Currently, the IOVA and its mapping (to physical doorbell address) is done
by the dma-iommu via the iommu_cookie in the struct msi_desc, which is the
structure used by three parties: genirq, irqchip and dma-iommu.
However, when dealing with a nested translation on ARM64, the MSI doorbell
address is behind the SMMU (IOMMU on ARM64), thus HW needs to be programed
with the stage-1 IOVA, i.e. guest-level IOVA, rather than asking dma-iommu
to allocate one.
To support a guest-programmable pathway, first we need to make sure struct
msi_desc will allow a preset IOVA v.s. using iommu_cookie. Add an msi_iova
to the structure and init its value to PHYS_ADDR_MAX. And provide a helper
for drivers to get the msi_iova out of an msi_desc object.
A following patch will change msi_setup_msi_descs and msix_setup_msi_descs
to call msi_domain_insert_msi_desc and finish the actual value forwarding.
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
include/linux/msi.h | 11 +++++++++++
kernel/irq/msi.c | 6 ++++++
2 files changed, 17 insertions(+)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index b10093c4d00e..873094743065 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -185,6 +185,7 @@ struct msi_desc {
struct irq_affinity_desc *affinity;
#ifdef CONFIG_IRQ_MSI_IOMMU
const void *iommu_cookie;
+ dma_addr_t msi_iova;
#endif
#ifdef CONFIG_SYSFS
struct device_attribute *sysfs_attrs;
@@ -296,6 +297,11 @@ static inline void msi_desc_set_iommu_cookie(struct msi_desc *desc,
{
desc->iommu_cookie = iommu_cookie;
}
+
+static inline dma_addr_t msi_desc_get_iova(struct msi_desc *desc)
+{
+ return desc->msi_iova;
+}
#else
static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
{
@@ -306,6 +312,11 @@ static inline void msi_desc_set_iommu_cookie(struct msi_desc *desc,
const void *iommu_cookie)
{
}
+
+static inline dma_addr_t msi_desc_get_iova(struct msi_desc *desc)
+{
+ return PHYS_ADDR_MAX;
+}
#endif
int msi_domain_insert_msi_desc(struct device *dev, unsigned int domid,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 3a24d6b5f559..f3159ec0f036 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -81,6 +81,9 @@ static struct msi_desc *msi_alloc_desc(struct device *dev, int nvec,
desc->dev = dev;
desc->nvec_used = nvec;
+#ifdef CONFIG_IRQ_MSI_IOMMU
+ desc->msi_iova = PHYS_ADDR_MAX;
+#endif
if (affinity) {
desc->affinity = kmemdup_array(affinity, nvec, sizeof(*desc->affinity), GFP_KERNEL);
if (!desc->affinity) {
@@ -158,6 +161,9 @@ int msi_domain_insert_msi_desc(struct device *dev, unsigned int domid,
/* Copy type specific data to the new descriptor. */
desc->pci = init_desc->pci;
+#ifdef CONFIG_IRQ_MSI_IOMMU
+ desc->msi_iova = init_desc->msi_iova;
+#endif
return msi_insert_desc(dev, desc, domid, init_desc->msi_index);
}
--
2.43.0
