[PATCH v9 3/6] target-arm: kvm - support for single step

2015-11-12 Thread Alex Bennée 
This adds support for single-step. There isn't much to do on the QEMU
side as after we set-up the request for single step via the debug ioctl
it is all handled within the kernel.

Signed-off-by: Alex Bennée 

---
v2
  - convert to using HSR_EC
v3
  - use internals.h definitions
---
 target-arm/kvm.c | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/target-arm/kvm.c b/target-arm/kvm.c
index 50f70ef..d505a7e 100644
--- a/target-arm/kvm.c
+++ b/target-arm/kvm.c
@@ -535,6 +535,13 @@ static int kvm_handle_debug(CPUState *cs, struct kvm_run 
*run)
 kvm_cpu_synchronize_state(cs);
 
 switch (hsr_ec) {
+case EC_SOFTWARESTEP:
+if (cs->singlestep_enabled) {
+return true;
+} else {
+error_report("Came out of SINGLE STEP when not enabled");
+}
+break;
 case EC_AA64_BKPT:
 if (kvm_find_sw_breakpoint(cs, env->pc)) {
 return true;
@@ -595,6 +602,9 @@ int kvm_arch_on_sigbus(int code, void *addr)
 
 void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
 {
+if (cs->singlestep_enabled) {
+dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+}
 if (kvm_sw_breakpoints_active(cs)) {
 dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
 }
-- 
2.6.3

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Re: [PATCH v9 3/6] target-arm: kvm - support for single step

2015-11-20 Thread Peter Maydell 
On 12 November 2015 at 16:20, Alex Bennée  wrote:
> This adds support for single-step. There isn't much to do on the QEMU
> side as after we set-up the request for single step via the debug ioctl
> it is all handled within the kernel.
>
> Signed-off-by: Alex Bennée 
>
> ---
> v2
>   - convert to using HSR_EC
> v3
>   - use internals.h definitions
> ---
>  target-arm/kvm.c | 10 ++
>  1 file changed, 10 insertions(+)
>
> diff --git a/target-arm/kvm.c b/target-arm/kvm.c
> index 50f70ef..d505a7e 100644
> --- a/target-arm/kvm.c
> +++ b/target-arm/kvm.c
> @@ -535,6 +535,13 @@ static int kvm_handle_debug(CPUState *cs, struct kvm_run 
> *run)
>  kvm_cpu_synchronize_state(cs);
>
>  switch (hsr_ec) {
> +case EC_SOFTWARESTEP:
> +if (cs->singlestep_enabled) {
> +return true;
> +} else {
> +error_report("Came out of SINGLE STEP when not enabled");
> +}
> +break;
>  case EC_AA64_BKPT:
>  if (kvm_find_sw_breakpoint(cs, env->pc)) {
>  return true;
> @@ -595,6 +602,9 @@ int kvm_arch_on_sigbus(int code, void *addr)
>
>  void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
>  {
> +if (cs->singlestep_enabled) {
> +dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
> +}

Doesn't kvm_update_guest_debug() already set these bits, or am
I misreading it?

>  if (kvm_sw_breakpoints_active(cs)) {
>  dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
>  }
> --
> 2.6.3

thanks
-- PMM
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Re: [PATCH v9 3/6] target-arm: kvm - support for single step

2015-12-08 Thread Alex Bennée 

Peter Maydell  writes:

> On 12 November 2015 at 16:20, Alex Bennée  wrote:
>> This adds support for single-step. There isn't much to do on the QEMU
>> side as after we set-up the request for single step via the debug ioctl
>> it is all handled within the kernel.
>>
>> Signed-off-by: Alex Bennée 
>>
>> ---
>> v2
>>   - convert to using HSR_EC
>> v3
>>   - use internals.h definitions
>> ---
>>  target-arm/kvm.c | 10 ++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/target-arm/kvm.c b/target-arm/kvm.c
>> index 50f70ef..d505a7e 100644
>> --- a/target-arm/kvm.c
>> +++ b/target-arm/kvm.c
>> @@ -535,6 +535,13 @@ static int kvm_handle_debug(CPUState *cs, struct 
>> kvm_run *run)
>>  kvm_cpu_synchronize_state(cs);
>>
>>  switch (hsr_ec) {
>> +case EC_SOFTWARESTEP:
>> +if (cs->singlestep_enabled) {
>> +return true;
>> +} else {
>> +error_report("Came out of SINGLE STEP when not enabled");
>> +}
>> +break;
>>  case EC_AA64_BKPT:
>>  if (kvm_find_sw_breakpoint(cs, env->pc)) {
>>  return true;
>> @@ -595,6 +602,9 @@ int kvm_arch_on_sigbus(int code, void *addr)
>>
>>  void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
>>  {
>> +if (cs->singlestep_enabled) {
>> +dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
>> +}
>
> Doesn't kvm_update_guest_debug() already set these bits, or am
> I misreading it?

Yeah. This raises an interesting problem about what to do when we don't
have the capability. I could suppress those bits in the update function
but that seems a bit hacky.

Looking at the GDB capability code there doesn't seem to report
breakpoint capability short of just failing when you try to set one.

>
>>  if (kvm_sw_breakpoints_active(cs)) {
>>  dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
>>  }
>> --
>> 2.6.3
>
> thanks
> -- PMM


--
Alex Bennée
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