Alexander Graf wrote:
> 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 <ag...@suse.de>
>>> ---
>>> 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, ®s);
>>> 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.
Dunno about PPC in this regard and how much value it has, but we have
segment register access via gdb for x86.
>
> I definitely will implement SET_SREGS as soon as your sync split is in, as
> that's IMHO only really required on migration.
>
Migration is, of course, the major use case.
Still I wonder why not making this API symmetric when already touching it.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
