The user is allowed to [un]register a reserved IOVA range by using the
DMA MAP API and setting the new flag: VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA.
It provides the base address and the size. This region is stored in the
vfio_dma rb tree. At that point the iova range is not mapped to any target
address yet. The host kernel will use those iova when needed, typically
when the VFIO-PCI device allocates its MSIs.
This patch also handles the destruction of the reserved binding RB-tree and
domain's iova_domains.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>
---
v3 -> v4:
- use iommu_alloc/free_reserved_iova_domain exported by dma-reserved-iommu
- protect vfio_register_reserved_iova_range implementation with
CONFIG_IOMMU_DMA_RESERVED
- handle unregistration by user-space and on vfio_iommu_type1 release
v1 -> v2:
- set returned value according to alloc_reserved_iova_domain result
- free the iova domains in case any error occurs
RFC v1 -> v1:
- takes into account Alex comments, based on
[RFC PATCH 1/6] vfio: Add interface for add/del reserved iova region:
- use the existing dma map/unmap ioctl interface with a flag to register
a reserved IOVA range. A single reserved iova region is allowed.
---
drivers/vfio/vfio_iommu_type1.c | 141 +++++++++++++++++++++++++++++++++++++++-
include/uapi/linux/vfio.h | 12 +++-
2 files changed, 150 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 692e9a2..4e01ebe 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -36,6 +36,7 @@
#include <linux/uaccess.h>
#include <linux/vfio.h>
#include <linux/workqueue.h>
+#include <linux/dma-reserved-iommu.h>
#define DRIVER_VERSION "0.2"
#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@xxxxxxxxxx>"
@@ -403,10 +404,22 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
vfio_lock_acct(-unlocked);
}
+static void vfio_unmap_reserved(struct vfio_iommu *iommu)
+{
+#ifdef CONFIG_IOMMU_DMA_RESERVED
+ struct vfio_domain *d;
+
+ list_for_each_entry(d, &iommu->domain_list, next)
+ iommu_unmap_reserved(d->domain);
+#endif
+}
+
static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
{
if (likely(dma->type != VFIO_IOVA_RESERVED))
vfio_unmap_unpin(iommu, dma);
+ else
+ vfio_unmap_reserved(iommu);
vfio_unlink_dma(iommu, dma);
kfree(dma);
}
@@ -489,7 +502,8 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
*/
if (iommu->v2) {
dma = vfio_find_dma(iommu, unmap->iova, 0);
- if (dma && dma->iova != unmap->iova) {
+ if (dma && (dma->iova != unmap->iova ||
+ (dma->type == VFIO_IOVA_RESERVED))) {
ret = -EINVAL;
goto unlock;
}
@@ -501,6 +515,10 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
}
while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
+ if (dma->type == VFIO_IOVA_RESERVED) {
+ ret = -EINVAL;
+ goto unlock;
+ }
if (!iommu->v2 && unmap->iova > dma->iova)
break;
unmapped += dma->size;
@@ -650,6 +668,114 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
return ret;
}
+static int vfio_register_reserved_iova_range(struct vfio_iommu *iommu,
+ struct vfio_iommu_type1_dma_map *map)
+{
+#ifdef CONFIG_IOMMU_DMA_RESERVED
+ dma_addr_t iova = map->iova;
+ size_t size = map->size;
+ uint64_t mask;
+ struct vfio_dma *dma;
+ int ret = 0;
+ struct vfio_domain *d;
+ unsigned long order;
+
+ /* Verify that none of our __u64 fields overflow */
+ if (map->size != size || map->iova != iova)
+ return -EINVAL;
+
+ order = __ffs(vfio_pgsize_bitmap(iommu));
+ mask = ((uint64_t)1 << order) - 1;
+
+ WARN_ON(mask & PAGE_MASK);
+
+ if (!size || (size | iova) & mask)
+ return -EINVAL;
+
+ /* Don't allow IOVA address wrap */
+ if (iova + size - 1 < iova)
+ return -EINVAL;
+
+ mutex_lock(&iommu->lock);
+
+ if (vfio_find_dma(iommu, iova, size)) {
+ ret = -EEXIST;
+ goto out;
+ }
+
+ dma = kzalloc(sizeof(*dma), GFP_KERNEL);
+ if (!dma) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ dma->iova = iova;
+ dma->size = size;
+ dma->type = VFIO_IOVA_RESERVED;
+
+ list_for_each_entry(d, &iommu->domain_list, next)
+ ret |= iommu_alloc_reserved_iova_domain(d->domain, iova,
+ size, order);
+
+ if (ret) {
+ list_for_each_entry(d, &iommu->domain_list, next)
+ iommu_free_reserved_iova_domain(d->domain);
+ goto out;
+ }
+
