[PATCH 1/4] iommu/amd: Check SNP support before enabling IOMMU

Ashish Kalra
2025-01-22T01:00:20Z

From: Vasant Hegde <vasant.hegde@amd.com>

iommu_snp_enable() checks for IOMMU feature support and page table
compatibility. Ideally this check should be done before enabling
IOMMUs. Currently its done after enabling IOMMUs. Also its causes
issue if kvm_amd is builtin.

Hence move SNP enable check before enabling IOMMUs.

Fixes: 04d65a9dbb33 ("iommu/amd: Don't rely on external callers to enable IOMMU SNP support")
Cc: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
---
drivers/iommu/amd/init.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index c5cd92edada0..419a0bc8eeea 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3256,13 +3256,14 @@ static int __init state_next(void)
}
break;
case IOMMU_ACPI_FINISHED:
+ /* SNP enable has to be called after early_amd_iommu_init() */
+ iommu_snp_enable();
early_enable_iommus();
x86_platform.iommu_shutdown = disable_iommus;
init_state = IOMMU_ENABLED;
break;
case IOMMU_ENABLED:
register_syscore_ops(&amd_iommu_syscore_ops);
- iommu_snp_enable();
ret = amd_iommu_init_pci();
init_state = ret ? IOMMU_INIT_ERROR : IOMMU_PCI_INIT;
break;
--
2.34.1