From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wei.liu2@citrix.com>,
"Jan Beulich" <JBeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH] x86/setup: Avoid OoB E820 lookup when calculating the L1TF safe address
Date: Thu, 16 Aug 2018 16:27:57 +0100 [thread overview]
Message-ID: <1534433277-29436-1-git-send-email-andrew.cooper3@citrix.com> (raw)
A number of corner cases (most obviously, no-real-mode and no Multiboot memory
map) can end up with e820_raw.nr_map being 0, at which point the L1TF
calculation will underflow.
Spotted by Coverity.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
xen/arch/x86/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 727dad4..8d0f6f1 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -913,7 +913,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
/* Sanitise the raw E820 map to produce a final clean version. */
max_page = raw_max_page = init_e820(memmap_type, &e820_raw);
- if ( !efi_enabled(EFI_BOOT) )
+ if ( !efi_enabled(EFI_BOOT) && e820_raw.nr_map >= 1 )
{
/*
* Supplement the heuristics in l1tf_calculations() by assuming that
--
2.1.4
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
next reply other threads:[~2018-08-16 15:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-16 15:27 Andrew Cooper [this message]
2018-08-16 15:45 ` [PATCH] x86/setup: Avoid OoB E820 lookup when calculating the L1TF safe address Roger Pau Monné
2018-08-16 15:57 ` Jan Beulich
2018-08-16 17:02 ` Wei Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1534433277-29436-1-git-send-email-andrew.cooper3@citrix.com \
--to=andrew.cooper3@citrix.com \
--cc=JBeulich@suse.com \
--cc=roger.pau@citrix.com \
--cc=wei.liu2@citrix.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).