Re: [PATCH v1 1/1] PCI: dwc: Fix MSI msi_msg dma mapping

[Rob Herring <robh@kernel.org>]

On Wed, May 25, 2022 at 10:33:16PM +0000, Will McVicker wrote:
> As of commit 07940c369a6b ("PCI: dwc: Fix MSI page leakage in
> suspend/resume"), the PCIe designware host driver has been using the
> driver data allocation for the msi_msg dma mapping which can result in
> a DMA_MAPPING_ERROR due to the DMA overflow check in
> dma_direct_map_page() when the address is greater than 32-bits (reported
> in [1]). The commit was trying to address a memory leak on
> suspend/resume by moving the MSI mapping to dw_pcie_host_init(), but
> subsequently dropped the page allocation thinking it wasn't needed.
> 
> To fix the DMA mapping issue as well as make msi_msg DMA'able, let's
> switch back to allocating a 32-bit page for the msi_msg. To avoid the
> suspend/resume leak, we can allocate the page in dw_pcie_host_init()
> since that function shouldn't be called during suspend/resume.
> 
> [1] https://lore.kernel.org/all/Yo0soniFborDl7+C@google.com/
> 
> Signed-off-by: Will McVicker <willmcvicker@google.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++++++++------
>  drivers/pci/controller/dwc/pcie-designware.h      |  2 +-
>  2 files changed, 9 insertions(+), 7 deletions(-)

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