Jan Beulich
2011-Sep-21 11:10 UTC
[Xen-devel] [PATCH] VT-d: fix off-by-one error in RMRR validation
(base_addr,end_addr) is an inclusive range, and hence there shouldn''t
be a subtraction of 1 in the second invocation of page_is_ram_type().
For RMRRs covering a single page that actually resulted in the
immediately preceding page to get checked (which could have resulted
in a false warning).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -520,7 +520,7 @@ acpi_parse_one_rmrr(struct acpi_dmar_ent
* inform the user
*/
if ( (!page_is_ram_type(paddr_to_pfn(base_addr), RAM_TYPE_RESERVED)) ||
- (!page_is_ram_type(paddr_to_pfn(end_addr) - 1, RAM_TYPE_RESERVED)) )
+ (!page_is_ram_type(paddr_to_pfn(end_addr), RAM_TYPE_RESERVED)) )
{
dprintk(XENLOG_WARNING VTDPREFIX,
" RMRR address range not in reserved memory "
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Kay, Allen M
2011-Sep-21 20:37 UTC
[Xen-devel] RE: [PATCH] VT-d: fix off-by-one error in RMRR validation
Agree, it should not have subtracted 1 here. Good catch. Thanks!
Allen
-----Original Message-----
From: Jan Beulich [mailto:JBeulich@suse.com]
Sent: Wednesday, September 21, 2011 4:10 AM
To: xen-devel@lists.xensource.com
Cc: Kay, Allen M
Subject: [PATCH] VT-d: fix off-by-one error in RMRR validation
(base_addr,end_addr) is an inclusive range, and hence there shouldn''t
be a subtraction of 1 in the second invocation of page_is_ram_type().
For RMRRs covering a single page that actually resulted in the immediately
preceding page to get checked (which could have resulted in a false warning).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -520,7 +520,7 @@ acpi_parse_one_rmrr(struct acpi_dmar_ent
* inform the user
*/
if ( (!page_is_ram_type(paddr_to_pfn(base_addr), RAM_TYPE_RESERVED)) ||
- (!page_is_ram_type(paddr_to_pfn(end_addr) - 1, RAM_TYPE_RESERVED)) )
+ (!page_is_ram_type(paddr_to_pfn(end_addr), RAM_TYPE_RESERVED))
+ )
{
dprintk(XENLOG_WARNING VTDPREFIX,
" RMRR address range not in reserved memory "
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