MSI: Conservatively generalize no_64bit_msi into msi_addr_mask
Vivian Wang <[email protected]>
| Newsgroups | dev.linux.lists.sophgo,org.freedesktop.lists.amd-gfx,org.freedesktop.lists.dri-devel,org.infradead.lists.linux-riscv,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pci,org.kernel.vger.linux-sound,org.kernel.vger.netdev,org.ozlabs.lists.linuxppc-dev |
|---|---|
| Message-ID | <[email protected]> |
On 2/27/26 02:25, Mark Bloch wrote: > On 29/01/2026 3:56, Vivian Wang wrote: >> Some PCI devices have PCI_MSI_FLAGS_64BIT in the MSI capability, but >> implement less than 64 address bits. This breaks on platforms where such >> a device is assigned an MSI address higher than what's reachable. >> >> Currently, the no_64bit_msi bit is set for these devices, meaning that >> only 32-bit MSI addresses are allowed for them. However, on some >> platforms the MSI doorbell address is above the 32-bit limit but within >> the addressable range of the device. >> >> As a first step to enabling MSI on those combinations of devices and >> platforms, conservatively generalize the single-bit flag no_64bit_msi >> into msi_addr_mask. (The name msi_addr_mask is chosen to avoid confusion >> with msi_mask.) >> >> The translation is essentially: >> >> - no_64bit_msi = 1 -> msi_addr_mask = DMA_BIT_MASK(32) >> - no_64bit_msi = 0 -> msi_addr_mask = DMA_BIT_MASK(64) >> - if (no_64bit_msi) -> if (msi_addr_mask < DMA_BIT_MASK(64)) >> > Hey Vivian, > > We are seeing issues while reloading mlx5 on a PPC64 platform. Mea culpa. There's a fix on the list [1] since last Friday. I'm not sure why it hasn't moved yet, but please take a look. Vivian "dramforever" Wang [1]: https://lore.kernel.org/all/[email protected]/