On Fri, Jul 04, 2025 at 03:08:03PM +0800, Jiqian Chen wrote:
> When init_msix() fails, current logic return fail and free MSIX-related
> resources in vpci_deassign_device(). But the previous new changes will
> hide MSIX capability and return success, it can't reach
> vpci_deassign_device() to remove resources if hiding success, so those
> resources must be removed in cleanup function of MSIX.
>
> To do that, implement cleanup function for MSIX.
>
> Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
> ---
> cc: "Roger Pau Monné" <roger....@citrix.com>
> ---
> v6->v7 changes:
> * Change the pointer parameter of cleanup_msix() to be const.
> * When vpci_remove_registers() in cleanup_msix() fails, not to return
> directly, instead try to free msix and re-add ctrl handler.
> * Pass pdev->vpci into vpci_add_register() instead of pdev->vpci->msix in
> init_msix() since we need that every handler realize that msix is NULL
> when msix is freed but handlers are still in there.
>
> v5->v6 changes:
> * Change the logic to add dummy handler when !vpci->msix in cleanup_msix().
>
> v4->v5 changes:
> * Change definition "static void cleanup_msix" to "static int cf_check
> cleanup_msix"
> since cleanup hook is changed to be int.
> * Add a read-only register for MSIX Control Register in the end of
> cleanup_msix().
>
> v3->v4 changes:
> * Change function name from fini_msix() to cleanup_msix().
> * Change to use XFREE to free vpci->msix.
> * In cleanup function, change the sequence of check and remove action
> according to
> init_msix().
>
> v2->v3 changes:
> * Remove unnecessary clean operations in fini_msix().
>
> v1->v2 changes:
> new patch.
>
> Best regards,
> Jiqian Chen.
> ---
> xen/drivers/vpci/msix.c | 54 ++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 50 insertions(+), 4 deletions(-)
>
> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
> index a1692b9d9f6a..114280337f3f 100644
> --- a/xen/drivers/vpci/msix.c
> +++ b/xen/drivers/vpci/msix.c
> @@ -36,7 +36,11 @@
> static uint32_t cf_check control_read(
> const struct pci_dev *pdev, unsigned int reg, void *data)
> {
> - const struct vpci_msix *msix = data;
> + const struct vpci *vpci = data;
> + const struct vpci_msix *msix = vpci->msix;
> +
> + if ( !msix )
> + return pci_conf_read16(pdev->sbdf, reg);
>
> return (msix->max_entries - 1) |
> (msix->enabled ? PCI_MSIX_FLAGS_ENABLE : 0) |
> @@ -74,12 +78,16 @@ static void update_entry(struct vpci_msix_entry *entry,
> static void cf_check control_write(
> const struct pci_dev *pdev, unsigned int reg, uint32_t val, void *data)
> {
> - struct vpci_msix *msix = data;
> + struct vpci *vpci = data;
> + struct vpci_msix *msix = vpci->msix;
> bool new_masked = val & PCI_MSIX_FLAGS_MASKALL;
> bool new_enabled = val & PCI_MSIX_FLAGS_ENABLE;
> unsigned int i;
> int rc;
>
> + if ( !msix )
> + return;
> +
> if ( new_masked == msix->masked && new_enabled == msix->enabled )
> return;
>
> @@ -656,6 +664,44 @@ static int vpci_make_msix_hole(const struct pci_dev
> *pdev)
> return 0;
> }
>
> +static int cf_check cleanup_msix(const struct pci_dev *pdev)
> +{
> + int rc;
> + struct vpci *vpci = pdev->vpci;
> + const unsigned int msix_pos = pdev->msix_pos;
> +
> + if ( !msix_pos )
> + return 0;
> +
> + rc = vpci_remove_registers(vpci, msix_control_reg(msix_pos), 2);
> + if ( rc )
> + printk(XENLOG_WARNING "%pd %pp: fail to remove MSIX handlers
> rc=%d\n",
> + pdev->domain, &pdev->sbdf, rc);
The same comment as in the previous patch: vpci_remove_registers()
returning an error would likely imply memory corruption, and hence
it's best to just return error and avoid having to modify the
handlers.
Thanks, Roger.
