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authorRobin Murphy <robin.murphy@arm.com>2017-01-19 23:57:46 +0300
committerWill Deacon <will.deacon@arm.com>2017-01-23 14:48:16 +0300
commitfdbe574eb69312a7fbe09674d69c01b80e4ed9dc (patch)
tree6c4cc7dd1fe4eb0188343281fb83572383ddb8dd /drivers/iommu
parenta121103c922847ba5010819a3f250f1f7fc84ab8 (diff)
downloadlinux-fdbe574eb69312a7fbe09674d69c01b80e4ed9dc.tar.xz
iommu/dma: Allow MSI-only cookies
IOMMU domain users such as VFIO face a similar problem to DMA API ops with regard to mapping MSI messages in systems where the MSI write is subject to IOMMU translation. With the relevant infrastructure now in place for managed DMA domains, it's actually really simple for other users to piggyback off that and reap the benefits without giving up their own IOVA management, and without having to reinvent their own wheel in the MSI layer. Allow such users to opt into automatic MSI remapping by dedicating a region of their IOVA space to a managed cookie, and extend the mapping routine to implement a trivial linear allocator in such cases, to avoid the needless overhead of a full-blown IOVA domain. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Tested-by: Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com> Tested-by: Bharat Bhushan <bharat.bhushan@nxp.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/dma-iommu.c119
1 files changed, 96 insertions, 23 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 2db0d641cf45..de41ead6542a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -37,15 +37,50 @@ struct iommu_dma_msi_page {
phys_addr_t phys;
};
+enum iommu_dma_cookie_type {
+ IOMMU_DMA_IOVA_COOKIE,
+ IOMMU_DMA_MSI_COOKIE,
+};
+
struct iommu_dma_cookie {
- struct iova_domain iovad;
- struct list_head msi_page_list;
- spinlock_t msi_lock;
+ enum iommu_dma_cookie_type type;
+ union {
+ /* Full allocator for IOMMU_DMA_IOVA_COOKIE */
+ struct iova_domain iovad;
+ /* Trivial linear page allocator for IOMMU_DMA_MSI_COOKIE */
+ dma_addr_t msi_iova;
+ };
+ struct list_head msi_page_list;
+ spinlock_t msi_lock;
};
+static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
+{
+ if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
+ return cookie->iovad.granule;
+ return PAGE_SIZE;
+}
+
static inline struct iova_domain *cookie_iovad(struct iommu_domain *domain)
{
- return &((struct iommu_dma_cookie *)domain->iova_cookie)->iovad;
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+
+ if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
+ return &cookie->iovad;
+ return NULL;
+}
+
+static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
+{
+ struct iommu_dma_cookie *cookie;
+
+ cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
+ if (cookie) {
+ spin_lock_init(&cookie->msi_lock);
+ INIT_LIST_HEAD(&cookie->msi_page_list);
+ cookie->type = type;
+ }
+ return cookie;
}
int iommu_dma_init(void)
@@ -62,25 +97,53 @@ int iommu_dma_init(void)
*/
int iommu_get_dma_cookie(struct iommu_domain *domain)
{
+ if (domain->iova_cookie)
+ return -EEXIST;
+
+ domain->iova_cookie = cookie_alloc(IOMMU_DMA_IOVA_COOKIE);
+ if (!domain->iova_cookie)
+ return -ENOMEM;
+
+ return 0;
+}
+EXPORT_SYMBOL(iommu_get_dma_cookie);
+
+/**
+ * iommu_get_msi_cookie - Acquire just MSI remapping resources
+ * @domain: IOMMU domain to prepare
+ * @base: Start address of IOVA region for MSI mappings
+ *
+ * Users who manage their own IOVA allocation and do not want DMA API support,
+ * but would still like to take advantage of automatic MSI remapping, can use
+ * this to initialise their own domain appropriately. Users should reserve a
+ * contiguous IOVA region, starting at @base, large enough to accommodate the
+ * number of PAGE_SIZE mappings necessary to cover every MSI doorbell address
+ * used by the devices attached to @domain.
+ */
+int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
+{
struct iommu_dma_cookie *cookie;
+ if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+ return -EINVAL;
+
if (domain->iova_cookie)
return -EEXIST;
- cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
+ cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE);
if (!cookie)
return -ENOMEM;
- spin_lock_init(&cookie->msi_lock);
- INIT_LIST_HEAD(&cookie->msi_page_list);
+ cookie->msi_iova = base;
domain->iova_cookie = cookie;
return 0;
}
-EXPORT_SYMBOL(iommu_get_dma_cookie);
+EXPORT_SYMBOL(iommu_get_msi_cookie);
/**
* iommu_put_dma_cookie - Release a domain's DMA mapping resources
- * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
+ * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() or
+ * iommu_get_msi_cookie()
*
* IOMMU drivers should normally call this from their domain_free callback.
*/
@@ -92,7 +155,7 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
if (!cookie)
return;
- if (cookie->iovad.granule)
+ if (cookie->type == IOMMU_DMA_IOVA_COOKIE && cookie->iovad.granule)
put_iova_domain(&cookie->iovad);
list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) {
@@ -137,11 +200,12 @@ static void iova_reserve_pci_windows(struct pci_dev *dev,
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);
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iova_domain *iovad = &cookie->iovad;
unsigned long order, base_pfn, end_pfn;
- if (!iovad)
- return -ENODEV;
+ if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
+ return -EINVAL;
/* Use the smallest supported page size for IOVA granularity */
order = __ffs(domain->pgsize_bitmap);
@@ -662,11 +726,12 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi_page;
- struct iova_domain *iovad = &cookie->iovad;
+ struct iova_domain *iovad = cookie_iovad(domain);
struct iova *iova;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+ size_t size = cookie_msi_granule(cookie);
- msi_addr &= ~(phys_addr_t)iova_mask(iovad);
+ msi_addr &= ~(phys_addr_t)(size - 1);
list_for_each_entry(msi_page, &cookie->msi_page_list, list)
if (msi_page->phys == msi_addr)
return msi_page;
@@ -675,13 +740,18 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
if (!msi_page)
return NULL;
- iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev));
- if (!iova)
- goto out_free_page;
-
msi_page->phys = msi_addr;
- msi_page->iova = iova_dma_addr(iovad, iova);
- if (iommu_map(domain, msi_page->iova, msi_addr, iovad->granule, prot))
+ if (iovad) {
+ iova = __alloc_iova(domain, size, dma_get_mask(dev));
+ if (!iova)
+ goto out_free_page;
+ msi_page->iova = iova_dma_addr(iovad, iova);
+ } else {
+ msi_page->iova = cookie->msi_iova;
+ cookie->msi_iova += size;
+ }
+
+ if (iommu_map(domain, msi_page->iova, msi_addr, size, prot))
goto out_free_iova;
INIT_LIST_HEAD(&msi_page->list);
@@ -689,7 +759,10 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
return msi_page;
out_free_iova:
- __free_iova(iovad, iova);
+ if (iovad)
+ __free_iova(iovad, iova);
+ else
+ cookie->msi_iova -= size;
out_free_page:
kfree(msi_page);
return NULL;
@@ -730,7 +803,7 @@ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
msg->data = ~0U;
} else {
msg->address_hi = upper_32_bits(msi_page->iova);
- msg->address_lo &= iova_mask(&cookie->iovad);
+ msg->address_lo &= cookie_msi_granule(cookie) - 1;
msg->address_lo += lower_32_bits(msi_page->iova);
}
}