diff mbox series

[2/3] iommu/amd: Don't call early_amd_iommu_init() when AMD IOMMU is disabled

Message ID 20210317091037.31374-3-joro@8bytes.org
State New
Headers show
Series [1/3] iommu/amd: Move Stoney Ridge check to detect_ivrs() | expand

Commit Message

Joerg Roedel March 17, 2021, 9:10 a.m. UTC 
From: Joerg Roedel <jroedel@suse.de>

Don't even try to initialize the AMD IOMMU hardware when amd_iommu=off has been
passed on the kernel command line.

References: https://bugzilla.kernel.org/show_bug.cgi?id=212133
References: https://bugzilla.suse.com/show_bug.cgi?id=1183132
Cc: stable@vger.kernel.org # v5.11
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd/init.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Joerg Roedel March 17, 2021, 2:24 p.m. UTC | #1 
On Wed, Mar 17, 2021 at 01:37:16PM +0000, David Woodhouse wrote:
> If we can get to the point where we don't even need to check
> amd_iommu_irq_remap in the ...select() function because the IRQ domain
> is never even registered in the case where the flag ends up false, all
> the better :)

This should already be achieved with this patch :)

But the check is still needed if something goes wrong during IOMMU
initialization. In this case the IOMMUs are teared down and the memory
is freed. But the IRQ domains stay registered for now, mostly because
the upper-level APIs to register them lack a deregister function.

I havn't looked into the details yet whether it is suffient to call
irq_domain_remove() on a domain created with
arch_create_remap_msi_irq_domain() for example. This needs more research
on my side :)

Regards,

	Joerg
diff mbox series

Patch

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 3280e6f5b720..61dae1800b7f 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -2919,12 +2919,12 @@  static int __init state_next(void)
 		}
 		break;
 	case IOMMU_IVRS_DETECTED:
-		ret = early_amd_iommu_init();
-		init_state = ret ? IOMMU_INIT_ERROR : IOMMU_ACPI_FINISHED;
-		if (init_state == IOMMU_ACPI_FINISHED && amd_iommu_disabled) {
-			pr_info("AMD IOMMU disabled\n");
+		if (amd_iommu_disabled) {
 			init_state = IOMMU_CMDLINE_DISABLED;
 			ret = -EINVAL;
+		} else {
+			ret = early_amd_iommu_init();
+			init_state = ret ? IOMMU_INIT_ERROR : IOMMU_ACPI_FINISHED;
 		}
 		break;
 	case IOMMU_ACPI_FINISHED: