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

From: Marc Zyngier <marc.zyngier@arm.com>
To: linux-pci@vger.kernel.org,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <helgaas@google.com>
Cc: Trent Piepho <tpiepho@impinj.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
	faiz_abbas@ti.com, Joao Pinto <Joao.Pinto@synopsys.com>,
	Vignesh R <vigneshr@ti.com>
Subject: [PATCH 0/3] PCI: designware: Fixing MSI handling flow
Date: Tue, 13 Nov 2018 22:57:31 +0000	[thread overview]
Message-ID: <20181113225734.8026-1-marc.zyngier@arm.com> (raw)

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(-)

-- 
2.19.1