Re: [PATCH 0/3] PCI: designware: Fixing MSI handling flow

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Tue, Nov 13, 2018 at 10:57:31PM +0000, Marc Zyngier wrote:
> It recently came to light that the Designware PCIe driver is rather
> broken in the way it handles MSI[1]:
> 
> - It masks interrupt by disabling them, meaning that MSIs generated
>   during the masked window are simply lost. Oops.
> 
> - Acking of the currently pending MSI is done outside of the interrupt
>   flow, getting moved around randomly and ultimately breaking the
>   driver. Not great.
> 
> This series attempts to address this by switching to using the MASK
> register for masking interrupts (!), and move the ack into the
> appropriate callback, giving it a fixed place in the MSI handling
> flow.
> 
> Note that this is only compile-tested on my arm64 laptop, as I'm
> travelling and do not have the required HW to test it anyway. I'd
> welcome both review and testing by the interested parties (dwc
> maintainer and users affected by existing bugs).
> 
> Thanks,
> 
> 	M.
> 
> [1] https://patchwork.kernel.org/patch/10657987/
> 
> Marc Zyngier (3):
>   PCI: designware: Use interrupt masking instead of disabling
>   PCI: designware: Take lock when ACKing an interrupt
>   PCI: designware: Move interrupt acking into the proper callback
> 
>  .../pci/controller/dwc/pcie-designware-host.c | 22 ++++++++++++-------
>  1 file changed, 14 insertions(+), 8 deletions(-)

Applied to pci/dwc-msi for v4.21 with tags and minor log updates.

All, please have a look and possibly keep testing it, I will ask
Bjorn to move it into -next shortly.

Thanks,
Lorenzo