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

From: Julien Grall <julien@xen.org>
To: David Woodhouse <dwmw2@infradead.org>, xen-devel@lists.xenproject.org
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
	"Wei Liu" <wl@xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"George Dunlap" <George.Dunlap@eu.citrix.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Varad Gautam" <vrd@amazon.de>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"Hongyan Xia" <hongyxia@amazon.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Paul Durrant" <pdurrant@amazon.co.uk>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 4/8] xen/vmap: allow vm_init_type to be called during early_boot
Date: Thu, 13 Feb 2020 11:36:07 +0100	[thread overview]
Message-ID: <c742911e-c2a1-3ade-b675-c16000e728e5@xen.org> (raw)
In-Reply-To: <20200201003303.2363081-4-dwmw2@infradead.org>

Hi David,

On 01/02/2020 01:32, David Woodhouse wrote:
> From: Wei Liu <wei.liu2@citrix.com>
> 
> 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@citrix.com>
> ---
>   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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