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| author | Andres Lagar-Cavilla <andres@lagarcavilla.org> | 2012-01-26 13:21:27 +0000 |
|---|---|---|
| committer | Andres Lagar-Cavilla <andres@lagarcavilla.org> | 2012-01-26 13:21:27 +0000 |
| commit | 8e98287101d630a19d694fdfa01c5f716d96470c (patch) | |
| tree | 22a3dbcc016310f249bb60602e9205ed4b4eb6e2 /xen | |
| parent | ad6c917d7da2cc1dbcb6c8aa19ee0f9866d76f4e (diff) | |
| download | xen-8e98287101d630a19d694fdfa01c5f716d96470c.tar.gz xen-8e98287101d630a19d694fdfa01c5f716d96470c.tar.bz2 xen-8e98287101d630a19d694fdfa01c5f716d96470c.zip | |
x86/mm: Allow foreign read-only mappings of shared pages
Because shared pages are owned by dom_cow, the ownership test
while foreign mapping fails.
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>
Diffstat (limited to 'xen')
| -rw-r--r-- | xen/arch/x86/mm.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 2183bade33..fc954bb8e3 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -878,7 +878,8 @@ get_page_from_l1e( return 1; } - if ( unlikely(real_pg_owner != pg_owner) ) + if ( unlikely( (real_pg_owner != pg_owner) && + (real_pg_owner != dom_cow) ) ) { /* * Let privileged domains transfer the right to map their target @@ -892,6 +893,11 @@ get_page_from_l1e( pg_owner = real_pg_owner; } + /* Extra paranoid check for shared memory. Writable mappings + * disallowed (unshare first!) */ + if ( (l1f & _PAGE_RW) && (real_pg_owner == dom_cow) ) + goto could_not_pin; + /* Foreign mappings into guests in shadow external mode don't * contribute to writeable mapping refcounts. (This allows the * qemu-dm helper process in dom0 to map the domain's memory without |