[PATCH] KVM: x86: Fix 32-bit build breakage due to typo

[Jan Kiszka <jan.kiszka@web.de>]

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Avi Kivity wrote:
> On 03/17/2010 09:45 AM, Jan Kiszka wrote:
>> Avi Kivity wrote:
>>   
>>> Once upon a time, locked operations were emulated while holding the
>>> mmu mutex.
>>> Since mmu pages were write protected, it was safe to emulate the
>>> writes in
>>> a non-atomic manner, since there could be no other writer, either in the
>>> guest or in the kernel.
>>>
>>> These days emulation takes place without holding the mmu spinlock, so
>>> the
>>> write could be preempted by an unshadowing event, which exposes the page
>>> to writes by the guest.  This may cause corruption of guest page tables.
>>>
>>> Fix by using an atomic cmpxchg for these operations.
>>>
>>> Signed-off-by: Avi Kivity<avi@redhat.com>
>>> ---
>>>   arch/x86/kvm/x86.c |   69
>>> ++++++++++++++++++++++++++++++++++++----------------
>>>   1 files changed, 48 insertions(+), 21 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 9d02cc7..d724a52 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -3299,41 +3299,68 @@ int emulator_write_emulated(unsigned long addr,
>>>   }
>>>   EXPORT_SYMBOL_GPL(emulator_write_emulated);
>>>
>>> +#define CMPXCHG_TYPE(t, ptr, old, new) \
>>> +    (cmpxchg((t *)(ptr), *(t *)(old), *(t *)(new)) == *(t *)(old))
>>> +
>>> +#ifdef CONFIG_X86_64
>>> +#  define CMPXCHG64(ptr, old, new) CMPXCHG_TYPE(u64, ptr, old, new)
>>> +#else
>>> +#  define CMPXCHG64(ptr, old, new) \
>>> +    (cmpxchg64((u64 *)(ptr), *(u64 *)(old), *(u *)(new)) == *(u64
>>> *)(old))
>>>      
>>                                                  ^^^^^^
>> This should cause the 32-bit build breakage I see with the current next
>> branch.
>>    
> 
> Also, Marcelo sees autotest breakage, so it's also broken on 64-bit
> somehow.
> 

Obviously, the 64-bit case is considered stable now and 32 bit remained
untested (not included in autotest?). So here is the build fix:

---------->

KVM: x86: Fix 32-bit build breakage due to typo

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 arch/x86/kvm/x86.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bb9a24a..097ad3a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3322,7 +3322,7 @@ EXPORT_SYMBOL_GPL(emulator_write_emulated);
 #  define CMPXCHG64(ptr, old, new) CMPXCHG_TYPE(u64, ptr, old, new)
 #else
 #  define CMPXCHG64(ptr, old, new) \
-	(cmpxchg64((u64 *)(ptr), *(u64 *)(old), *(u *)(new)) == *(u64 *)(old))
+	(cmpxchg64((u64 *)(ptr), *(u64 *)(old), *(u64 *)(new)) == *(u64 *)(old))
 #endif
 
 static int emulator_cmpxchg_emulated(unsigned long addr,
-- 
1.6.0.2


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