RE: [patch 01/39] PCI/MSI: Check for MSI enabled in __pci_msix_enable()

Tian, Kevin
2022-11-18T07:35:25Z

> From: Thomas Gleixner <tglx@linutronix.de>
> Sent: Friday, November 11, 2022 9:54 PM
>
> PCI/MSI and PCI/MSI-X are mutually exclusive, but the MSI-X enable code
> lacks a check for already enabled MSI.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> drivers/pci/msi/msi.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -935,6 +935,11 @@ static int __pci_enable_msix_range(struc
> if (maxvec < minvec)
> return -ERANGE;
>
> + if (dev->msi_enabled) {
> + pci_info(dev, "can't enable MSI-X (MSI already enabled)\n");
> + return -EINVAL;
> + }
> +
> if (WARN_ON_ONCE(dev->msix_enabled))
> return -EINVAL;
>

a same check remains in __pci_enable_msix():

/* Check whether driver already requested for MSI IRQ */
if (dev->msi_enabled) {
pci_info(dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
return -EINVAL;
}
return msix_capability_init(dev, entries, nvec, affd);

It's removed later in patch33 when sanitizing MSI-X checks. But logically
the removal can come with this patch.