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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Joerg Roedel <jroedel@suse.de>,
        Sasha Levin <sashal@kernel.org>,
        iommu@lists.linux-foundation.org
Subject: [PATCH AUTOSEL 5.6 46/50] iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system
Date:   Thu,  7 May 2020 10:27:22 -0400
Message-Id: <20200507142726.25751-46-sashal@kernel.org>
In-Reply-To: <20200507142726.25751-1-sashal@kernel.org>
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From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>

[ Upstream commit b74aa02d7a30ee5e262072a7d6e8deff10b37924 ]

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>
Link: https://lore.kernel.org/r/1587562202-14183-1-git-send-email-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 6be3853a5d978..2b9a67ecc6ac4 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) {
-- 
2.20.1