Re: [PATCH] PCI: dwc: ep: Fix regression in dw_pcie_ep_raise_msi_irq()

[Niklas Cassel <cassel@kernel.org>]

On Wed, Feb 25, 2026 at 08:31:24PM +0530, Manivannan Sadhasivam wrote:
> On Tue, Feb 10, 2026 at 07:12:25PM +0100, Niklas Cassel wrote:
> > When using the nvmet-pci-epf EPF driver, and starting the EP before
> > starting a host with UEFI, the UEFI performs NVMe commands e.g.
> > Identify Controller, to get the name of the controller.
> > 
> > nvmet-pci-epf will post the CQE (completion queue entry) to the Admin
> > Completion Queue, and then raise an IRQ (using
> > dw_pcie_ep_raise_msi_irq()).
> > 
> > Once the host boots Linux, we will see a WARN_ON_ONCE() from
> > dw_pcie_ep_raise_msi_irq(), and then the booting of the host hangs,
> > because it never gets an IRQ when loading the nvme driver.
> > 
> > The reason is that the MSI target address used by UEFI and Linux might
> > be different, which will cause dw_pcie_ep_raise_msi_irq() to simply
> > return -EINVAL.
> > 
> > This was working before commit 8719c64e76bf ("PCI: dwc: ep: Cache MSI
> > outbound iATU mapping"), so this is a regression.
> > 
> > Also, remove the warning, as we cannot know if there are operations in
> > flight or not, so it seems wrong to print this warning unconditionally
> > at every boot when e.g. nvmet-pci-epf is used with a host with UEFI.
> > 
> > Fixes: 8719c64e76bf ("PCI: dwc: ep: Cache MSI outbound iATU mapping")
> > Signed-off-by: Niklas Cassel <cassel@kernel.org>
> 
> Acked-by: Manivannan Sadhasivam <mani@kernel.org>
> 
> Bjorn, since this patch fixes a regression introduced in v7.0, could you please
> take it for current -rc?


While not introduced in v7.0, it would be nice if you could also consider:
https://patchwork.kernel.org/project/linux-pci/patch/20260211175540.105677-2-cassel@kernel.org/

(Such that v7.0 could have both working dw_pcie_ep_raise_msix_irq() and
dw_pcie_ep_raise_msi_irq())


Kind regards,
Niklas