genirq/msi: Refactor iommu_dma_compose_msi_msg()

The two-step process to translate the MSI address involves two functions,
iommu_dma_prepare_msi() and iommu_dma_compose_msi_msg().

Previously iommu_dma_compose_msi_msg() needed to be in the iommu layer as
it had to dereference the opaque cookie pointer. Now, the previous patch
changed the cookie pointer into an integer so there is no longer any need
for the iommu layer to be involved.

Further, the call sites of iommu_dma_compose_msi_msg() all follow the same
pattern of setting an MSI message address_hi/lo to non-translated and then
immediately calling iommu_dma_compose_msi_msg().

Refactor iommu_dma_compose_msi_msg() into msi_msg_set_addr() that directly
accepts the u64 version of the address and simplifies all the callers.

Move the new helper to linux/msi.h since it has nothing to do with iommu.

Aside from refactoring, this logically prepares for the next patch, which
allows multiple implementation options for iommu_dma_prepare_msi(). So, it
does not make sense to have the iommu_dma_compose_msi_msg() in dma-iommu.c
as it no longer provides the only iommu_dma_prepare_msi() implementation.

Link: https://patch.msgid.link/r/eda62a9bafa825e9cdabd7ddc61ad5a21c32af24.1740014950.git.nicolinc@nvidia.com
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

2 files changed, 28 insertions, 6 deletions

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 38c65e92ecd0..caee952febd4 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -1508,7 +1508,6 @@ static inline void iommu_debugfs_setup(void) {}
 int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
 
 int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr);
-void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg);
 
 #else /* CONFIG_IOMMU_DMA */
 
@@ -1524,11 +1523,6 @@ static inline int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_a
 {
 	return 0;
 }
-
-static inline void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
-{
-}
-
 #endif	/* CONFIG_IOMMU_DMA */
 
 /*
diff --git a/include/linux/msi.h b/include/linux/msi.h
index fc4f3774c3af..8d97b890faec 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -299,6 +299,34 @@ static inline void msi_desc_set_iommu_msi_iova(struct msi_desc *desc, u64 msi_io
 #endif
 }
 
+/**
+ * msi_msg_set_addr() - Set MSI address in an MSI message
+ *
+ * @desc:	MSI descriptor that may carry an IOVA base address for MSI via @iommu_msi_iova/shift
+ * @msg:	Target MSI message to set its address_hi and address_lo
+ * @msi_addr:	Physical address to set the MSI message
+ *
+ * Notes:
+ *  - Override @msi_addr using the IOVA base address in the @desc if @iommu_msi_shift is set
+ *  - Otherwise, simply set @msi_addr to @msg
+ */
+static inline void msi_msg_set_addr(struct msi_desc *desc, struct msi_msg *msg,
+				    phys_addr_t msi_addr)
+{
+#ifdef CONFIG_IRQ_MSI_IOMMU
+	if (desc->iommu_msi_shift) {
+		u64 msi_iova = desc->iommu_msi_iova << desc->iommu_msi_shift;
+
+		msg->address_hi = upper_32_bits(msi_iova);
+		msg->address_lo = lower_32_bits(msi_iova) |
+				  (msi_addr & ((1 << desc->iommu_msi_shift) - 1));
+		return;
+	}
+#endif
+	msg->address_hi = upper_32_bits(msi_addr);
+	msg->address_lo = lower_32_bits(msi_addr);
+}
+
 int msi_domain_insert_msi_desc(struct device *dev, unsigned int domid,
 			       struct msi_desc *init_desc);
 /**