linux-kernel - Re: [PATCH v5 2/2] PCI: dwc: Fix MSI page leakage in suspend/resume

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Date:   Wed, 7 Oct 2020 12:41:19 -0500
From:   Rob Herring <robh@...nel.org>
To:     Jisheng Zhang <Jisheng.Zhang@...aptics.com>
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        linux-omap@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/2] PCI: dwc: Fix MSI page leakage in suspend/resume

On Wed, Sep 30, 2020 at 09:15:25AM +0800, Jisheng Zhang wrote:
> Currently, dw_pcie_msi_init() allocates and maps page for msi, then
> program the PCIE_MSI_ADDR_LO and PCIE_MSI_ADDR_HI. The Root Complex
> may lose power during suspend-to-RAM, so when we resume, we want to
> redo the latter but not the former. If designware based driver (for
> example, pcie-tegra194.c) calls dw_pcie_msi_init() in resume path, the
> msi page will be leaked.
> 
> As pointed out by Rob and Ard, there's no need to allocate a page for
> the MSI address, we could use an address in the driver data.
> 
> To avoid map the MSI msg again during resume, we move the map MSI msg
> from dw_pcie_msi_init() to dw_pcie_host_init().
> 
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
> ---
>  drivers/pci/controller/dwc/pci-dra7xx.c       | 18 ++++++++++-
>  .../pci/controller/dwc/pcie-designware-host.c | 32 +++++++++----------
>  drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
>  3 files changed, 34 insertions(+), 18 deletions(-)

I'm working on some larger MSI clean-ups which should eliminate the 
dra7xx addition, but this is good enough for now.

Reviewed-by: Rob Herring <robh@...nel.org>