Re: [PATCH V1 09/16] arm/ioreq: Introduce arch specific bits for IOREQ/DM features

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.09.2020 22:16, Oleksandr wrote:
> On 23.09.20 21:03, Julien Grall wrote:
>> On 10/09/2020 21:22, Oleksandr Tyshchenko wrote:
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>>> @@ -91,6 +108,28 @@ struct arch_domain
>>>   #endif
>>>   }  __cacheline_aligned;
>>>   +enum hvm_io_completion {
>>> +    HVMIO_no_completion,
>>> +    HVMIO_mmio_completion,
>>> +    HVMIO_pio_completion
>>> +};
>>> +
>>> +struct hvm_vcpu_io {
>>> +    /* I/O request in flight to device model. */
>>> +    enum hvm_io_completion io_completion;
>>> +    ioreq_t                io_req;
>>> +
>>> +    /*
>>> +     * HVM emulation:
>>> +     *  Linear address @mmio_gla maps to MMIO physical frame 
>>> @mmio_gpfn.
>>> +     *  The latter is known to be an MMIO frame (not RAM).
>>> +     *  This translation is only valid for accesses as per 
>>> @mmio_access.
>>> +     */
>>> +    struct npfec        mmio_access;
>>> +    unsigned long       mmio_gla;
>>> +    unsigned long       mmio_gpfn;
>>> +};
>>> +
>>
>> Why do we need to re-define most of this? Can't this just be in common 
>> code?
> 
> Jan asked almost the similar question in "[PATCH V1 02/16] xen/ioreq: 
> Make x86's IOREQ feature common".
> Please see my answer there:
> https://patchwork.kernel.org/patch/11769105/#23637511
> 
> Theoretically we could move this to the common code, but the question is 
> how to be with other struct fields the x86's struct hvm_vcpu_io 
> has/needs but
> Arm's seems not, would it be possible to logically split struct 
> hvm_vcpu_io into common and arch parts?

Have struct vcpu_io and struct arch_vcpu_io as a sub-part of it?

Jan