linux-kernel - [PATCH v8 13/13] iommu/amd: Disable iommu only if amd

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Message-Id: <1500627551-12930-14-git-send-email-bhe@redhat.com>
Date:   Fri, 21 Jul 2017 16:59:11 +0800
From:   Baoquan He <bhe@...hat.com>
To:     jroedel@...e.de
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        root <root@...-dinar-02.lab.bos.redhat.com>,
        Baoquan He <bhe@...hat.com>
Subject: [PATCH v8 13/13] iommu/amd: Disable iommu only if amd_iommu=off is specified

From: root <root@...-dinar-02.lab.bos.redhat.com>

It's ok to disable iommu in normal kernel. While there's no need
to disable it in kdump kernel after the on-flight dma issue has
heen fixed.

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 drivers/iommu/amd_iommu_init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 8b4bac978062..880f693c809b 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -2494,7 +2494,8 @@ static int __init early_amd_iommu_init(void)
 		goto out;
 
 	/* Disable any previously enabled IOMMUs */
-	disable_iommus();
+	if (amd_iommu_disabled)
+		disable_iommus();
 
 	if (amd_iommu_irq_remap)
 		amd_iommu_irq_remap = check_ioapic_information();
-- 
2.5.5