Re: Fix prefix register checking in arch/s390/kvm/sigp.c

[Avi Kivity <avi@redhat.com>]

On 11/30/2009 06:14 PM, Carsten Otte wrote:
> This patch corrects the checking of the new address for the prefix register.
> On s390, the prefix register is used to address the cpu's lowcore (address
> 0...8k). This check is supposed to verify that the memory is readable and
> present.
> copy_from_guest is a helper function, that can be used to read from guest
> memory. It applies prefixing, adds the start address of the guest memory in
> user, and then calls copy_from_user. Previous code was obviously broken for
> two reasons:
> - prefixing should not be applied here. The current prefix register is
>    going to be updated soon, and the address we're looking for will be
>    0..8k after we've updated the register
> - we're adding the guest origin (gmsor) twice: once in subject code
>    and once in copy_from_guest
>
> With kuli, we did not hit this problem because (a) we were lucky with
> previous prefix register content, and (b) our guest memory was mmaped
> very low into user address space.
>
>    

Applied, thanks.

-- 
error compiling committee.c: too many arguments to function