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

[Tian, Kevin]

> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> 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@xxxxxxxxxxxxx>
> ---
>  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.