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From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org
Cc: joro@8bytes.org, jon.grimm@amd.com,
	Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: [PATCH] iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system
Date: Wed, 22 Apr 2020 08:30:02 -0500	[thread overview]
Message-ID: <1587562202-14183-1-git-send-email-suravee.suthikulpanit@amd.com> (raw)

Currently, system fails to boot because the legacy interrupt remapping
mode does not enable 128-bit IRTE (GA), which is required for x2APIC
support.

Fix by using AMD_IOMMU_GUEST_IR_LEGACY_GA mode when booting with
kernel option amd_iommu_intr=legacy instead. The initialization
logic will check GASup and automatically fallback to using
AMD_IOMMU_GUEST_IR_LEGACY if GA mode is not supported.

Fixes: 3928aa3f5775 ("iommu/amd: Detect and enable guest vAPIC support")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd_iommu_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 6be3853..2b9a67e 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -2936,7 +2936,7 @@ static int __init parse_amd_iommu_intr(char *str)
 {
 	for (; *str; ++str) {
 		if (strncmp(str, "legacy", 6) == 0) {
-			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
+			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
 			break;
 		}
 		if (strncmp(str, "vapic", 5) == 0) {
-- 
1.8.3.1


             reply	other threads:[~2020-04-22 13:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-22 13:30 Suravee Suthikulpanit [this message]
2020-04-26  0:28 ` [PATCH] iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system Suravee Suthikulpanit
2020-05-01 11:21 ` Joerg Roedel

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