[Qemu-devel] Re: [PATCH] PPC: Get MMU state on register sync

[Alexander Graf]

On 24.11.2009, at 19:01, Jan Kiszka wrote:

> Alexander Graf wrote:
>> While x86 only needs to sync cr0-4 to know all about its MMU state and enable
>> qemu to resolve virtual to physical addresses, we need to sync all of the
>> segment registers on PPC to know which mapping we're in.
>> 
>> So let's grab the segment register contents to be able to use the "x" monitor
>> command and also enable the gdbstub to resolve virtual addresses.
>> 
>> I sent the corresponding KVM patch to the KVM ML some minutes ago.
>> 
>> Signed-off-by: Alexander Graf <address@hidden>
>> ---
>> target-ppc/kvm.c |   30 ++++++++++++++++++++++++++++++
>> 1 files changed, 30 insertions(+), 0 deletions(-)
>> 
>> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
>> index 4e1c65f..566513f 100644
>> --- a/target-ppc/kvm.c
>> +++ b/target-ppc/kvm.c
>> @@ -98,12 +98,17 @@ int kvm_arch_put_registers(CPUState *env)
>> int kvm_arch_get_registers(CPUState *env)
>> {
>>     struct kvm_regs regs;
>> +    struct kvm_sregs sregs;
>>     uint32_t i, ret;
>> 
>>     ret = kvm_vcpu_ioctl(env, KVM_GET_REGS, &regs);
>>     if (ret < 0)
>>         return ret;
>> 
>> +    ret = kvm_vcpu_ioctl(env, KVM_GET_SREGS, &sregs);
>> +    if (ret < 0)
>> +        return ret;
>> +
>>     env->ctr = regs.ctr;
>>     env->lr = regs.lr;
>>     env->xer = regs.xer;
>> @@ -125,6 +130,31 @@ int kvm_arch_get_registers(CPUState *env)
>>     for (i = 0;i < 32; i++)
>>         env->gpr[i] = regs.gpr[i];
>> 
>> +#ifdef KVM_CAP_PPC_SEGSTATE
>> +    if (kvm_check_extension(env->kvm_state, KVM_CAP_PPC_SEGSTATE)) {
>> +        env->sdr1 = sregs.sdr1;
>> +    
>> +        /* Sync SLB */
>> +        for (i = 0; i < 64; i++) {
>> +            ppc_store_slb(env, sregs.ppc64.slb[i].slbe,
>> +                               sregs.ppc64.slb[i].slbv);
>> +        }
>> +    
>> +        /* Sync SRs */
>> +        for (i = 0; i < 16; i++) {
>> +            env->sr[i] = sregs.ppc32.sr[i];
>> +        }
>> +    
>> +        /* Sync BATs */
>> +        for (i = 0; i < 8; i++) {
>> +            env->DBAT[0][i] = sregs.ppc32.dbat[i] & 0xffffffff;
>> +            env->DBAT[1][i] = sregs.ppc32.dbat[i] >> 32;
>> +            env->IBAT[0][i] = sregs.ppc32.ibat[i] & 0xffffffff;
>> +            env->IBAT[1][i] = sregs.ppc32.ibat[i] >> 32;
>> +        }
>> +    }
>> +#endif
>> +
>>     return 0;
>> }
>> 
> 
> What about KVM_SET_SREGS in kvm_arch_put_registers? E.g. to play back
> potential changes to that special registers someone did via gdb?

I don't think you can actually change the segment values. At least I can't 
imagine why.

I definitely will implement SET_SREGS as soon as your sync split is in, as 
that's IMHO only really required on migration.


Alex