Re: [Xen-devel] [PATCH v3] x86/dom0: improve PVH initrd and metadata placement

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.03.2020 11:25, Roger Pau Monne wrote:
> Don't assume there's going to be enough space at the tail of the
> loaded kernel and instead try to find a suitable memory area where the
> initrd and metadata can be loaded.
> 
> Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
preferably with, as Andrew suggested, ...

> --- a/xen/arch/x86/hvm/dom0_build.c
> +++ b/xen/arch/x86/hvm/dom0_build.c
> @@ -490,6 +490,45 @@ static int __init pvh_populate_p2m(struct domain *d)
>  #undef MB1_PAGES
>  }
>  
> +static paddr_t find_memory(const struct domain *d, const struct elf_binary 
> *elf,
> +                           size_t size)
> +{
> +    paddr_t kernel_start = (paddr_t)elf->dest_base & PAGE_MASK;
> +    paddr_t kernel_end = ROUNDUP((paddr_t)elf->dest_base + elf->dest_size,
> +                                 PAGE_SIZE);
> +    unsigned int i;
> +
> +    /*
> +     * The memory map is sorted and all RAM regions starts and sizes are
> +     * aligned to page boundaries.
> +     */
> +    for ( i = 0; i < d->arch.nr_e820; i++ )
> +    {
> +        paddr_t start, end = d->arch.e820[i].addr + d->arch.e820[i].size;
> +
> +        /* Don't use memory below 1MB, as it could overwrite the BDA/EBDA. */

... IBFT added here (I'm not worried so much about whether BDA remains
here or gets dropped). This could of course be done while committing.

Jan

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