+ vfio_link_dma(iommu, dma);
+
+out:
+ mutex_unlock(&iommu->lock);
+ return ret;
+#else /* CONFIG_IOMMU_DMA_RESERVED */
+ return -ENODEV;
+#endif
+}
+
+static void vfio_unregister_reserved_iova_range(struct vfio_iommu *iommu,
+ struct vfio_iommu_type1_dma_unmap *unmap)
+{
+#ifdef CONFIG_IOMMU_DMA_RESERVED
+ dma_addr_t iova = unmap->iova;
+ struct vfio_dma *dma;
+ size_t size = unmap->size;
+ uint64_t mask;
+ unsigned long order;
+
+ /* Verify that none of our __u64 fields overflow */
+ if (unmap->size != size || unmap->iova != iova)
+ return;
+
+ order = __ffs(vfio_pgsize_bitmap(iommu));
+ mask = ((uint64_t)1 << order) - 1;
+
+ WARN_ON(mask & PAGE_MASK);
+
+ if (!size || (size | iova) & mask)
+ return;
+
+ /* Don't allow IOVA address wrap */
+ if (iova + size - 1 < iova)
+ return;
+
+ mutex_lock(&iommu->lock);
+
+ dma = vfio_find_dma(iommu, iova, size);
+
+ if (!dma || (dma->type != VFIO_IOVA_RESERVED)) {
+ unmap->size = 0;
+ goto out;
+ }
+
+ unmap->size = dma->size;
+ vfio_remove_dma(iommu, dma);
+
+out:
+ mutex_unlock(&iommu->lock);
+#endif
+}
+
static int vfio_bus_type(struct device *dev, void *data)
{
struct bus_type **bus = data;
@@ -946,6 +1072,7 @@ static void vfio_iommu_type1_release(void *iommu_data)
struct vfio_group *group, *group_tmp;
vfio_iommu_unmap_unpin_all(iommu);
+ vfio_unmap_reserved(iommu);
list_for_each_entry_safe(domain, domain_tmp,
&iommu->domain_list, next) {
@@ -1019,7 +1146,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
} else if (cmd == VFIO_IOMMU_MAP_DMA) {
struct vfio_iommu_type1_dma_map map;
uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
- VFIO_DMA_MAP_FLAG_WRITE;
+ VFIO_DMA_MAP_FLAG_WRITE |
+ VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA;
minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
@@ -1029,6 +1157,9 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
if (map.argsz < minsz || map.flags & ~mask)
return -EINVAL;
+ if (map.flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA)
+ return vfio_register_reserved_iova_range(iommu, &map);
+
return vfio_dma_do_map(iommu, &map);
} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
@@ -1043,10 +1174,16 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
if (unmap.argsz < minsz || unmap.flags)
return -EINVAL;
+ if (unmap.flags & VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA) {
+ vfio_unregister_reserved_iova_range(iommu, &unmap);
+ goto out;
+ }
+
ret = vfio_dma_do_unmap(iommu, &unmap);
if (ret)
return ret;
+out:
return copy_to_user((void __user *)arg, &unmap, minsz);
}
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 7d7a4c6..d5a48e7 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -410,12 +410,21 @@ struct vfio_iommu_type1_info {
*
* Map process virtual addresses to IO virtual addresses using the
* provided struct vfio_dma_map. Caller sets argsz. READ &/ WRITE required.
+ *
+ * In case MSI_RESERVED_IOVA flag is set, the API only aims at registering an
+ * IOVA region which will be used on some platforms to map the host MSI frame.
+ * in that specific case, vaddr and prot are ignored. The requirement for
+ * provisioning such IOVA range can be checked by calling VFIO_IOMMU_GET_INFO
+ * with the VFIO_IOMMU_INFO_REQUIRE_MSI_MAP attribute. A single
+ * MSI_RESERVED_IOVA region can be registered
*/
struct vfio_iommu_type1_dma_map {
__u32 argsz;
__u32 flags;
#define VFIO_DMA_MAP_FLAG_READ (1 << 0) /* readable from device */
#define VFIO_DMA_MAP_FLAG_WRITE (1 << 1) /* writable from device */
+/* reserved iova for MSI vectors*/
+#define VFIO_DMA_MAP_FLAG_MSI_RESERVED_IOVA (1 << 2)
__u64 vaddr; /* Process virtual address */
__u64 iova; /* IO virtual address */
__u64 size; /* Size of mapping (bytes) */
@@ -431,7 +440,8 @@ struct vfio_iommu_type1_dma_map {
* Caller sets argsz. The actual unmapped size is returned in the size
* field. No guarantee is made to the user that arbitrary unmaps of iova
* or size different from those used in the original mapping call will
- * succeed.
+ * succeed. A Reserved DMA region must be unmapped with MSI_RESERVED_IOVA
+ * flag set.
*/
struct vfio_iommu_type1_dma_unmap {
__u32 argsz;
--
1.9.1
--
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