[PATCH] iommu/amd: remove amd_iommu_snp_enable

* [PATCH] iommu/amd: remove amd_iommu_snp_enable
@ 2023-08-31 12:31 Christoph Hellwig
  2023-08-31 18:03 ` Kim Phillips
  0 siblings, 1 reply; 6+ messages in thread
From: Christoph Hellwig @ 2023-08-31 12:31 UTC (permalink / raw)
  To: joro; +Cc: suravee.suthikulpanit, iommu

amd_iommu_snp_enable is unused and has been since it was added in commit
fb2accadaa94 ("iommu/amd: Introduce function to check and enable SNP").

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/amd/init.c  | 38 --------------------------------------
 include/linux/amd-iommu.h |  4 ----
 2 files changed, 42 deletions(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index ea0f1ab9417837..9f22e469da973b 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3744,41 +3744,3 @@ int amd_iommu_pc_set_reg(struct amd_iommu *iommu, u8 bank, u8 cntr, u8 fxn, u64
 
 	return iommu_pc_get_set_reg(iommu, bank, cntr, fxn, value, true);
 }
-
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-int amd_iommu_snp_enable(void)
-{
-	/*
-	 * The SNP support requires that IOMMU must be enabled, and is
-	 * not configured in the passthrough mode.
-	 */
-	if (no_iommu || iommu_default_passthrough()) {
-		pr_err("SNP: IOMMU is disabled or configured in passthrough mode, SNP cannot be supported");
-		return -EINVAL;
-	}
-
-	/*
-	 * Prevent enabling SNP after IOMMU_ENABLED state because this process
-	 * affect how IOMMU driver sets up data structures and configures
-	 * IOMMU hardware.
-	 */
-	if (init_state > IOMMU_ENABLED) {
-		pr_err("SNP: Too late to enable SNP for IOMMU.\n");
-		return -EINVAL;
-	}
-
-	amd_iommu_snp_en = check_feature_on_all_iommus(FEATURE_SNP);
-	if (!amd_iommu_snp_en)
-		return -EINVAL;
-
-	pr_info("SNP enabled\n");
-
-	/* Enforce IOMMU v1 pagetable when SNP is enabled. */
-	if (amd_iommu_pgtable != AMD_IOMMU_V1) {
-		pr_warn("Force to using AMD IOMMU v1 page table due to SNP\n");
-		amd_iommu_pgtable = AMD_IOMMU_V1;
-	}
-
-	return 0;
-}
-#endif
diff --git a/include/linux/amd-iommu.h b/include/linux/amd-iommu.h
index 953e6f12fa1c30..58e6c3806c09d4 100644
--- a/include/linux/amd-iommu.h
+++ b/include/linux/amd-iommu.h
@@ -206,8 +206,4 @@ int amd_iommu_pc_get_reg(struct amd_iommu *iommu, u8 bank, u8 cntr, u8 fxn,
 		u64 *value);
 struct amd_iommu *get_amd_iommu(unsigned int idx);
 
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-int amd_iommu_snp_enable(void);
-#endif
-
 #endif /* _ASM_X86_AMD_IOMMU_H */
-- 
2.39.2


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