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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	iommu@lists.linux-foundation.org, Joerg Roedel <jroedel@suse.de>
Subject: [PATCH AUTOSEL 5.6 41/62] iommu/amd: Do not loop forever when trying to increase address space
Date: Thu, 14 May 2020 14:51:26 -0400	[thread overview]
Message-ID: <20200514185147.19716-41-sashal@kernel.org> (raw)
In-Reply-To: <20200514185147.19716-1-sashal@kernel.org>

From: Joerg Roedel <jroedel@suse.de>

[ Upstream commit 5b8a9a047b6cad361405c7900c1e1cdd378c4589 ]

When increase_address_space() fails to allocate memory, alloc_pte()
will call it again until it succeeds. Do not loop forever while trying
to increase the address space and just return an error instead.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200504125413.16798-3-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iommu/amd_iommu.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 28229a38af4d2..68da484a69dd0 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1489,8 +1489,19 @@ static u64 *alloc_pte(struct protection_domain *domain,
 	amd_iommu_domain_get_pgtable(domain, &pgtable);
 
 	while (address > PM_LEVEL_SIZE(pgtable.mode)) {
-		*updated = increase_address_space(domain, address, gfp) || *updated;
+		bool upd = increase_address_space(domain, address, gfp);
+
+		/* Read new values to check if update was successful */
 		amd_iommu_domain_get_pgtable(domain, &pgtable);
+
+		/*
+		 * Return an error if there is no memory to update the
+		 * page-table.
+		 */
+		if (!upd && (address > PM_LEVEL_SIZE(pgtable.mode)))
+			return NULL;
+
+		*updated = *updated || upd;
 	}
 
 
-- 
2.20.1

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  parent reply	other threads:[~2020-05-14 18:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200514185147.19716-1-sashal@kernel.org>
2020-05-14 18:51 ` [PATCH AUTOSEL 5.6 40/62] iommu/amd: Fix race in increase_address_space()/fetch_pte() Sasha Levin
2020-05-14 18:51 ` Sasha Levin [this message]
2020-05-14 18:51 ` [PATCH AUTOSEL 5.6 42/62] iommu/amd: Call domain_flush_complete() in update_domain() Sasha Levin
2020-05-14 18:51 ` [PATCH AUTOSEL 5.6 43/62] iommu/amd: Update Device Table in increase_address_space() Sasha Levin

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