linux-kernel - RE: [patch 01/39] PCI/MSI: Check for MSI enabled in __pci_msix

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Message-ID: <BN9PR11MB5276733F02CD0D9F2CE1B1E58C099@BN9PR11MB5276.namprd11.prod.outlook.com>
Date:   Fri, 18 Nov 2022 07:35:15 +0000
From:   "Tian, Kevin" <kevin.tian@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
CC:     "x86@...nel.org" <x86@...nel.org>, Joerg Roedel <joro@...tes.org>,
        "Will Deacon" <will@...nel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "Lorenzo Pieralisi" <lorenzo.pieralisi@....com>,
        Marc Zyngier <maz@...nel.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        Jason Gunthorpe <jgg@...lanox.com>,
        "Jiang, Dave" <dave.jiang@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        "Raj, Ashok" <ashok.raj@...el.com>, Jon Mason <jdmason@...zu.us>,
        Allen Hubbe <allenbh@...il.com>,
        "Michael Ellerman" <mpe@...erman.id.au>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "Ahmed S. Darwish" <darwi@...utronix.de>,
        "Chatre, Reinette" <reinette.chatre@...el.com>
Subject: RE: [patch 01/39] PCI/MSI: Check for MSI enabled in
 __pci_msix_enable()

> From: Thomas Gleixner <tglx@...utronix.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@...utronix.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.