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| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-01-18 20:17:10 -0500 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-03-14 11:17:09 -0400 |
| commit | c7617798771ad588d585986d896197c04b737621 (patch) | |
| tree | 120b3d73e9e8c808083489770e5324c60e1ce8ec /arch | |
| parent | fb38923ead10aa8a28db191548e176e8856614d7 (diff) | |
| download | linux-3.10-c7617798771ad588d585986d896197c04b737621.tar.gz linux-3.10-c7617798771ad588d585986d896197c04b737621.tar.bz2 linux-3.10-c7617798771ad588d585986d896197c04b737621.zip | |
xen/mmu: WARN_ON when racing to swap middle leaf.
The initial bootup code uses set_phys_to_machine quite a lot, and after
bootup it would be used by the balloon driver. The balloon driver does have
mutex lock so this should not be necessary - but just in case, add
a WARN_ON if we do hit this scenario. If we do fail this, it is OK
to continue as there is a backup mechanism (VM_IO) that can bypass
the P2M and still set the _PAGE_IOMAP flags.
[v2: Change from WARN to BUG_ON]
[v3: Rebased on top of xen->p2m code split]
[v4: Change from BUG_ON to WARN]
Reviewed-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/xen/p2m.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 809fe353630..4631cf99e71 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -605,7 +605,8 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) /* Swap over from MISSING to IDENTITY if needed. */ if (p2m_top[topidx][mididx] == p2m_missing) { - p2m_top[topidx][mididx] = p2m_identity; + WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing, + p2m_identity) != p2m_missing); return true; } } |