iommu/dma: Add support for mapping MSIs
When an MSI doorbell is located downstream of an IOMMU, attaching
devices to a DMA ops domain and switching on translation leads to a rude
shock when their attempt to write to the physical address returned by
the irqchip driver faults (or worse, writes into some already-mapped
buffer) and no interrupt is forthcoming.
Address this by adding a hook for relevant irqchip drivers to call from
their compose_msi_msg() callback, to swizzle the physical address with
an appropriatly-mapped IOVA for any device attached to one of our DMA
ops domains.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 00c8a08..4329d18 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -25,10 +25,28 @@
#include <linux/huge_mm.h>
#include <linux/iommu.h>
#include <linux/iova.h>
+#include <linux/irq.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
+struct iommu_dma_msi_page {
+ struct list_head list;
+ dma_addr_t iova;
+ phys_addr_t phys;
+};
+
+struct iommu_dma_cookie {
+ struct iova_domain iovad;
+ struct list_head msi_page_list;
+ spinlock_t msi_lock;
+};
+
+static inline struct iova_domain *cookie_iovad(struct iommu_domain *domain)
+{
+ return &((struct iommu_dma_cookie *)domain->iova_cookie)->iovad;
+}
+
int iommu_dma_init(void)
{
return iova_cache_get();
@@ -43,15 +61,19 @@
*/
int iommu_get_dma_cookie(struct iommu_domain *domain)
{
- struct iova_domain *iovad;
+ struct iommu_dma_cookie *cookie;
if (domain->iova_cookie)
return -EEXIST;
- iovad = kzalloc(sizeof(*iovad), GFP_KERNEL);
- domain->iova_cookie = iovad;
+ cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
+ if (!cookie)
+ return -ENOMEM;
- return iovad ? 0 : -ENOMEM;
+ spin_lock_init(&cookie->msi_lock);
+ INIT_LIST_HEAD(&cookie->msi_page_list);
+ domain->iova_cookie = cookie;
+ return 0;
}
EXPORT_SYMBOL(iommu_get_dma_cookie);
@@ -63,14 +85,20 @@
*/
void iommu_put_dma_cookie(struct iommu_domain *domain)
{
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iommu_dma_msi_page *msi, *tmp;
- if (!iovad)
+ if (!cookie)
return;
- if (iovad->granule)
- put_iova_domain(iovad);
- kfree(iovad);
+ if (cookie->iovad.granule)
+ put_iova_domain(&cookie->iovad);
+
+ list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) {
+ list_del(&msi->list);
+ kfree(msi);
+ }
+ kfree(cookie);
domain->iova_cookie = NULL;
}
EXPORT_SYMBOL(iommu_put_dma_cookie);
@@ -88,7 +116,7 @@
*/
int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size)
{
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
unsigned long order, base_pfn, end_pfn;
if (!iovad)
@@ -155,7 +183,7 @@
static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size,
dma_addr_t dma_limit)
{
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
unsigned long shift = iova_shift(iovad);
unsigned long length = iova_align(iovad, size) >> shift;
@@ -171,7 +199,7 @@
/* The IOVA allocator knows what we mapped, so just unmap whatever that was */
static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr)
{
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
unsigned long shift = iova_shift(iovad);
unsigned long pfn = dma_addr >> shift;
struct iova *iova = find_iova(iovad, pfn);
@@ -294,7 +322,7 @@
void (*flush_page)(struct device *, const void *, phys_addr_t))
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
struct iova *iova;
struct page **pages;
struct sg_table sgt;
@@ -386,7 +414,7 @@
{
dma_addr_t dma_addr;
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
phys_addr_t phys = page_to_phys(page) + offset;
size_t iova_off = iova_offset(iovad, phys);
size_t len = iova_align(iovad, size + iova_off);
@@ -495,7 +523,7 @@
int nents, int prot)
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct iova_domain *iovad = domain->iova_cookie;
+ struct iova_domain *iovad = cookie_iovad(domain);
struct iova *iova;
struct scatterlist *s, *prev = NULL;
dma_addr_t dma_addr;
@@ -587,3 +615,81 @@
{
return dma_addr == DMA_ERROR_CODE;
}
+
+static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
+ phys_addr_t msi_addr, struct iommu_domain *domain)
+{
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iommu_dma_msi_page *msi_page;
+ struct iova_domain *iovad = &cookie->iovad;
+ struct iova *iova;
+ int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+
+ msi_addr &= ~(phys_addr_t)iova_mask(iovad);
+ list_for_each_entry(msi_page, &cookie->msi_page_list, list)
+ if (msi_page->phys == msi_addr)
+ return msi_page;
+
+ msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC);
+ 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))
+ goto out_free_iova;
+
+ INIT_LIST_HEAD(&msi_page->list);
+ list_add(&msi_page->list, &cookie->msi_page_list);
+ return msi_page;
+
+out_free_iova:
+ __free_iova(iovad, iova);
+out_free_page:
+ kfree(msi_page);
+ return NULL;
+}
+
+void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
+{
+ struct device *dev = msi_desc_to_dev(irq_get_msi_desc(irq));
+ struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+ struct iommu_dma_cookie *cookie;
+ struct iommu_dma_msi_page *msi_page;
+ phys_addr_t msi_addr = (u64)msg->address_hi << 32 | msg->address_lo;
+ unsigned long flags;
+
+ if (!domain || !domain->iova_cookie)
+ return;
+
+ cookie = domain->iova_cookie;
+
+ /*
+ * We disable IRQs to rule out a possible inversion against
+ * irq_desc_lock if, say, someone tries to retarget the affinity
+ * of an MSI from within an IPI handler.
+ */
+ spin_lock_irqsave(&cookie->msi_lock, flags);
+ msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
+ spin_unlock_irqrestore(&cookie->msi_lock, flags);
+
+ if (WARN_ON(!msi_page)) {
+ /*
+ * We're called from a void callback, so the best we can do is
+ * 'fail' by filling the message with obviously bogus values.
+ * Since we got this far due to an IOMMU being present, it's
+ * not like the existing address would have worked anyway...
+ */
+ msg->address_hi = ~0U;
+ msg->address_lo = ~0U;
+ msg->data = ~0U;
+ } else {
+ msg->address_hi = upper_32_bits(msi_page->iova);
+ msg->address_lo &= iova_mask(&cookie->iovad);
+ msg->address_lo += lower_32_bits(msi_page->iova);
+ }
+}