Commit b8f05c88 authored by Juergen Gross's avatar Juergen Gross Committed by David Vrabel

x86/xen: correct bug in p2m list initialization

Commit 054954eb ("xen: switch to
linear virtual mapped sparse p2m list") introduced an error.

During initialization of the p2m list a p2m identity area mapped by
a complete identity pmd entry has to be split up into smaller chunks
sometimes, if a non-identity pfn is introduced in this area.

If this non-identity pfn is not at index 0 of a p2m page the new
p2m page needed is initialized with wrong identity entries, as the
identity pfns don't start with the value corresponding to index 0,
but with the initial non-identity pfn. This results in weird wrong
mappings.

Correct the wrong initialization by starting with the correct pfn.

Cc: stable@vger.kernel.org # 3.19
Reported-by: default avatarStefan Bader <stefan.bader@canonical.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Tested-by: default avatarStefan Bader <stefan.bader@canonical.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 5054daa2
......@@ -563,7 +563,7 @@ static bool alloc_p2m(unsigned long pfn)
if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
p2m_init(p2m);
else
p2m_init_identity(p2m, pfn);
p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
spin_lock_irqsave(&p2m_update_lock, flags);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment