Re: [PATCH] target/ppc: powerpc_excp: Guard ALIGNMENT interrupt with CONFIG_TCG

[Fabiano Rosas <farosas@linux.ibm.com>]

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 12/9/21 00:06, Fabiano Rosas wrote:
>> We cannot have TCG code in powerpc_excp because the function is called
>> from kvm-only code via ppc_cpu_do_interrupt:
>> 
>>  ../target/ppc/excp_helper.c:463:29: error: implicit declaration of
>>  function ‘cpu_ldl_code’ [-Werror=implicit-function-declaration]
>> 
>> Fortunately, the Alignment interrupt is not among the ones dispatched
>> from kvm-only code, so we can keep it out of the disable-tcg build for
>> now.
>> 
>> Fixes: 336e91f853 ("target/ppc: Move SPR_DSISR setting to powerpc_excp")
>> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
>> 
>> ---
>> 
>> Perhaps we could make powerpc_excp TCG only and have a separate
>> function that only knows the two interrupts that we use with KVM
>> (Program, Machine check). But for now this fix will do, I think.
>
> If KVM only uses 2 exception vectors, you could guard the
> enum in target/ppc/cpu.h using #ifdef'ry. While making the
> include uglier, it will helps to catch vector misused at
> compile time.

Yes, good point.

I just noticed that we also use System Reset with KVM. The other two are
kvm-only, but this one is in code shared with TCG, so it will need a bit
more work to disentangle. But should still be doable.

>> ---
>>  target/ppc/excp_helper.c | 2 ++
>>  1 file changed, 2 insertions(+)