Re: [PATCH v3 1/3] PCI/ATS: Ensure pci_ats_supported() is PF-aware for VFs

[Samiullah Khawaja <skhawaja@google.com>]

On Tue, May 19, 2026 at 01:53:20PM +0000, Pranjal Shrivastava wrote:
>Update pci_ats_supported() to additionally check the associated PF's
>status when called on a VF. This ensures that PF-level quirks and
>untrusted status are correctly propagated to VFs, providing a robust
>support check that aligns with the kernel's PF-centric ATS configuration
>model and is immune to the timing of VF-specific fixups.
>
>Signed-off-by: Pranjal Shrivastava <praan@google.com>
>---
> drivers/pci/ats.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
>index ec6c8dbdc5e9..a5fa7745bce8 100644
>--- a/drivers/pci/ats.c
>+++ b/drivers/pci/ats.c
>@@ -40,10 +40,13 @@ void pci_ats_init(struct pci_dev *dev)
>  */
> bool pci_ats_supported(struct pci_dev *dev)
> {
>-	if (!dev->ats_cap)
>+	if (!dev->ats_cap || dev->untrusted)
> 		return false;
>
>-	return (dev->untrusted == 0);
>+	if (dev->is_virtfn)
>+		return pci_ats_supported(pci_physfn(dev));
>+
>+	return true;
> }
> EXPORT_SYMBOL_GPL(pci_ats_supported);
>
>-- 
>2.54.0.563.g4f69b47b94-goog
>

Reviewed-by: Samiullah Khawaja <skhawaja@google.com>