Re: [Xen-devel] [PATCH for-next 09/16] xen/arm: domain_build: Rework initrd_load to use the generic copy helper

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 23 Nov 2017, Julien Grall wrote:
> The function initrd_load is dealing with IPA but uses gvirt_to_maddr to
> do the translation. This is currently working fine because the stage-1 MMU
> is disabled.
> 
> Furthermore, the function is implementing its own copy to guest resulting
> in code duplication and making more difficult to update the logic in
> page-tables (such support for Populate On Demand).
> 
> The new copy_to_guest_phys_flush_dcache could be used here by temporarily
> mapping the full initrd in the virtual space.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>  xen/arch/arm/domain_build.c | 31 ++++++++-----------------------
>  1 file changed, 8 insertions(+), 23 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 3f87bf2051..42c2e16ef6 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -1966,11 +1966,11 @@ static void initrd_load(struct kernel_info *kinfo)
>      const struct bootmodule *mod = kinfo->initrd_bootmodule;
>      paddr_t load_addr = kinfo->initrd_paddr;
>      paddr_t paddr, len;
> -    unsigned long offs;
>      int node;
>      int res;
>      __be32 val[2];
>      __be32 *cellp;
> +    void __iomem *initrd;
>  
>      if ( !mod || !mod->size )
>          return;
> @@ -2000,29 +2000,14 @@ static void initrd_load(struct kernel_info *kinfo)
>      if ( res )
>          panic("Cannot fix up \"linux,initrd-end\" property");
>  
> -    for ( offs = 0; offs < len; )
> -    {
> -        uint64_t par;
> -        paddr_t s, l, ma = 0;
> -        void *dst;
> -
> -        s = offs & ~PAGE_MASK;
> -        l = min(PAGE_SIZE - s, len);
> -
> -        par = gvirt_to_maddr(load_addr + offs, &ma, GV2M_WRITE);
> -        if ( par )
> -        {
> -            panic("Unable to translate guest address");
> -            return;
> -        }
> -
> -        dst = map_domain_page(maddr_to_mfn(ma));
> +    initrd = ioremap_wc(paddr, len);
> +    if ( !initrd )
> +        panic("Unable to map the hwdom initrd");
>  
> -        copy_from_paddr(dst + s, paddr + offs, l);
> -
> -        unmap_domain_page(dst);
> -        offs += l;
> -    }
> +    res = copy_to_guest_phys_flush_dcache(kinfo->d, load_addr,
> +                                          initrd, len);
> +    if ( res != 0 )
> +        panic("Unable to copy the initrd in the hwdom memory");
>  }
>  
>  static void evtchn_fixup(struct domain *d, struct kernel_info *kinfo)

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