From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
To add a workaround code for ipmmu-vmsa driver, this patch adds
a new geometry "force_reset_when_empty" not to reuse iova space.
When all pfns happen to get unmapped then ask the IOMMU driver to
flush the state followed by starting from an empty iova space.
Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 42 +++++++++++++++++++++++++++++++++++++-----
drivers/iommu/iova.c | 9 +++++++++
include/linux/iommu.h | 2 ++
include/linux/iova.h | 1 +
4 files changed, 49 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index a0b8c0f..d0fa0b1 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -42,6 +42,7 @@ struct iommu_dma_cookie {
struct iova_domain iovad;
struct list_head msi_page_list;
spinlock_t msi_lock;
+ spinlock_t reset_lock;
};
static inline struct iova_domain *cookie_iovad(struct iommu_domain *domain)
@@ -74,6 +75,7 @@ int iommu_get_dma_cookie(struct iommu_domain *domain)
spin_lock_init(&cookie->msi_lock);
INIT_LIST_HEAD(&cookie->msi_page_list);
+ spin_lock_init(&cookie->reset_lock);
domain->iova_cookie = cookie;
return 0;
}
@@ -208,9 +210,11 @@ int dma_direction_to_prot(enum dma_data_direction dir, bool coherent)
static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
dma_addr_t dma_limit)
{
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = cookie_iovad(domain);
unsigned long shift = iova_shift(iovad);
unsigned long length = iova_align(iovad, size) >> shift;
+ unsigned long flags;
struct iova *iova;
if (domain->geometry.force_aperture)
@@ -219,9 +223,19 @@ static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
* Enforce size-alignment to be safe - there could perhaps be an
* attribute to control this per-device, or at least per-domain...
*/
- iova = alloc_iova(iovad, length, dma_limit >> shift, true);
- if (iova)
- atomic_add(iova_size(iova), &domain->iova_pfns_mapped);
+ if (domain->geometry.force_reset_when_empty) {
+ spin_lock_irqsave(&cookie->reset_lock, flags);
+
+ iova = alloc_iova(iovad, length, dma_limit >> shift, true);
+ if (iova)
+ atomic_add(iova_size(iova), &domain->iova_pfns_mapped);
+
+ spin_unlock_irqrestore(&cookie->reset_lock, flags);
+ } else {
+ iova = alloc_iova(iovad, length, dma_limit >> shift, true);
+ if (iova)
+ atomic_add(iova_size(iova), &domain->iova_pfns_mapped);
+ }
return iova;
}
@@ -229,10 +243,28 @@ static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
void
__free_iova_domain(struct iommu_domain *domain, struct iova *iova)
{
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = cookie_iovad(domain);
+ unsigned long flags;
- atomic_sub(iova_size(iova), &domain->iova_pfns_mapped);
- __free_iova(iovad, iova);
+ /* In case force_reset_when_empty is set, do not reuse iova space
+ * but instead simply keep on expanding seemingly forever.
+ * When all pfns happen to get unmapped then ask the IOMMU driver to
+ * flush the state followed by starting from an empty iova space.
+ */
+ if (domain->geometry.force_reset_when_empty) {
+ spin_lock_irqsave(&cookie->reset_lock, flags);
+ if (atomic_sub_return(iova_size(iova),
+ &domain->iova_pfns_mapped) == 0) {
+ reset_iova_domain(iovad);
+ if (domain->ops->domain_reset)
+ domain->ops->domain_reset(domain);
+ }
+ spin_unlock_irqrestore(&cookie->reset_lock, flags);
+ } else {
+ atomic_sub(iova_size(iova), &domain->iova_pfns_mapped);
+ __free_iova(iovad, iova);
+ }
}
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 866ad65..50aaa46 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -464,6 +464,7 @@ void put_iova_domain(struct iova_domain *iovad)
while (node) {
struct iova *iova = rb_entry(node, struct iova, node);
+ __cached_rbnode_delete_update(iovad, iova);
rb_erase(node, &iovad->rbroot);
free_iova_mem(iova);
node = rb_first(&iovad->rbroot);
@@ -472,6 +473,14 @@ void put_iova_domain(struct iova_domain *iovad)
}
EXPORT_SYMBOL_GPL(put_iova_domain);
+void
+reset_iova_domain(struct iova_domain *iovad)
+{
+ put_iova_domain(iovad);
+ init_iova_rcaches(iovad);
+}
+EXPORT_SYMBOL_GPL(reset_iova_domain);
+
static int
__is_range_overlap(struct rb_node *node,
unsigned long pfn_lo, unsigned long pfn_hi)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 91d0159..bd9ba1b 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -51,6 +51,7 @@ struct iommu_domain_geometry {
dma_addr_t aperture_start; /* First address that can be mapped */
dma_addr_t aperture_end; /* Last address that can be mapped */
bool force_aperture; /* DMA only allowed in mappable range? */
+ bool force_reset_when_empty;
};
/* Domain feature flags */
@@ -168,6 +169,7 @@ struct iommu_ops {
/* Domain allocation and freeing by the iommu driver */
struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
void (*domain_free)(struct iommu_domain *);
+ void (*domain_reset)(struct iommu_domain *);
int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
diff --git a/include/linux/iova.h b/include/linux/iova.h
index f27bb2c..31c8496 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -103,6 +103,7 @@ void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
unsigned long start_pfn, unsigned long pfn_32bit);
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
void put_iova_domain(struct iova_domain *iovad);
+void reset_iova_domain(struct iova_domain *iovad);
struct iova *split_and_remove_iova(struct iova_domain *iovad,
struct iova *iova, unsigned long pfn_lo, unsigned long pfn_hi);
void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad);
--
1.9.1
