Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
v1 -> v2:
- unmap stage2 on put()
---
drivers/iommu/dma-iommu.c | 97 +++++++++++++++++++++++++++++++++++++--
include/linux/dma-iommu.h | 11 +++++
2 files changed, 105 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 511ff9a1d6d9..53444c3e8f2f 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -37,12 +37,14 @@
struct iommu_dma_msi_page {
struct list_head list;
dma_addr_t iova;
+ dma_addr_t ipa;
phys_addr_t phys;
};
enum iommu_dma_cookie_type {
IOMMU_DMA_IOVA_COOKIE,
IOMMU_DMA_MSI_COOKIE,
+ IOMMU_DMA_NESTED_MSI_COOKIE,
};
struct iommu_dma_cookie {
@@ -109,14 +111,17 @@ EXPORT_SYMBOL(iommu_get_dma_cookie);
*
* 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
+ * this to initialise their own domain appropriately. Users may 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.
+ * used by the devices attached to @domain. The other way round is to provide
+ * usable iova pages through the iommu_dma_bind_doorbell API (nested stages
+ * use case)
*/
int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
{
struct iommu_dma_cookie *cookie;
+ int nesting, ret;
if (domain->type != IOMMU_DOMAIN_UNMANAGED)
return -EINVAL;
@@ -124,7 +129,12 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
if (domain->iova_cookie)
return -EEXIST;
- cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE);
+ ret = iommu_domain_get_attr(domain, DOMAIN_ATTR_NESTING, &nesting);
+ if (!ret && nesting)
+ cookie = cookie_alloc(IOMMU_DMA_NESTED_MSI_COOKIE);
+ else
+ cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE);
+
if (!cookie)
return -ENOMEM;
@@ -145,6 +155,7 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi, *tmp;
+ bool s2_unmap = false;
if (!cookie)
return;
@@ -152,7 +163,15 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
if (cookie->type == IOMMU_DMA_IOVA_COOKIE && cookie->iovad.granule)
put_iova_domain(&cookie->iovad);
+ if (cookie->type == IOMMU_DMA_NESTED_MSI_COOKIE)
+ s2_unmap = true;
+
list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) {
+ if (s2_unmap && msi->phys) {
+ size_t size = cookie_msi_granule(cookie);
+
+ WARN_ON(iommu_unmap(domain, msi->ipa, size) != size);
+ }
list_del(&msi->list);
kfree(msi);
}
@@ -161,6 +180,50 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
}
EXPORT_SYMBOL(iommu_put_dma_cookie);
+/**
+ * iommu_dma_bind_doorbell - Allows to provide a usable IOVA page
+ * @domain: domain handle
+ * @binding: IOVA/IPA binding
+ *
+ * In nested stage use case, the user can provide IOVA/IPA bindings
+ * corresponding to a guest MSI stage 1 mapping. When the host needs
+ * to map its own MSI doorbells, it can use the IPA as stage 2 input
+ * and map it onto the physical MSI doorbell.
+ */
+int iommu_dma_bind_doorbell(struct iommu_domain *domain,
+ struct iommu_guest_msi_binding *binding)
+{
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iommu_dma_msi_page *msi;
+ dma_addr_t ipa, iova;
+ size_t size;
+
+ if (!cookie)
+ return -EINVAL;
+
+ if (cookie->type != IOMMU_DMA_NESTED_MSI_COOKIE)
+ return -EINVAL;
+
+ size = 1 << binding->granule;
+ iova = binding->iova & ~(phys_addr_t)(size - 1);
+ ipa = binding->gpa & ~(phys_addr_t)(size - 1);
+
+ list_for_each_entry(msi, &cookie->msi_page_list, list) {
+ if (msi->iova == iova)
+ return 0; /* this page is already registered */
+ }
+
+ msi = kzalloc(sizeof(*msi), GFP_KERNEL);
+ if (!msi)
+ return -ENOMEM;
+
+ msi->iova = iova;
+ msi->ipa = ipa;
+ list_add(&msi->list, &cookie->msi_page_list);
+ return 0;
+}
+EXPORT_SYMBOL(iommu_dma_bind_doorbell);
+
/**
* iommu_dma_get_resv_regions - Reserved region driver helper
* @dev: Device from iommu_get_resv_regions()
@@ -846,6 +909,34 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
if (msi_page->phys == msi_addr)
return msi_page;
+ /*
+ * In nested stage mode, we do not allocate an MSI page in
+ * a range provided by the user. Instead, IOVA/IPA bindings are
+ * individually provided. We reuse thise IOVAs to build the
+ * IOVA -> IPA -> MSI PA nested stage mapping.
+ */
+ if (cookie->type == IOMMU_DMA_NESTED_MSI_COOKIE) {
+ list_for_each_entry(msi_page, &cookie->msi_page_list, list)
+ if (!msi_page->phys) { /* this binding is free to use */
+ dma_addr_t ipa = msi_page->ipa;
+ int ret;
+
+ msi_page->phys = msi_addr;
+
+ /* do the stage 2 mapping */
+ ret = iommu_map(domain, ipa, msi_addr, size,
+ IOMMU_MMIO | IOMMU_WRITE);
+ if (ret) {
+ pr_warn("MSI S2 mapping failed (%d)\n",
+ ret);
+ return NULL;
+ }
+ return msi_page;
+ }
+ pr_warn("%s no MSI binding found\n", __func__);
+ return NULL;
+ }
+
msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC);
if (!msi_page)
return NULL;
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index e8ca5e654277..324745eef644 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -24,6 +24,7 @@
#include <linux/dma-mapping.h>
#include <linux/iommu.h>
#include <linux/msi.h>
+#include <uapi/linux/iommu.h>
int iommu_dma_init(void);
@@ -74,12 +75,15 @@ int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
/* The DMA API isn't _quite_ the whole story, though... */
void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);
void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
+int iommu_dma_bind_doorbell(struct iommu_domain *domain,
+ struct iommu_guest_msi_binding *binding);
#else
struct iommu_domain;
struct msi_msg;
struct device;
+struct iommu_guest_msi_binding;
static inline int iommu_dma_init(void)
{
@@ -104,6 +108,13 @@ static inline void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
{
}
+static inline int
+iommu_dma_bind_doorbell(struct iommu_domain *domain,
+ struct iommu_guest_msi_binding *binding)
+{
+ return -ENODEV;
+}
+
static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
{
}
