On Mon, Oct 12, 2026 at 01:27:12PM +0000, [email protected] wrote: > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) > to consider: > - [High] pci: pci_p2pdma_distance_many() evaluates compatibility without > applying client ATS constraints > -- > > commit 254b102fe424913edc3d5f94f8d41bc5d0de2b20 > Author: Leon Romanovsky <[email protected]> > > PCI/P2PDMA: Evaluate the ATS path for clients with ATS enabled > > P2PDMA assumes every client issues Untranslated Requests. A device with > ATS enabled may translate any address it is handed, including a bus > address, and Translation Blocking can reject its Translated Requests on > a route the Untranslated answer called usable. > > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > > index e38081f797611..a5fc622e3114f 100644 > > --- a/drivers/pci/p2pdma.c > > +++ b/drivers/pci/p2pdma.c > > [ ... ] > > > @@ -1660,10 +1706,10 @@ pci_p2pdma_map_type_tlp(struct p2pdma_provider > > *provider, struct device *dev, > > pci_p2pdma_map_type_name(type), type, provider_state); > > > > if (type == PCI_P2PDMA_MAP_UNKNOWN) > > - return calc_map_type_and_dist(pdev, client, &dist, tlp_flags, > > + type = calc_map_type_and_dist(pdev, client, &dist, tlp_flags, > > true); > > > > - return type; > > + return pci_p2pdma_client_map_type(pdev, client, per_mapping, type); > > } > > [Severity: High] > Does pci_p2pdma_distance_many() also need to apply these new ATS constraints? > > While this patch successfully updates pci_p2pdma_map_type_tlp() to evaluate > ATS > routing constraints for P2PDMA clients, pci_p2pdma_distance_many() continues > to evaluate mapping compatibility without them: > > drivers/pci/p2pdma.c:pci_p2pdma_distance_many() { > ... > pci_client = find_parent_pci_dev(clients[i]); > if (!pci_client) { > ... > map = calc_map_type_and_dist(provider, pci_client, &distance, 0, > verbose); > ... > } > > If a client has ATS enabled and its Untranslated route is usable but its > Translated route is blocked by Translation Blocking (or lacks a whitelisted > host bridge), pci_p2pdma_distance_many() evaluates the Untranslated mapping > with tlp_flags=0, and incorrectly returns success. > > When the driver subsequently attempts to map memory, the ATS-aware mapping > logic will return PCI_P2PDMA_MAP_NOT_SUPPORTED and fail unexpectedly at > runtime, breaking the API contract of the distance validation.
Yes, Sashiko is right, I'll send new version :(. Thanks > > -- > Sashiko AI review ยท > https://sashiko.dev/#/patchset/[email protected]?part=17
