Re: [PATCH v4 1/4] PCI/MSI: Conservatively generalize no_64bit_msi into msi_addr_mask
Mark Bloch <[email protected]>
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On 27/02/2026 7:25, Vivian Wang wrote: > 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. > Thanks! I've looked at the patch, it seems fine and should fix the issue we are seeing. Mark > Vivian "dramforever" Wang > > [1]: https://lore.kernel.org/all/[email protected]/ >