KVM: PPC: Book3S HV: radix: Fix uninitialized var build error

[Michael Ellerman]

On Tue, 2019-01-01 at 03:55:13 UTC, Michael Ellerman wrote:
> Old GCCs (4.6.3 at least), aren't able to follow the logic in
> __kvmhv_copy_tofrom_guest_radix() and warn that old_pid is used
> uninitialized:
> 
>   arch/powerpc/kvm/book3s_64_mmu_radix.c:75:3: error: 'old_pid' may be
>   used uninitialized in this function
> 
> The logic is OK, we only use old_pid if quadrant == 1, and in that
> case it has definitely be initialised, eg:
> 
> 	if (quadrant == 1) {
> 		old_pid = mfspr(SPRN_PID);
> 	...
> 	if (quadrant == 1 && pid != old_pid)
> 		mtspr(SPRN_PID, old_pid);
> 
> Annotate it to fix the error.
> 
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/f460772291f8171988b2b60141a457

cheers