Re: 0b6bacc7874f - main - Add ofw_bus_iommu_map() that maps PCI requester ID to an IOMMU specifier based on "iommu-map" DTS property.
Date: Fri, 06 May 2022 16:44:24 UTC
On Fri, May 06, 2022 at 09:25:40AM -0700, Ravi Pokala wrote:
> -----Original Message-----
> From: <owner-src-committers@freebsd.org> on behalf of Ruslan Bukin <br@FreeBSD.org>
> Date: 2022-05-06, Friday at 08:51
> To: <src-committers@FreeBSD.org>, <dev-commits-src-all@FreeBSD.org>, <dev-commits-src-main@FreeBSD.org>
> Subject: git: 0b6bacc7874f - main - Add ofw_bus_iommu_map() that maps PCI requester ID to an IOMMU specifier based on "iommu-map" DTS property.
>
> The branch main has been updated by br:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=0b6bacc7874f9c68ad35b06f1a7614171eb9ab10
>
> commit 0b6bacc7874f9c68ad35b06f1a7614171eb9ab10
> Author: Ruslan Bukin <br@FreeBSD.org>
> AuthorDate: 2022-05-06 15:41:11 +0000
> Commit: Ruslan Bukin <br@FreeBSD.org>
> CommitDate: 2022-05-06 15:48:04 +0000
>
> Add ofw_bus_iommu_map() that maps PCI requester ID to an IOMMU
> specifier based on "iommu-map" DTS property.
>
> Sponsored by: UKRI
> ---
> sys/dev/ofw/ofw_bus_subr.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> sys/dev/ofw/ofw_bus_subr.h | 3 ++-
> 2 files changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/sys/dev/ofw/ofw_bus_subr.c b/sys/dev/ofw/ofw_bus_subr.c
> index ea57d1086779..408d554b3c7f 100644
> --- a/sys/dev/ofw/ofw_bus_subr.c
> +++ b/sys/dev/ofw/ofw_bus_subr.c
> @@ -491,6 +491,50 @@ ofw_bus_msimap(phandle_t node, uint16_t pci_rid, phandle_t *msi_parent,
> return (err);
> }
>
> +int
> +ofw_bus_iommu_map(phandle_t node, uint16_t pci_rid, phandle_t *iommu_parent,
> + uint32_t *iommu_rid)
> +{
> + pcell_t mask, iommu_base, rid_base, rid_length;
> + uint32_t masked_rid;
> + pcell_t map[4];
> + ssize_t len;
> + int err, i;
> +
> + len = OF_getproplen(node, "iommu-map");
> + if (len <= 0)
> + return (ENOENT);
> + if (len > sizeof(map))
> + return (ENOMEM);
> +
> + len = OF_getencprop(node, "iommu-map", map, 16);
> +
> + err = ENOENT;
> + mask = 0xffffffff;
> + OF_getencprop(node, "iommu-map-mask", &mask, sizeof(mask));
> +
> + masked_rid = pci_rid & mask;
> + for (i = 0; i < len; i += 4) {
> + rid_base = map[i + 0];
> + rid_length = map[i + 3];
>
> Hi Ruslan,
>
> I'm confused by this. 'map' is declared as a 4-element array, which means 'map[i + 0]' and 'map[i + 3]' are both only valid when 'i' is 0. But 'i' is the loop iterator; doesn't that mean you're accessing outside the array after the 0th time through the loop?
>
> Thanks,
Thanks, I'll fix this. I did not want to allocate memory here but it looks like we have to, since there is no limit on amount of entires in "iommu-map" property.
>
> Ravi (rpokala@)
>
> + if (masked_rid < rid_base ||
> + masked_rid >= (rid_base + rid_length))
> + continue;
> +
> + iommu_base = map[i + 2];
> +
> + if (iommu_parent != NULL)
> + *iommu_parent = map[i + 1];
> + if (iommu_rid != NULL)
> + *iommu_rid = masked_rid - rid_base + iommu_base;
> + err = 0;
> + break;
> + }
> +
> + return (err);
> +}
> +
> static int
> ofw_bus_reg_to_rl_helper(device_t dev, phandle_t node, pcell_t acells, pcell_t scells,
> struct resource_list *rl, const char *reg_source)
> diff --git a/sys/dev/ofw/ofw_bus_subr.h b/sys/dev/ofw/ofw_bus_subr.h
> index 45709c92c1f7..89f291f92373 100644
> --- a/sys/dev/ofw/ofw_bus_subr.h
> +++ b/sys/dev/ofw/ofw_bus_subr.h
> @@ -92,8 +92,9 @@ int ofw_bus_lookup_imap(phandle_t, struct ofw_bus_iinfo *, void *, int,
> int ofw_bus_search_intrmap(void *, int, void *, int, void *, int, void *,
> void *, void *, int, phandle_t *);
>
> -/* Routines for processing msi maps */
> +/* Routines for processing msi and iommu maps. */
> int ofw_bus_msimap(phandle_t, uint16_t, phandle_t *, uint32_t *);
> +int ofw_bus_iommu_map(phandle_t, uint16_t, phandle_t *, uint32_t *);
>
> /* Routines for parsing device-tree data into resource lists. */
> int ofw_bus_reg_to_rl(device_t, phandle_t, pcell_t, pcell_t,
>
>