Re: [Xen-devel] [PATCH 08/13] xen: add service function to copy physical memory areas

[Juergen Gross <jgross@xxxxxxxx>]

On 02/19/2015 06:35 PM, David Vrabel wrote:
> On 18/02/2015 06:52, Juergen Gross wrote:
> > In case a pre-allocated memory area is to be moved in order to avoid
> > a conflict with the target E820 map we need a way to copy data between
> > physical addresses.
> >
> > Add a function doing this via early_memremap().
> [...]
> > --- a/arch/x86/xen/setup.c
> > +++ b/arch/x86/xen/setup.c
> > @@ -766,6 +766,35 @@ phys_addr_t __init xen_find_free_area(phys_addr_t
> > size)
> >   }
> >
> >   /*
> > + * Like memcpy, but with physical addresses for dest and src.
> > + */
> > +void __init xen_phys_memcpy(phys_addr_t dest, phys_addr_t src,
> > phys_addr_t n)
> > +{
> > +    phys_addr_t dest_off, src_off, dest_len, src_len, len;
> > +    void *from, *to;
> > +
> > +    while (n) {
> > +        dest_off = dest & ~PAGE_MASK;
> > +        src_off = src & ~PAGE_MASK;
> > +        dest_len = n;
> > +        if (dest_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off)
> > +            dest_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off;
> > +        src_len = n;
> > +        if (src_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off)
> > +            src_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off;
> > +        len = min(dest_len, src_len);
> > +        to = early_memremap(dest - dest_off, dest_len + dest_off);
> > +        from = early_memremap(src - src_off, src_len + src_off);
> > +        memcpy(to, from, len);
> > +        early_iounmap(to, dest_len + dest_off);
> > +        early_iounmap(from, src_len + src_off);
> early_memunmap surely?
Hmm, yes, sure. I'll update the patch and send another one for
correcting the code where I took the usage from (relocate_initrd).

Juergen

> Otherwise,
>
> Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
>
> David
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