Re: [PATCHv2 0/2] pci: fix msi_addr_mask on powerpc and sparc systems

Bjorn Helgaas
2026-03-03T16:30:58Z

On Tue, Mar 03, 2026 at 09:59:15AM +0530, Madhavan Srinivasan wrote:
> On 2/27/26 10:14 PM, Bjorn Helgaas wrote:
> > On Fri, Feb 20, 2026 at 12:32:26PM +0530, Nilay Shroff wrote:
> > > Hi,
> > >
> > > Recent changes [1] which replaced pci_dev::no_64bit_msi with pci_dev::
> > > msi_addr_mask inadvertently missed to initialize the pci_dev::msi_addr_mask
> > > to the DMA_BIT_MASK(64) on powerpc platform. Due to this, later the
> > > validation the programmed MSI address against the msi_addr_mask fails.
> > > This causes pci device probe method failures on powerpc platform. We also
> > > realized that similar issue could potentially happen on sparc system as
> > > well. So this series initializes pci_dev::msi_addr_mask to DMA_BIT_MASK(64)
> > > when pci_dev is instantiated for both powerpc and sparc platforms.
> > >
> > > The first patch in the series fixes this on powerpc platform. The second
> > > patch fixes this issue on sparc platform. Please note that as I don't have
> > > access to the sparc platform, this patch was only compile tested on the
> > > sparc system. Anyone from the community is welcome to test it who has
> > > access to the sparc machine.
> > >
> > > [1] https://lore.kernel.org/all/20260129-pci-msi-addr-mask-v4-0-70da998f2750@iscas.ac.cn/
> > >
> > > Changes since v1:
> > > - Initialize the pci_dev:msi_addr_mask on sparc platform (Vivian Wang)
> > > - Some minor cosmetic fixes (Bjorn Helgaas)
> > >
> > > Nilay Shroff (2):
> > > powerpc/pci: Initialize msi_addr_mask for OF-created PCI devices
> > > sparc/pci: Initialize msi_addr_mask for OF-created PCI devices
> > >
> > > arch/powerpc/kernel/pci_of_scan.c | 7 +++++++
> > > arch/sparc/kernel/pci.c | 7 +++++++
> > > 2 files changed, 14 insertions(+)
> > These fix regressions on powerpc and sparc caused by 386ced19e9a3
> > ("PCI/MSI: Convert the boolean no_64bit_msi flag to a DMA address
> > mask").
> >
> > These fixes have been tested by Han Gao (SPARC Enterprise T5220),
> > Nathaniel Roach (SPARC T5-2), and Venkat Rao Bagalkote (IBM Power
> > System LPAR (pseries)).
> >
> > It'd be great to have acks from the powerpc and sparc folks so they
>
> Sorry for the delayed response, yes we tested this from our end.
> Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>

Added your ack to the powerpc patch, thank you very much!