On Sat, Nov 29, 2014 at 1:28 PM, Christoffer Dall
<christoffer.dall@xxxxxxxxxx> wrote:
> On Mon, Nov 24, 2014 at 11:26:51PM +0200, 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..81230da 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;
>> }
>>
>> +/**
>> + * kvm_handle_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;
>> +}
>> +
>> 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;
>> +
>
> Is this stuff always synchronously handled so that the mmio is properly
> populated upon handle_kernel_mmio on reads?
If I get it right the kvm_io_bus_ API is intended to work
synchronously. Of course it probably depends
on how the registered device handles the read/write call.
Or maybe I misunderstand your question? Please clarify in that case.
regards,
Nikolay Nikolaev
>
> -Christoffer
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