Re: [Qemu-devel] [PATCH qemu] spapr: Enable in-kernel H_SET_MODE handling

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 09/03/2015 09:18 AM, David Gibson wrote:
> On Wed, Sep 02, 2015 at 07:29:58PM +1000, Alexey Kardashevskiy wrote:
>> For setting debug watchpoints, sPAPR guests use H_SET_MODE hypercall.
>> The existing QEMU H_SET_MODE handler does not support this but
>> the KVM handler in HV KVM does. However it is not enabled.
>>
>> This enables the in-kernel H_SET_MODE handler which handles:
>> - Completed Instruction Address Breakpoint Register
>> - Watch point 0 registers.
>>
>> The rest is still handled in QEMU.
>>
>> Reported-by: Anton Blanchard <anton@samba.org>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>
> Won't this break auto-switching of VGA endianness, since that is
> triggered from the qemu implementation of H_SET_MODE?

Only breakpoints are handled in the kernel, at least in upstream and 
powerkvm, for the rest it is H_TOO_HARD and then handled in QEMU so it 
won't break endianness.


>
>> ---
>>   hw/ppc/spapr.c       | 1 +
>>   target-ppc/kvm.c     | 5 +++++
>>   target-ppc/kvm_ppc.h | 5 +++++
>>   3 files changed, 11 insertions(+)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index ae82565..7df0e15 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1728,6 +1728,7 @@ static void ppc_spapr_init(MachineState *machine)
>>       if (kvm_enabled()) {
>>           /* Enable H_LOGICAL_CI_* so SLOF can talk to in-kernel devices */
>>           kvmppc_enable_logical_ci_hcalls();
>> +        kvmppc_enable_set_mode_hcall();
>>       }
>>
>>       /* allocate RAM */
>> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
>> index 110436d..9cf5308 100644
>> --- a/target-ppc/kvm.c
>> +++ b/target-ppc/kvm.c
>> @@ -1953,6 +1953,11 @@ void kvmppc_enable_logical_ci_hcalls(void)
>>       kvmppc_enable_hcall(kvm_state, H_LOGICAL_CI_STORE);
>>   }
>>
>> +void kvmppc_enable_set_mode_hcall(void)
>> +{
>> +    kvmppc_enable_hcall(kvm_state, H_SET_MODE);
>> +}
>> +
>>   void kvmppc_set_papr(PowerPCCPU *cpu)
>>   {
>>       CPUState *cs = CPU(cpu);
>> diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
>> index 4d30e27..0714ba0 100644
>> --- a/target-ppc/kvm_ppc.h
>> +++ b/target-ppc/kvm_ppc.h
>> @@ -25,6 +25,7 @@ int kvmppc_get_hasidle(CPUPPCState *env);
>>   int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len);
>>   int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int level);
>>   void kvmppc_enable_logical_ci_hcalls(void);
>> +void kvmppc_enable_set_mode_hcall(void);
>>   void kvmppc_set_papr(PowerPCCPU *cpu);
>>   int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t cpu_version);
>>   void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy);
>> @@ -112,6 +113,10 @@ static inline void kvmppc_enable_logical_ci_hcalls(void)
>>   {
>>   }
>>
>> +static inline void kvmppc_enable_set_mode_hcall(void)
>> +{
>> +}
>> +
>>   static inline void kvmppc_set_papr(PowerPCCPU *cpu)
>>   {
>>   }
>


-- 
Alexey