Re: [PATCH v5 19/23] xen/riscv: add minimal stuff to mm.h to build full Xen

[Jan Beulich <jbeulich@suse.com>]

On 26.02.2024 18:39, Oleksii Kurochko wrote:
> --- a/xen/arch/riscv/include/asm/mm.h
> +++ b/xen/arch/riscv/include/asm/mm.h
> @@ -3,11 +3,252 @@
>  #ifndef _ASM_RISCV_MM_H
>  #define _ASM_RISCV_MM_H
>  
> +#include <public/xen.h>
> +#include <xen/bug.h>
> +#include <xen/mm-frame.h>
> +#include <xen/pdx.h>
> +#include <xen/types.h>
> +
>  #include <asm/page-bits.h>
>  
>  #define pfn_to_paddr(pfn) ((paddr_t)(pfn) << PAGE_SHIFT)
>  #define paddr_to_pfn(pa)  ((unsigned long)((pa) >> PAGE_SHIFT))
>  
> +#define paddr_to_pdx(pa)    mfn_to_pdx(maddr_to_mfn(pa))
> +#define gfn_to_gaddr(gfn)   pfn_to_paddr(gfn_x(gfn))
> +#define gaddr_to_gfn(ga)    _gfn(paddr_to_pfn(ga))
> +#define mfn_to_maddr(mfn)   pfn_to_paddr(mfn_x(mfn))
> +#define maddr_to_mfn(ma)    _mfn(paddr_to_pfn(ma))
> +#define vmap_to_mfn(va)     maddr_to_mfn(virt_to_maddr((vaddr_t)va))

va needs parenthesizing here. Also why vaddr_t here but ...

> +#define vmap_to_page(va)    mfn_to_page(vmap_to_mfn(va))
> +
> +static inline unsigned long __virt_to_maddr(unsigned long va)
> +{
> +    BUG_ON("unimplemented");
> +    return 0;
> +}
> +
> +static inline void *__maddr_to_virt(unsigned long ma)
> +{
> +    BUG_ON("unimplemented");
> +    return NULL;
> +}
> +
> +#define virt_to_maddr(va) __virt_to_maddr((unsigned long)(va))
> +#define maddr_to_virt(pa) __maddr_to_virt((unsigned long)(pa))

... unsigned long here? In fact for __maddr_to_virt() I think there
better wouldn't be any cast, such that the compiler can spot if, by
mistake, a pointer type value was passed in. Or, wait, we can go
yet further (also on x86): There are no uses of __maddr_to_virt()
except here. Hence the symbol isn't needed (anymore?) in the first
place.

> +/* Convert between Xen-heap virtual addresses and machine frame numbers. */
> +#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)))
> +
> +/*
> + * 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)
> +
> +struct page_info
> +{
> +    /* Each frame can be threaded onto a doubly-linked list. */
> +    struct page_list_entry list;
> +
> +    /* Reference count and various PGC_xxx flags and fields. */
> +    unsigned long count_info;
> +
> +    /* Context-dependent fields follow... */
> +    union {
> +        /* Page is in use: ((count_info & PGC_count_mask) != 0). */
> +        struct {
> +            /* Type reference count and various PGT_xxx flags and fields. */
> +            unsigned long type_info;
> +        } inuse;

Blank line here please.

Jan

> +        /* Page is on a free list: ((count_info & PGC_count_mask) == 0). */
> +        union {
> +            struct {
> +                /*
> +                 * Index of the first *possibly* unscrubbed page in the buddy.
> +                 * One more bit than maximum possible order to accommodate
> +                 * INVALID_DIRTY_IDX.
> +                 */
> +#define INVALID_DIRTY_IDX ((1UL << (MAX_ORDER + 1)) - 1)
> +                unsigned long first_dirty:MAX_ORDER + 1;
> +
> +                /* Do TLBs need flushing for safety before next page use? */
> +                bool need_tlbflush:1;
> +
> +#define BUDDY_NOT_SCRUBBING    0
> +#define BUDDY_SCRUBBING        1
> +#define BUDDY_SCRUB_ABORT      2
> +                unsigned long scrub_state:2;
> +            };
> +
> +            unsigned long val;
> +        } free;
> +    } u;
> +
> +    union {
> +        /* Page is in use */
> +        struct {
> +            /* Owner of this page (NULL if page is anonymous). */
> +            struct domain *domain;
> +        } inuse;
> +
> +        /* Page is on a free list. */
> +        struct {
> +            /* Order-size of the free chunk this page is the head of. */
> +            unsigned int order;
> +        } free;
> +    } v;
> +
> +    union {
> +        /*
> +         * Timestamp from 'TLB clock', used to avoid extra safety flushes.
> +         * Only valid for: a) free pages, and b) pages with zero type count
> +         */
> +        uint32_t tlbflush_timestamp;
> +    };
> +};