Re: [PATCH] x86/HVM: clean up HVMOP_set_mem_type processing

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 30/04/14 14:47, Jan Beulich wrote:
> - drop unused variable "mfn"
> - consistently do not use "else" when the prior "if" ends in "goto"
> - use printk() referencing the target domain instead of gdprintk()
>   (which references the current domain) and slightly shorten message
> - annotate -EINVAL results in paging/shared paths to actually need
>   switching to -EAGAIN (possible only when preemption logic got fixed
>   to use -ERESTART)
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4522,21 +4522,20 @@ long do_hvm_op(unsigned long op, XEN_GUE
>          while ( a.nr > start_iter )
>          {
>              unsigned long pfn = a.first_pfn + start_iter;
> -            p2m_type_t t;
> -            p2m_type_t nt;
> -            mfn_t mfn;
> -            mfn = get_gfn_unshare(d, pfn, &t);
> +            p2m_type_t t, nt;
> +
> +            get_gfn_unshare(d, pfn, &t);
>              if ( p2m_is_paging(t) )
>              {
>                  put_gfn(d, pfn);
>                  p2m_mem_paging_populate(d, pfn);
> -                rc = -EINVAL;
> +                rc = -EINVAL; /* XXX EAGAIN */
>                  goto param_fail4;
>              }
>              if ( p2m_is_shared(t) )
>              {
>                  put_gfn(d, pfn);
> -                rc = -EINVAL;
> +                rc = -EINVAL; /* XXX EAGAIN */
>                  goto param_fail4;
>              } 

Could you nuke the trailing piece of whitespace on this brace as this is
a cleanup patch and it is within-context.

>              if ( !p2m_is_ram(t) &&
> @@ -4545,18 +4544,14 @@ long do_hvm_op(unsigned long op, XEN_GUE
>                  put_gfn(d, pfn);
>                  goto param_fail4;
>              }
> -            else

I know this is inconsistently applied, but a line before setting nt
would look neater.

> +            nt = p2m_change_type(d, pfn, t, memtype[a.hvmmem_type]);
> +            if ( nt != t )
>              {
> -                nt = p2m_change_type(d, pfn, t, memtype[a.hvmmem_type]);
> -                if ( nt != t )
> -                {
> -                    put_gfn(d, pfn);
> -                    gdprintk(XENLOG_WARNING,
> -                             "type of pfn %#lx changed from %d to %d while "
> -                             "we were trying to change it to %d\n",
> -                             pfn, t, nt, memtype[a.hvmmem_type]);
> -                    goto param_fail4;
> -                }
> +                put_gfn(d, pfn);
> +                printk(XENLOG_G_WARNING
> +                       "d%d: GFN %#lx type changed from %d to %d while trying to change it to %d\n",
> +                       d->domain_id, pfn, t, nt, memtype[a.hvmmem_type]);
> +                goto param_fail4;
>              }
>              put_gfn(d, pfn);
>  

Other than those two nits,  content wise

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>