Re: [PATCH v3 31/34] xen/riscv: add minimal stuff to mm.h to build full Xen

[Jan Beulich <jbeulich@xxxxxxxx>]

On 02.02.2024 18:30, Oleksii wrote:
> On Tue, 2024-01-23 at 14:03 +0100, Jan Beulich wrote:
>> On 22.12.2023 16:13, Oleksii Kurochko wrote:
>>> +/* Convert between Xen-heap virtual addresses and machine frame
>>> numbers. */
>>> +#define __virt_to_mfn(va) (virt_to_maddr(va) >> PAGE_SHIFT)
>>> +#define __mfn_to_virt(mfn) maddr_to_virt((paddr_t)(mfn) <<
>>> PAGE_SHIFT)
>>
>> These would imo better use maddr_to_mfn() and mfn_to_maddr(), rather
>> than
>> kind of open-coding them. The former could also use PFN_DOWN() as an
>> alternative.
> We can't to as __virt_to_mfn() when is used it is usually wrapped by
> _mfn() which expect to have unsigned long as an argument.

#define __virt_to_mfn(va)  mfn_x(maddr_to_mfn(virt_to_maddr(va))
#define __mfn_to_virt(mfn) maddr_to_virt(mfn_to_maddr(_mfn(mfn)))

?

>>> +/* Convert between Xen-heap virtual addresses and page-info
>>> structures. */
>>> +static inline struct page_info *virt_to_page(const void *v)
>>> +{
>>> +    BUG();
>>> +    return NULL;
>>> +}
>>> +
>>> +/*
>>> + * We define non-underscored wrappers for above conversion
>>> functions.
>>> + * These are overriden in various source files while underscored
>>> version
>>> + * remain intact.
>>> + */
>>> +#define virt_to_mfn(va)     __virt_to_mfn(va)
>>> +#define mfn_to_virt(mfn)    __mfn_to_virt(mfn)
>>
>> Is this really still needed? Would be pretty nice if in a new port we
>> could get to start cleanly right away (i.e. by not needing per-file
>> overrides, but using type-safe expansions here right away).
> We still need __virt_to_mfn and __mfn_to_virt as common code use them:
>  * xen/common/xenoprof.c:24:#define virt_to_mfn(va)
> mfn(__virt_to_mfn(va))

Are you meaning to enable this code on RISC-V.

>  * xen/include/xen/domain_page.h:59:#define domain_page_map_to_mfn(ptr)
> _mfn(__virt_to_mfn((unsigned long)(ptr)))

Hmm, yes, we should finally get this sorted. But yeah, not something I want
to ask you to do.

Jan