[PATCH v3 3/3] iommu/amd: Remove ad-hoc checks that are never true

[Rong Zhang]

The state transitions of the AMD IOMMU Initialization State Machine
imply that some ad-hoc checks will never be true. In detail, they are
only reachable if the previous state transitions have succeeded, but the
conditions are only true if the previous state transitions have failed.

Therefore, remove the redundant ad-hoc checks.

Signed-off-by: Rong Zhang <i@xxxxxxxx>
---
 drivers/iommu/amd/init.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 72b5b11b9d75..d81adb8efe0e 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -163,7 +163,6 @@ int amd_iommu_gpt_level = PAGE_MODE_4_LEVEL;
 int amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_VAPIC;
 static int amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
 
-static bool amd_iommu_detected;
 static bool amd_iommu_disabled __initdata;
 static bool amd_iommu_force_enable __initdata;
 static bool amd_iommu_irtcachedis;
@@ -3222,9 +3221,6 @@ static int __init early_amd_iommu_init(void)
 	acpi_status status;
 	u8 efr_hats, max_vasize;
 
-	if (!amd_iommu_detected)
-		return -ENODEV;
-
 	status = acpi_get_table("IVRS", 0, &ivrs_base);
 	if (status == AE_NOT_FOUND)
 		return -ENODEV;
@@ -3303,7 +3299,7 @@ static int __init early_amd_iommu_init(void)
 	}
 
 	/* Disable any previously enabled IOMMUs */
-	if (!is_kdump_kernel() || amd_iommu_disabled)
+	if (!is_kdump_kernel())
 		disable_iommus();
 
 	if (amd_iommu_irq_remap)
@@ -3398,12 +3394,6 @@ static __init void iommu_snp_enable(void)
 	if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
 		return;
 
-	/* SNP support required IOMMU to be ON */
-	if (no_iommu) {
-		pr_warn("SNP: IOMMU disabled, SNP cannot be supported.\n");
-		goto disable_snp;
-	}
-
 	amd_iommu_snp_mode0_sup = check_feature2(FEATURE_SNP_PAGE_MODE0_SUP);
 	/*
 	 * If SNP page mode 0 is not enabled, then SNP support requires that IOMMU
@@ -3716,7 +3706,6 @@ void __init amd_iommu_detect(void)
 	if (ret)
 		goto disable_snp;
 
-	amd_iommu_detected = true;
 	iommu_detected = 1;
 	x86_init.iommu.iommu_init = amd_iommu_init;
 	return;

-- 
2.55.0