On Mon, Jan 12, 2015 at 7:09 PM, Eric Auger <eric.auger@xxxxxxxxxx> wrote:
> Hi Nikolay,
> On 12/07/2014 10:37 AM, Nikolay Nikolaev wrote:
>> On IO memory abort, try to handle the MMIO access thorugh the KVM
>> registered read/write callbacks. This is done by invoking the relevant
>> kvm_io_bus_* API.
>>
>> Signed-off-by: Nikolay Nikolaev <n.nikolaev@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>> arch/arm/kvm/mmio.c | 33 +++++++++++++++++++++++++++++++++
>> 1 file changed, 33 insertions(+)
>>
>> diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
>> index 4cb5a93..e42469f 100644
>> --- a/arch/arm/kvm/mmio.c
>> +++ b/arch/arm/kvm/mmio.c
>> @@ -162,6 +162,36 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>> return 0;
>> }
>>
>> +/**
>> + * handle_kernel_mmio - handle an in-kernel MMIO access
>> + * @vcpu: pointer to the vcpu performing the access
>> + * @run: pointer to the kvm_run structure
>> + * @mmio: pointer to the data describing the access
>> + *
>> + * returns true if the MMIO access has been performed in kernel space,
>> + * and false if it needs to be emulated in user space.
>> + */
>> +static bool handle_kernel_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
>> + struct kvm_exit_mmio *mmio)
>> +{
>> + int ret;
>> +
>> + if (mmio->is_write) {
>> + ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, mmio->phys_addr,
>> + mmio->len, &mmio->data);
>> +
>> + } else {
>> + ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, mmio->phys_addr,
>> + mmio->len, &mmio->data);
>> + }
>> + if (!ret) {
>> + kvm_prepare_mmio(run, mmio);
>> + kvm_handle_mmio_return(vcpu, run);
>> + }
>> +
>> + return !ret;
> in case ret < 0 (-EOPNOTSUPP = -95) aren't we returning true too? return
> (ret==0)?
>
>> +}
>> +
>> int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
>> phys_addr_t fault_ipa)
>> {
>> @@ -200,6 +230,9 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
>> if (vgic_handle_mmio(vcpu, run, &mmio))
>> return 1;
>>
>> + if (handle_kernel_mmio(vcpu, run, &mmio))
>> + return 1;
>> +
>> kvm_prepare_mmio(run, &mmio);
>> return 0;
> currently the io_mem_abort returned value is not used by mmu.c code. I
> think this should be handed in kvm_handle_guest_abort. What do you think?
You're right that the returned value is not handled further after we
exit io_mem_abort, it's just passed up the call stack.
However I'm not sure how to handle it better. If you have ideas, please share.
regards,
Nikolay Nikolaev
>
> Best Regards
>
> Eric
>> }
>>
>
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