From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Tim Deegan" <tim@xen.org>,
"George Dunlap" <george.dunlap@citrix.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>,
"Ian Jackson" <iwj@xenproject.org>
Subject: [PATCH][4.15] x86/shadow: replace bogus return path in shadow_get_page_from_l1e()
Date: Fri, 26 Feb 2021 16:08:33 +0100 [thread overview]
Message-ID: <d6cf1205-d537-fafb-a082-e973bfe11315@suse.com> (raw)
Prior to be640b1800bb ("x86: make get_page_from_l1e() return a proper
error code") a positive return value did indicate an error. Said commit
failed to adjust this return path, but luckily the only caller has
always been inside a shadow_mode_refcounts() conditional.
Subsequent changes caused 1 to end up at the default (error) label in
the caller's switch() again, but the returning of 1 (== _PAGE_PRESENT)
is still rather confusing here, and a latent risk.
Convert to an ASSERT() instead, just in case any new caller would
appear.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -802,9 +802,7 @@ shadow_get_page_from_l1e(shadow_l1e_t sl
struct domain *owner;
ASSERT(!sh_l1e_is_magic(sl1e));
-
- if ( !shadow_mode_refcounts(d) )
- return 1;
+ ASSERT(shadow_mode_refcounts(d));
res = get_page_from_l1e(sl1e, d, d);
next reply other threads:[~2021-02-26 15:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 15:08 Jan Beulich [this message]
2021-02-26 15:14 ` [PATCH][4.15] x86/shadow: replace bogus return path in shadow_get_page_from_l1e() Jan Beulich
2021-03-01 17:26 ` Ian Jackson
2021-02-26 15:21 ` Andrew Cooper
2021-03-01 17:26 ` Ian Jackson
2021-02-26 16:57 ` Tim Deegan
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