> Am 23.08.2014 um 12:17 schrieb Madhavan Srinivasan <ma...@linux.vnet.ibm.com>:
>
>> On Thursday 21 August 2014 02:40 PM, Alexander Graf wrote:
>>
>>
>>> On 20.08.14 07:52, Madhavan Srinivasan wrote:
>>> This patch adds kernel side support for software breakpoint.
>>> Design is that, by using an illegal instruction, we trap to hypervisor
>>> via Emulation Assistance interrupt, where we check for the illegal
>>> instruction
>>> and accordingly we return to Host or Guest. Patch also adds support for
>>> software breakpoint in PR KVM.
>>>
>>> Changes v3->v4:
>>> Made changes to code comments and removed #define of zero opcode
>>> Added a new function to handle the debug instruction emulation in book3s_hv
>>> Rebased the code to latest upstream source.
>>>
>>> Changes v2->v3:
>>> Changed the debug instructions. Using the all zero opcode in the
>>> instruction word
>>> as illegal instruction as mentioned in Power ISA instead of ABS
>>> Removed reg updated in emulation assist and added a call to
>>> kvmppc_emulate_instruction for reg update.
>>>
>>> Changes v1->v2:
>>>
>>> Moved the debug instruction #def to kvm_book3s.h. This way PR_KVM can also
>>> share it.
>>> Added code to use KVM get one reg infrastructure to get debug opcode.
>>> Updated emulate.c to include emulation of debug instruction incase of
>>> PR_KVM.
>>> Made changes to commit message.
>>>
>>> Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
>>> ---
>>> arch/powerpc/include/asm/kvm_book3s.h | 7 +++++++
>>> arch/powerpc/kvm/book3s.c | 3 ++-
>>> arch/powerpc/kvm/book3s_hv.c | 32 ++++++++++++++++++++++++++++++--
>>> arch/powerpc/kvm/book3s_pr.c | 3 +++
>>> arch/powerpc/kvm/emulate.c | 11 +++++++++++
>>> 5 files changed, 53 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/kvm_book3s.h
>>> b/arch/powerpc/include/asm/kvm_book3s.h
>>> index 6acf0c2..a1944f8 100644
>>> --- a/arch/powerpc/include/asm/kvm_book3s.h
>>> +++ b/arch/powerpc/include/asm/kvm_book3s.h
>>> @@ -24,6 +24,13 @@
>>> #include <linux/kvm_host.h>
>>> #include <asm/kvm_book3s_asm.h>
>>>
>>> +/*
>>> + * KVMPPC_INST_BOOK3S_DEBUG is debug Instruction for supporting Software
>>> Breakpoint.
>>> + * Based on PowerISA v2.07, Instruction with primary opcode 0 will be
>>> treated as illegal
>>> + * instruction.
>>> + */
>>> +#define KVMPPC_INST_BOOK3S_DEBUG 0x00dddd00
>>
>> Please change the BookE version of this as well, put the define in a
>> common header and use a non book specific name.
>
> I first wanted to get the server side in and then take up this, but i
> can do it with this, just concerned incase of booke testing :(
I can test, no problem. You can at least do compile tests on your side already
;)
>
>>> +
>>> struct kvmppc_bat {
>>> u64 raw;
>>> u32 bepi;
>>> diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
>>> index dd03f6b..00e9c9f 100644
>>> --- a/arch/powerpc/kvm/book3s.c
>>> +++ b/arch/powerpc/kvm/book3s.c
>>> @@ -778,7 +778,8 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
>>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>>> struct kvm_guest_debug *dbg)
>>> {
>>> - return -EINVAL;
>>> + vcpu->guest_debug = dbg->control;
>>> + return 0;
>>> }
>>>
>>> void kvmppc_decrementer_func(unsigned long data)
>>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>>> index 27cced9..0a92e45 100644
>>> --- a/arch/powerpc/kvm/book3s_hv.c
>>> +++ b/arch/powerpc/kvm/book3s_hv.c
>>> @@ -725,6 +725,14 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd)
>>> return kvmppc_hcall_impl_hv_realmode(cmd);
>>> }
>>>
>>> +static int kvmppc_emulate_debug_instruction_hv(struct kvm_run *run,
>>> + struct kvm_vcpu *vcpu)
>>> +{
>>> + run->exit_reason = KVM_EXIT_DEBUG;
>>> + run->debug.arch.address = kvmppc_get_pc(vcpu);
>>> + return 0;
>>> +}
>>> +
>>> static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu,
>>> struct task_struct *tsk)
>>> {
>>> @@ -811,9 +819,26 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run,
>>> struct kvm_vcpu *vcpu,
>>> * we don't emulate any guest instructions at this stage.
>>
>> This comment is no longer true, it should get changed.
>
> Will change it.
>
>>> */
>>> case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
>>> - kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>>> - r = RESUME_GUEST;
>>> + {
>>> + u32 last_inst;
>>> + if(kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
>>> + EMULATE_DONE) {
>>
>> Please only do this if debugging is active.
>
> Ok sure. But i will add in the else part of the check. Since we do the
> instruction check there.
We should only fetch the instruction if sw breakpoint debugging is active.
Alex
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