Re: [Xen-devel] [PATCH 4/8] xen/vmap: allow vm_init_type to be called during early_boot

[Julien Grall <julien@xxxxxxx>]

Hi David,

On 01/02/2020 01:32, David Woodhouse wrote:
> From: Wei Liu <wei.liu2@xxxxxxxxxx>
>
> We want to move vm_init, which calls vm_init_type under the hood, to
> early boot stage. Add a path to get page from boot allocator instead.
>
> Add an emacs block to that file while I was there.
>
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> ---
>   xen/common/vmap.c | 22 +++++++++++++++++++---
>   1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/xen/common/vmap.c b/xen/common/vmap.c
> index faebc1ddf1..37922f735b 100644
> --- a/xen/common/vmap.c
> +++ b/xen/common/vmap.c
> @@ -34,9 +34,15 @@ void __init vm_init_type(enum vmap_region type, void *start, 
> void *end)
>   
>       for ( i = 0, va = (unsigned long)vm_bitmap(type); i < nr; ++i, va += PAGE_SIZE )
>       {
> -        struct page_info *pg = alloc_domheap_page(NULL, 0);
> -
> -        map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
> +        mfn_t mfn;
> +        int rc;
> +
> +        if ( system_state == SYS_STATE_early_boot )
> +            mfn = alloc_boot_pages(1, 1);
> +        else
> +            mfn = page_to_mfn(alloc_domheap_page(NULL, 0));
It looks like the function was doing a pretty bad job at checking the 
return values :(.
As you add a check for map_pages_to_xen(), would you mind to add another 
one for alloc_domheap_page()?
Other than that, the code looks good to me.

> +        rc = map_pages_to_xen(va, mfn, 1, PAGE_HYPERVISOR);
> +        BUG_ON(rc);
>           clear_page((void *)va);
>       }
>       bitmap_fill(vm_bitmap(type), vm_low[type]);
> @@ -330,3 +336,13 @@ void vfree(void *va)
>           free_domheap_page(pg);
>   }
>   #endif
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
Cheers,

--
Julien Grall

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