Re: [PATCH 3.4 152/177] KVM: x86: Fix uninitialized op->type for some immediate values

From: Zefan Li
Date: Wed Jan 28 2015 - 15:55:58 EST


On 2015/1/28 16:47, Nadav Amit wrote:
> This bug should have no effect on Linux 3.4. It shouldnât hurt, but the
> problem it fixes was introduced in 3.16 or 3.17.

Dropped. Thanks!

>
> Nadav
>
> lizf@xxxxxxxxxx wrote:
>
>> From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
>>
>> 3.4.106-rc1 review patch. If anyone has any objections, please let me know.
>>
>> ------------------
>>
>>
>> commit d29b9d7ed76c0b961603ca692b8a562556a20212 upstream.
>>
>> The emulator could reuse an op->type from a previous instruction for some
>> immediate values. If it mistakenly considers the operands as memory
>> operands, it will performs a memory read and overwrite op->val.
>>
>> Consider for instance the ROR instruction - src2 (the number of times)
>> would be read from memory instead of being used as immediate.
>>
>> Mark every immediate operand as such to avoid this problem.
>>
>> Fixes: c44b4c6ab80eef3a9c52c7b3f0c632942e6489aa
>> Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
>> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>


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