From: Julien Grall <julien@xen.org>
To: xen-devel@lists.xenproject.org
Cc: hongyxia@amazon.co.uk, iwj@xenproject.org,
Julien Grall <jgrall@amazon.com>, Jan Beulich <jbeulich@suse.com>,
Paul Durrant <paul@xen.org>
Subject: [PATCH for-4.15 v5 1/3] xen/iommu: x86: Don't try to free page tables is the IOMMU is not enabled
Date: Fri, 26 Feb 2021 10:56:38 +0000 [thread overview]
Message-ID: <20210226105640.12037-2-julien@xen.org> (raw)
In-Reply-To: <20210226105640.12037-1-julien@xen.org>
From: Julien Grall <jgrall@amazon.com>
When using CONFIG_BIGMEM=y, the page_list cannot be accessed whilst it
is is unitialized. However, iommu_free_pgtables() will be called even if
the domain is not using an IOMMU.
Consequently, Xen will try to go through the page list and deference a
NULL pointer.
Bail out early if the domain is not using an IOMMU.
Fixes: 15bc9a1ef51c ("x86/iommu: add common page-table allocator")
Signed-off-by: Julien Grall <jgrall@amazon.com>
---
Changes in v5:
- Patch added. This was split from "xen/x86: iommu: Ignore
IOMMU mapping requests when a domain is dying"
---
xen/drivers/passthrough/x86/iommu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c
index cea1032b3d02..58a330e82247 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -267,6 +267,9 @@ int iommu_free_pgtables(struct domain *d)
struct page_info *pg;
unsigned int done = 0;
+ if ( !is_iommu_enabled(d) )
+ return 0;
+
while ( (pg = page_list_remove_head(&hd->arch.pgtables.list)) )
{
free_domheap_page(pg);
--
2.17.1
next prev parent reply other threads:[~2021-02-26 10:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 10:56 [PATCH for-4.15 v5 0/3] xen/iommu: Collection of bug fixes for IOMMU teardown Julien Grall
2021-02-26 10:56 ` Julien Grall [this message]
2021-02-26 13:27 ` [PATCH for-4.15 v5 1/3] xen/iommu: x86: Don't try to free page tables is the IOMMU is not enabled Jan Beulich
2021-02-26 10:56 ` [PATCH for-4.15 v5 2/3] xen/x86: iommu: Ignore IOMMU mapping requests when a domain is dying Julien Grall
2021-02-26 13:30 ` Jan Beulich
2021-03-01 9:21 ` Julien Grall
2021-03-01 2:52 ` Tian, Kevin
2021-02-26 10:56 ` [PATCH for-4.15 v5 3/3] xen/iommu: x86: Clear the root page-table before freeing the page-tables Julien Grall
2021-03-01 2:54 ` Tian, Kevin
2021-03-02 9:56 ` [PATCH for-4.15 v5 0/3] xen/iommu: Collection of bug fixes for IOMMU teardown Julien Grall
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