Re: [patch V2 19/23] PCI/MSI: Sanitize MSIX table map handling

Bjorn Helgaas
2021-12-07T21:01:49Z

On Mon, Dec 06, 2021 at 11:27:54PM +0100, Thomas Gleixner wrote:
> Unmapping the MSIX base mapping in the loops which allocate/free MSI
> desciptors is daft and in the way of allowing runtime expansion of MSI-X
> descriptors.

s/MSIX/MSI-X/ (subject and first use in commit log)
s/desciptors/descriptors/

> Store the mapping in struct pci_dev and free it after freeing the MSI-X
> descriptors.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Juergen Gross <jgross@suse.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
> drivers/pci/msi/msi.c | 18 ++++++++----------
> include/linux/pci.h | 1 +
> 2 files changed, 9 insertions(+), 10 deletions(-)
>
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -241,14 +241,14 @@ static void free_msi_irqs(struct pci_dev
> pci_msi_teardown_msi_irqs(dev);
>
> list_for_each_entry_safe(entry, tmp, msi_list, list) {
> - if (entry->pci.msi_attrib.is_msix) {
> - if (list_is_last(&entry->list, msi_list))
> - iounmap(entry->pci.mask_base);
> - }
> -
> list_del(&entry->list);
> free_msi_entry(entry);
> }
> +
> + if (dev->msix_base) {
> + iounmap(dev->msix_base);
> + dev->msix_base = NULL;
> + }
> }
>
> static void pci_intx_for_msi(struct pci_dev *dev, int enable)
> @@ -501,10 +501,6 @@ static int msix_setup_entries(struct pci
> for (i = 0, curmsk = masks; i < nvec; i++) {
> entry = alloc_msi_entry(&dev->dev, 1, curmsk);
> if (!entry) {
> - if (!i)
> - iounmap(base);
> - else
> - free_msi_irqs(dev);
> /* No enough memory. Don't try again */
> ret = -ENOMEM;
> goto out;
> @@ -602,12 +598,14 @@ static int msix_capability_init(struct p
> goto out_disable;
> }
>
> + dev->msix_base = base;
> +
> /* Ensure that all table entries are masked. */
> msix_mask_all(base, tsize);
>
> ret = msix_setup_entries(dev, base, entries, nvec, affd);
> if (ret)
> - goto out_disable;
> + goto out_free;
>
> ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
> if (ret)
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -473,6 +473,7 @@ struct pci_dev {
> u8 ptm_granularity;
> #endif
> #ifdef CONFIG_PCI_MSI
> + void __iomem *msix_base;
> const struct attribute_group **msi_irq_groups;
> #endif
> struct pci_vpd vpd;
>