[PATCH 1/4] iommu/amd: Drop unused global exclusion range fields and init

[Suravee Suthikulpanit]

Remove unused struct amd_iommu.exclusion_start/exclusion_length, the
MMIO_EXCL_* flag masks, and iommu_set_exclusion_range(). These struct
amd_iommu fields were never assigned, so early_enable_iommu() never
programmed the hardware exclusion registers through this path.

Please note that the exclusion range registers have been repurposed
to SNP completion-wait store base / limit registers. So, rename
MMIO_EXCL_BASE/LIMIT via to MMIO_COMPL_STORE_BASE/LIMIT instead.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
 drivers/iommu/amd/amd_iommu_types.h | 13 ++-----------
 drivers/iommu/amd/init.c            | 29 +++--------------------------
 2 files changed, 5 insertions(+), 37 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index c685d3771436..c4ea701b7cab 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -50,17 +50,13 @@
 #define MMIO_GET_BUS(x) (((x) & MMIO_RANGE_BUS_MASK) >> MMIO_RANGE_BUS_SHIFT)
 #define MMIO_MSI_NUM(x)	((x) & 0x1f)
 
-/* Flag masks for the AMD IOMMU exclusion range */
-#define MMIO_EXCL_ENABLE_MASK 0x01ULL
-#define MMIO_EXCL_ALLOW_MASK  0x02ULL
-
 /* Used offsets into the MMIO space */
 #define MMIO_DEV_TABLE_OFFSET   0x0000
 #define MMIO_CMD_BUF_OFFSET     0x0008
 #define MMIO_EVT_BUF_OFFSET     0x0010
 #define MMIO_CONTROL_OFFSET     0x0018
-#define MMIO_EXCL_BASE_OFFSET   0x0020
-#define MMIO_EXCL_LIMIT_OFFSET  0x0028
+#define MMIO_COMPL_STORE_BASE_OFFSET   0x0020
+#define MMIO_COMPL_STORE_LIMIT_OFFSET  0x0028
 #define MMIO_EXT_FEATURES	0x0030
 #define MMIO_PPR_LOG_OFFSET	0x0038
 #define MMIO_GA_LOG_BASE_OFFSET	0x00e0
@@ -680,11 +676,6 @@ struct amd_iommu {
 	/* pci domain of this IOMMU */
 	struct amd_iommu_pci_seg *pci_seg;
 
-	/* start of exclusion range of that IOMMU */
-	u64 exclusion_start;
-	/* length of exclusion range of that IOMMU */
-	u64 exclusion_length;
-
 	/* command buffer virtual address */
 	u8 *cmd_buf;
 	u32 cmd_buf_head;
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index f3fd7f39efb4..866249d3673e 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -352,28 +352,6 @@ static void iommu_write_l2(struct amd_iommu *iommu, u8 address, u32 val)
  *
  ****************************************************************************/
 
-/*
- * This function set the exclusion range in the IOMMU. DMA accesses to the
- * exclusion range are passed through untranslated
- */
-static void iommu_set_exclusion_range(struct amd_iommu *iommu)
-{
-	u64 start = iommu->exclusion_start & PAGE_MASK;
-	u64 limit = (start + iommu->exclusion_length - 1) & PAGE_MASK;
-	u64 entry;
-
-	if (!iommu->exclusion_start)
-		return;
-
-	entry = start | MMIO_EXCL_ENABLE_MASK;
-	memcpy_toio(iommu->mmio_base + MMIO_EXCL_BASE_OFFSET,
-			&entry, sizeof(entry));
-
-	entry = limit;
-	memcpy_toio(iommu->mmio_base + MMIO_EXCL_LIMIT_OFFSET,
-			&entry, sizeof(entry));
-}
-
 static void iommu_set_cwwb_range(struct amd_iommu *iommu)
 {
 	u64 start = iommu_virt_to_phys((void *)iommu->cmd_sem);
@@ -386,14 +364,14 @@ static void iommu_set_cwwb_range(struct amd_iommu *iommu)
 	 * Re-purpose Exclusion base/limit registers for Completion wait
 	 * write-back base/limit.
 	 */
-	memcpy_toio(iommu->mmio_base + MMIO_EXCL_BASE_OFFSET,
+	memcpy_toio(iommu->mmio_base + MMIO_COMPL_STORE_BASE_OFFSET,
 		    &entry, sizeof(entry));
 
 	/* Note:
 	 * Default to 4 Kbytes, which can be specified by setting base
 	 * address equal to the limit address.
 	 */
-	memcpy_toio(iommu->mmio_base + MMIO_EXCL_LIMIT_OFFSET,
+	memcpy_toio(iommu->mmio_base + MMIO_COMPL_STORE_LIMIT_OFFSET,
 		    &entry, sizeof(entry));
 }
 
@@ -1013,7 +991,7 @@ static int __init remap_or_alloc_cwwb_sem(struct amd_iommu *iommu)
 		 * completion wait buffer (CWB) address. Read and re-use it.
 		 */
 		pr_info_once("Re-using CWB buffers from the previous kernel\n");
-		paddr = readq(iommu->mmio_base + MMIO_EXCL_BASE_OFFSET) & PM_ADDR_MASK;
+		paddr = readq(iommu->mmio_base + MMIO_COMPL_STORE_BASE_OFFSET) & PM_ADDR_MASK;
 		iommu->cmd_sem = iommu_memremap(paddr, PAGE_SIZE);
 		if (!iommu->cmd_sem)
 			return -ENOMEM;
@@ -2891,7 +2869,6 @@ static void early_enable_iommu(struct amd_iommu *iommu)
 	iommu_set_device_table(iommu);
 	iommu_enable_command_buffer(iommu);
 	iommu_enable_event_buffer(iommu);
-	iommu_set_exclusion_range(iommu);
 	iommu_enable_gt(iommu);
 	iommu_enable_ga(iommu);
 	iommu_enable_xt(iommu);
-- 
2.34.1