[PATCH v2 3/4] iommu/dma: Handle IOMMU API reserved regions
Robin Murphy
robin.murphy at arm.com
Thu Mar 16 10:00:18 PDT 2017
Now that it's simple to discover the necessary reservations for a given
device/IOMMU combination, let's wire up the appropriate handling. Basic
reserved regions and direct-mapped regions we simply have to carve out
of IOVA space (the IOMMU core having already mapped the latter before
attaching the device). For hardware MSI regions, we also pre-populate
the cookie with matching msi_pages. That way, irqchip drivers which
normally assume MSIs to require mapping at the IOMMU can keep working
without having to special-case their iommu_dma_map_msi_msg() hook, or
indeed be aware at all of quirks preventing the IOMMU from translating
certain addresses.
Reviewed-by: Eric Auger <eric.auger at redhat.com>
Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
Notes:
v2:
- Make the IOVA alignment logic safer [Eric]
- Don't duplicate direct region mapping [Eric]
- Don't wait for the subsequent patch to start using the return value [Eric]
- Fix the sneaky off-by-one for pfn_hi
- Minor cosmetic tweaks
drivers/iommu/dma-iommu.c | 76 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 69 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 1e0983488a8d..5787f919f4ec 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -184,6 +184,66 @@ static void iova_reserve_pci_windows(struct pci_dev *dev,
}
}
+static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,
+ phys_addr_t start, phys_addr_t end)
+{
+ struct iova_domain *iovad = &cookie->iovad;
+ struct iommu_dma_msi_page *msi_page;
+ int i, num_pages;
+
+ start -= iova_offset(iovad, start);
+ num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);
+
+ msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);
+ if (!msi_page)
+ return -ENOMEM;
+
+ for (i = 0; i < num_pages; i++) {
+ msi_page[i].phys = start;
+ msi_page[i].iova = start;
+ INIT_LIST_HEAD(&msi_page[i].list);
+ list_add(&msi_page[i].list, &cookie->msi_page_list);
+ start += iovad->granule;
+ }
+
+ return 0;
+}
+
+static int iova_reserve_iommu_regions(struct device *dev,
+ struct iommu_domain *domain)
+{
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iova_domain *iovad = &cookie->iovad;
+ struct iommu_resv_region *region;
+ LIST_HEAD(resv_regions);
+ int ret = 0;
+
+ if (dev_is_pci(dev))
+ iova_reserve_pci_windows(to_pci_dev(dev), iovad);
+
+ iommu_get_resv_regions(dev, &resv_regions);
+ list_for_each_entry(region, &resv_regions, list) {
+ unsigned long lo, hi;
+
+ /* We ARE the software that manages these! */
+ if (region->type == IOMMU_RESV_SW_MSI)
+ continue;
+
+ lo = iova_pfn(iovad, region->start);
+ hi = iova_pfn(iovad, region->start + region->length - 1);
+ reserve_iova(iovad, lo, hi);
+
+ if (region->type == IOMMU_RESV_MSI)
+ ret = cookie_init_hw_msi_region(cookie, region->start,
+ region->start + region->length);
+ if (ret)
+ break;
+ }
+ iommu_put_resv_regions(dev, &resv_regions);
+
+ return ret;
+}
+
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -202,7 +262,6 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
unsigned long order, base_pfn, end_pfn;
- bool pci = dev && dev_is_pci(dev);
if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
return -EINVAL;
@@ -232,7 +291,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
* leave the cache limit at the top of their range to save an rb_last()
* traversal on every allocation.
*/
- if (pci)
+ if (dev && dev_is_pci(dev))
end_pfn &= DMA_BIT_MASK(32) >> order;
/* start_pfn is always nonzero for an already-initialised domain */
@@ -247,12 +306,15 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
* area cache limit down for the benefit of the smaller one.
*/
iovad->dma_32bit_pfn = min(end_pfn, iovad->dma_32bit_pfn);
- } else {
- init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
- if (pci)
- iova_reserve_pci_windows(to_pci_dev(dev), iovad);
+
+ return 0;
}
- return 0;
+
+ init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
+ if (!dev)
+ return 0;
+
+ return iova_reserve_iommu_regions(dev, domain);
}
EXPORT_SYMBOL(iommu_dma_init_domain);
--
2.11.0.dirty
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