Re: [Qemu-arm] [PATCH v14 5/9] target-arm: kvm64: inject synchronous External Abort

[gengdongjiu]

Hi Peter,

On 2018/1/13 13:24, gengdongjiu wrote:
>>> +
>>> +    /* For the AArch64, instruction length is 32-bit */
>>> +    esr |= ARM_EL_IL;
>>> +    env->exception.syndrome = esr;
>>> +
>>> +    cc->do_interrupt(c);
>>> +
>>> +    /* set ESR_EL1 */
>>> +    ret = kvm_arm_cpreg_value(cpu, offsetof(CPUARMState, cp15.esr_el[1]));
>> Breakpoint injection doesn't need to do this. Neither should this code.
> As my above explanation, in the KVM mode, it needs to set the ESR_ELx in 
> extra method.
> the cc->do_interrupt(c) does not set ESR_ELx. so I use kvm_arm_cpreg_value()
> to set it. whether you have better method to set the ESR_Elx except for my 
> method?  Thanks.

If QEMU changes the KVM's registers, it needs to call write_list_to_kvmstate() 
to write the cpu->cpreg_values[] list
to KVM through KVM_SET_ONE_REG IOCTL[1]. In Qemu, now it should not have 
software path to change the cpu->cpreg_values[] list
except write_cpustate_to_list(). Here I can also call write_cpustate_to_list() 
instead of kvm_arm_cpreg_value() to change
cpu->cpreg_values[] list, but the write_cpustate_to_list() will write all the 
coprocessor state to the cpu->cpreg_values[] list,
we can not sure all the coprocessor states are right, so here I only change 
corresponding index value in this list using kvm_arm_cpreg_value().

Breakpoint injection that you mentioned should not change KVM register or not 
in the KVM mode.

[1]:
 kvm_arch_put_registers()
  -> write_list_to_kvmstate()
    -> write cpu->cpreg_values[] to the kernel KVM through KVM_SET_ONE_REG

> 
> 
>>> +    if (ret) {
>>> +        fprintf(stderr, "<%s> failed to set esr_el1\n", __func__);
>>> +        abort();
>>> +    }
>>> +}
>>> +
>>>  #define AARCH64_CORE_REG(x)   (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
>>>                   KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
>>>
>>> --
>>> 1.8.3.1