Re: [PATCH v2 04/17] xen/riscv: construct the P2M pages pool for guests

[Jan Beulich <jbeulich@suse.com>]

On 10.06.2025 15:05, Oleksii Kurochko wrote:
> @@ -18,10 +20,20 @@ struct arch_vcpu_io {
>  struct arch_vcpu {
>  };
>  
> +struct paging_domain {
> +    spinlock_t lock;
> +    /* Free P2M pages from the pre-allocated P2M pool */
> +    struct page_list_head p2m_freelist;
> +    /* Number of pages from the pre-allocated P2M pool */
> +    unsigned long p2m_total_pages;
> +};
> +
>  struct arch_domain {
>      struct hvm_domain hvm;
>  
>      struct p2m_domain p2m;
> +
> +    struct paging_domain paging;

With the separate structures, do you have plans to implement e.g. shadow paging?
Or some other paging mode beyond the basic one based on the H extension? If the
structures are to remain separate, may I suggest that you keep things properly
separated (no matter how e.g. Arm may have it) in terms of naming? I.e. no
single "p2m" inside struct paging_domain.

> @@ -105,6 +106,9 @@ int p2m_init(struct domain *d)
>      struct p2m_domain *p2m = p2m_get_hostp2m(d);
>      int rc;
>  
> +    spin_lock_init(&d->arch.paging.lock);
> +    INIT_PAGE_LIST_HEAD(&d->arch.paging.p2m_freelist);

If you want p2m and paging to be separate, you will want to put these in a new
paging_init().

Jan