linux-kernel - [PATCH 4/5] iommu/amd: Hold the domain lock when calling iommu_map

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Date:   Tue, 10 Sep 2019 19:49:24 +0200
From:   Filippo Sironi <sironi@...zon.de>
To:     sironi@...zon.de, joro@...tes.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] iommu/amd: Hold the domain lock when calling iommu_map_page

iommu_map_page calls into __domain_flush_pages, which requires the
domain lock since it traverses the device list, which the lock protects.

Signed-off-by: Filippo Sironi <sironi@...zon.de>
---
 drivers/iommu/amd_iommu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index d4f25767622e..3714ae5ded31 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2562,6 +2562,7 @@ static int map_sg(struct device *dev, struct scatterlist *sglist,
 	unsigned long address;
 	u64 dma_mask;
 	int ret;
+	unsigned long flags;
 
 	domain = get_domain(dev);
 	if (IS_ERR(domain))
@@ -2587,7 +2588,9 @@ static int map_sg(struct device *dev, struct scatterlist *sglist,
 
 			bus_addr  = address + s->dma_address + (j << PAGE_SHIFT);
 			phys_addr = (sg_phys(s) & PAGE_MASK) + (j << PAGE_SHIFT);
+			spin_lock_irqsave(&domain->lock, flags);
 			ret = iommu_map_page(domain, bus_addr, phys_addr, PAGE_SIZE, prot, GFP_ATOMIC);
+			spin_unlock_irqrestore(&domain->lock, flags);
 			if (ret)
 				goto out_unmap;
 
@@ -3095,7 +3098,9 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
 		prot |= IOMMU_PROT_IW;
 
 	mutex_lock(&domain->api_lock);
+	spin_lock(&domain->lock);
 	ret = iommu_map_page(domain, iova, paddr, page_size, prot, GFP_KERNEL);
+	spin_unlock(&domain->lock);
 	mutex_unlock(&domain->api_lock);
 
 	domain_flush_np_cache(domain, iova, page_size);
-- 
2.7.4