Hi Robin,
On 2016-09-12 18:14, Robin Murphy wrote:
With our DMA ops enabled for PCI devices, we should avoid allocating
IOVAs which a host bridge might misinterpret as peer-to-peer DMA and
lead to faults, corruption or other badness. To be safe, punch out holes
for all of the relevant host bridge's windows when initialising a DMA
domain for a PCI device.
CC: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
CC: Inki Dae <inki.dae@xxxxxxxxxxx>
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
I don't know much about PCI and their IOMMU integration, but can't we use
the direct mapping region feature of iommu core for it? There are already
iommu_get_dm_regions(), iommu_put_dm_regions() and
iommu_request_dm_for_dev()
functions for handling them...
---
- Squash in the previous drm/exynos fixup
- If need be, this one can probably wait
---
arch/arm64/mm/dma-mapping.c | 2 +-
drivers/gpu/drm/exynos/exynos_drm_iommu.h | 2 +-
drivers/iommu/dma-iommu.c | 25 ++++++++++++++++++++++++-
include/linux/dma-iommu.h | 3 ++-
4 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index c4284c432ae8..610d8e53011e 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -827,7 +827,7 @@ static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
* then the IOMMU core will have already configured a group for this
* device, and allocated the default domain for that group.
*/
- if (!domain || iommu_dma_init_domain(domain, dma_base, size)) {
+ if (!domain || iommu_dma_init_domain(domain, dma_base, size, dev)) {
pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
dev_name(dev));
return false;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.h b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
index c8de4913fdbe..87f6b5672e11 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
@@ -66,7 +66,7 @@ static inline int __exynos_iommu_create_mapping(struct exynos_drm_private *priv,
if (ret)
goto free_domain;
- ret = iommu_dma_init_domain(domain, start, size);
+ ret = iommu_dma_init_domain(domain, start, size, NULL);
if (ret)
goto put_cookie;
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4329d18080cf..c5ab8667e6f2 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -27,6 +27,7 @@
#include <linux/iova.h>
#include <linux/irq.h>
#include <linux/mm.h>
+#include <linux/pci.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
@@ -103,18 +104,38 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
}
EXPORT_SYMBOL(iommu_put_dma_cookie);
+static void iova_reserve_pci_windows(struct pci_dev *dev,
+ struct iova_domain *iovad)
+{
+ struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+ struct resource_entry *window;
+ unsigned long lo, hi;
+
+ resource_list_for_each_entry(window, &bridge->windows) {
+ if (resource_type(window->res) != IORESOURCE_MEM &&
+ resource_type(window->res) != IORESOURCE_IO)
+ continue;
+
+ lo = iova_pfn(iovad, window->res->start - window->offset);
+ hi = iova_pfn(iovad, window->res->end - window->offset);
+ reserve_iova(iovad, lo, hi);
+ }
+}
+
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
* @base: IOVA at which the mappable address space starts
* @size: Size of IOVA space
+ * @dev: Device the domain is being initialised for
*
* @base and @size should be exact multiples of IOMMU page granularity to
* avoid rounding surprises. If necessary, we reserve the page at address 0
* to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
* any change which could make prior IOVAs invalid will fail.
*/
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size)
+int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
+ u64 size, struct device *dev)
{
struct iova_domain *iovad = cookie_iovad(domain);
unsigned long order, base_pfn, end_pfn;
@@ -152,6 +173,8 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size
iovad->dma_32bit_pfn = end_pfn;
} else {
init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
+ if (dev && dev_is_pci(dev))
+ iova_reserve_pci_windows(to_pci_dev(dev), iovad);
}
return 0;
}
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 5ee806e41b5c..32c589062bd9 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -30,7 +30,8 @@ int iommu_get_dma_cookie(struct iommu_domain *domain);
void iommu_put_dma_cookie(struct iommu_domain *domain);
/* Setup call for arch DMA mapping code */
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size);
+int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
+ u64 size, struct device *dev);
/* General helpers for DMA-API <-> IOMMU-API interaction */
int dma_direction_to_prot(enum dma_data_direction dir, bool coherent);
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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