Hi Robin, > -----Original Message----- > From: Robin Murphy [mailto:robin.murphy@xxxxxxx] > Sent: 14 June 2021 12:15 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > Cc: Linuxarm <linuxarm@xxxxxxxxxx>; lorenzo.pieralisi@xxxxxxx; > joro@xxxxxxxxxx; wanghuiqiang <wanghuiqiang@xxxxxxxxxx>; Guohanjun > (Hanjun Guo) <guohanjun@xxxxxxxxxx>; steven.price@xxxxxxx; > Sami.Mujawar@xxxxxxx; jon@xxxxxxxxxxxxx; eric.auger@xxxxxxxxxx; > yangyicong <yangyicong@xxxxxxxxxx> > Subject: Re: [PATCH v5 1/8] ACPI/IORT: Add support for RMR node parsing > > On 2021-05-24 12:02, Shameer Kolothum wrote: > > Add support for parsing RMR node information from ACPI. > > Find associated stream id and smmu node info from the > > RMR node and populate a linked list with RMR memory > > descriptors. > > > > Signed-off-by: Shameer Kolothum > <shameerali.kolothum.thodi@xxxxxxxxxx> > > --- > > drivers/acpi/arm64/iort.c | 104 > +++++++++++++++++++++++++++++++++++++- > > 1 file changed, 103 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > > index 3912a1f6058e..fea1ffaedf3b 100644 > > --- a/drivers/acpi/arm64/iort.c > > +++ b/drivers/acpi/arm64/iort.c > > @@ -40,6 +40,19 @@ struct iort_fwnode { > > static LIST_HEAD(iort_fwnode_list); > > static DEFINE_SPINLOCK(iort_fwnode_lock); > > > > +/* > > + * One entry for IORT RMR. > > + */ > > +struct iort_rmr_entry { > > + struct list_head list; > > + u32 sid; > > + struct acpi_iort_node *smmu; > > + struct acpi_iort_rmr_desc *rmr_desc; > > + u32 flags; > > +}; > > + > > +static LIST_HEAD(iort_rmr_list); /* list of RMR regions from ACPI > */ > > + > > /** > > * iort_set_fwnode() - Create iort_fwnode and use it to register > > * iommu data in the iort_fwnode_list > > @@ -393,7 +406,8 @@ static struct acpi_iort_node > *iort_node_get_id(struct acpi_iort_node *node, > > if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT || > > node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX || > > node->type == ACPI_IORT_NODE_SMMU_V3 || > > - node->type == ACPI_IORT_NODE_PMCG) { > > + node->type == ACPI_IORT_NODE_PMCG || > > + node->type == ACPI_IORT_NODE_RMR) { > > *id_out = map->output_base; > > return parent; > > } > > @@ -1660,6 +1674,91 @@ static void __init iort_enable_acs(struct > acpi_iort_node *iort_node) > > #else > > static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { } > > #endif > > +static int iort_rmr_desc_valid(struct acpi_iort_rmr_desc *desc, u32 count) > > +{ > > + int i, j; > > + > > + for (i = 0; i < count; i++) { > > + u64 end, start = desc[i].base_address, length = desc[i].length; > > + > > + if (!IS_ALIGNED(start, SZ_64K) || !IS_ALIGNED(length, SZ_64K)) > > + return -EINVAL; > > We should certainly FW_BUG for this, but maybe it's OK to continue, > since all we should need to do is round our iommu_resv_regions to at > least PAGE_SIZE. That seems possibly better than ignoring them and > having things potentially blow up later (especially if an end user > exercises the system more thoroughly than the firmware developer tested > it, which in at least one case I've seen may be "at all"...) Ok. Will report FW_BUG but continue with a rounded addr/size. > > > + end = start + length - 1; > > + > > + /* Check for address overlap */ > > + for (j = i + 1; j < count; j++) { > > + u64 e_start = desc[j].base_address; > > + u64 e_end = e_start + desc[j].length - 1; > > + > > + if (start <= e_end && end >= e_start) > > + return -EINVAL; > > Similarly it's not *too* hard to trim overlaps; I guess it's really a > question of whether we want to bother :/ I guess then, we can just report it and ignore, pr_warn(FW_BUG, "Found overlapping rmr desc @...., but ignoring...\n" Thanks Shameer > > + } > > + } > > + > > + return 0; > > +} > > + > > +static int __init iort_parse_rmr(struct acpi_iort_node *iort_node) > > +{ > > + struct acpi_iort_node *smmu; > > + struct iort_rmr_entry *e; > > + struct acpi_iort_rmr *rmr; > > + struct acpi_iort_rmr_desc *rmr_desc; > > + u32 map_count = iort_node->mapping_count; > > + u32 sid; > > Nit: extra space. > > > + int i, ret = 0; > > + > > + if (iort_node->type != ACPI_IORT_NODE_RMR) > > + return 0; > > + > > + if (!iort_node->mapping_offset || map_count != 1) { > > Beware that there was some discussion about allowing multiple SIDs to > share an RMR descriptor, since there are potential use-cases which would > otherwise lead to excessive duplication (e.g. an MSI doorbell carveout > in a VM which would effectively apply to all possible PCI RIDs). I think > the conclusion we reached was that disallowing that was fairly > arbitrary, and could possibly be relaxed in future. It looks like the > design of things here could grow to fit that fairly easily though, so I > don't think it's a major concern. > > Robin. > > > + pr_err(FW_BUG "Invalid ID mapping, skipping RMR node %p\n", > > + iort_node); > > + return -EINVAL; > > + } > > + > > + /* Retrieve associated smmu and stream id */ > > + smmu = iort_node_get_id(iort_node, &sid, 0); > > + if (!smmu) { > > + pr_err(FW_BUG "Invalid SMMU reference, skipping RMR > node %p\n", > > + iort_node); > > + return -EINVAL; > > + } > > + > > + /* Retrieve RMR data */ > > + rmr = (struct acpi_iort_rmr *)iort_node->node_data; > > + if (!rmr->rmr_offset || !rmr->rmr_count) { > > + pr_err(FW_BUG "Invalid RMR descriptor array, skipping RMR > node %p\n", > > + iort_node); > > + return -EINVAL; > > + } > > + > > + rmr_desc = ACPI_ADD_PTR(struct acpi_iort_rmr_desc, iort_node, > > + rmr->rmr_offset); > > + > > + ret = iort_rmr_desc_valid(rmr_desc, rmr->rmr_count); > > + if (ret) { > > + pr_err(FW_BUG "Invalid RMR descriptor[%d] for node %p, > skipping...\n", > > + i, iort_node); > > + return ret; > > + } > > + > > + for (i = 0; i < rmr->rmr_count; i++, rmr_desc++) { > > + e = kmalloc(sizeof(*e), GFP_KERNEL); > > + if (!e) > > + return -ENOMEM; > > + > > + e->sid = sid; > > + e->smmu = smmu; > > + e->rmr_desc = rmr_desc; > > + e->flags = rmr->flags; > > + > > + list_add_tail(&e->list, &iort_rmr_list); > > + } > > + > > + return 0; > > +} > > > > static void __init iort_init_platform_devices(void) > > { > > @@ -1689,6 +1788,9 @@ static void __init iort_init_platform_devices(void) > > > > iort_enable_acs(iort_node); > > > > + if (iort_table->revision == 3) > > + iort_parse_rmr(iort_node); > > + > > ops = iort_get_dev_cfg(iort_node); > > if (ops) { > > fwnode = acpi_alloc_fwnode_static(); > >
