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SubjectRe: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected
On Tue, Sep 18, 2018 at 05:15:00PM -0500, Alexandru Gagniuc wrote:
> When a PCI device is gone, we don't want to send IO to it if we can
> avoid it. We expose functionality via the irq_chip structure. As
> users of that structure may not know about the underlying PCI device,
> it's our responsibility to guard against removed devices.
>
> .irq_write_msi_msg() is already guarded inside __pci_write_msi_msg().
> .irq_mask/unmask() are not. Guard them for completeness.
>
> For example, surprise removal of a PCIe device triggers teardown. This
> touches the irq_chips ops some point to disable the interrupts. I/O
> generated here can crash the system on firmware-first machines.
> Not triggering the IO in the first place greatly reduces the
> possibility of the problem occurring.
>
> Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

Applied to pci/misc for v4.21, thanks!

> ---
> drivers/pci/msi.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index f2ef896464b3..f31058fd2260 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -227,6 +227,9 @@ static void msi_set_mask_bit(struct irq_data *data, u32 flag)
> {
> struct msi_desc *desc = irq_data_get_msi_desc(data);
>
> + if (pci_dev_is_disconnected(msi_desc_to_pci_dev(desc)))
> + return;
> +
> if (desc->msi_attrib.is_msix) {
> msix_mask_irq(desc, flag);
> readl(desc->mask_base); /* Flush write to device */
> --
> 2.17.1
>

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