From: Bjorn Helgaas <helgaas@kernel.org>
To: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Cc: linux-pci@vger.kernel.org, keith.busch@intel.com,
alex_gagniuc@dellteam.com, austin_bolen@dell.com,
shyam_iyer@dell.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected
Date: Wed, 7 Nov 2018 17:42:57 -0600 [thread overview]
Message-ID: <20181107234257.GC41183@google.com> (raw)
In-Reply-To: <20180918221501.13112-1-mr.nuke.me@gmail.com>
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
>
next prev parent reply other threads:[~2018-11-07 23:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 22:15 [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected Alexandru Gagniuc
2018-11-06 0:32 ` Alex G.
2018-11-07 17:04 ` Derrick, Jonathan
2018-11-07 23:42 ` Bjorn Helgaas [this message]
2018-11-08 20:09 ` Bjorn Helgaas
2018-11-08 21:49 ` Keith Busch
2018-11-08 22:01 ` Greg Kroah-Hartman
2018-11-08 22:32 ` Keith Busch
2018-11-08 22:42 ` Greg Kroah-Hartman
2018-11-08 22:49 ` Alex_Gagniuc
2018-11-08 22:51 ` Greg KH
2018-11-08 23:06 ` Alex_Gagniuc
2018-11-12 5:49 ` Oliver O'Halloran
2018-11-12 20:05 ` Alex_Gagniuc
2018-11-13 5:02 ` Bjorn Helgaas
2018-11-13 22:39 ` Alex_Gagniuc
2018-11-13 22:52 ` Keith Busch
2018-11-14 0:31 ` Alex_Gagniuc
2018-11-14 5:59 ` Bjorn Helgaas
2018-11-14 19:22 ` Alex_Gagniuc
2018-11-14 19:41 ` Derrick, Jonathan
2018-11-14 20:23 ` Keith Busch
2018-11-14 20:52 ` Alex_Gagniuc
2018-11-14 20:58 ` Keith Busch
2018-11-15 6:24 ` Bjorn Helgaas
2018-11-16 0:19 ` Alex_Gagniuc
2018-11-08 23:03 ` Keith Busch
2018-11-09 7:29 ` Lukas Wunner
2018-11-09 11:32 ` Greg Kroah-Hartman
2018-11-09 16:36 ` Keith Busch
2018-11-08 22:20 ` Alex_Gagniuc
2018-11-09 7:11 ` Lukas Wunner
2018-11-12 5:48 ` Oliver O'Halloran
2018-12-27 19:28 ` Alex_Gagniuc
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