Re: [PATCH 5/6] x86/pv: map and unmap page tables in mark_pv_pt_pages_rdonly

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.04.2020 14:29, Hongyan Xia wrote:
> (Looks like other patches in this series have been merged. Replying to
> this one only.)

Please send as a proper patch, this one came through ...

> From: Wei Liu <wei.liu2@xxxxxxxxxx>
> Date: Tue, 5 Feb 2019 16:32:54 +0000
> Subject: [PATCH] x86/pv: map and unmap page tables in
> mark_pv_pt_pages_rdonly
> 
> Also, clean up the initialisation of plXe.
> 
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx>
> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
> ---
>  xen/arch/x86/pv/dom0_build.c | 32 +++++++++++++++++---------------
>  1 file changed, 17 insertions(+), 15 deletions(-)
> 
> diff --git a/xen/arch/x86/pv/dom0_build.c
> b/xen/arch/x86/pv/dom0_build.c
> index abfbe5f436..3522eb0114 100644
> --- a/xen/arch/x86/pv/dom0_build.c
> +++ b/xen/arch/x86/pv/dom0_build.c
> @@ -49,18 +49,11 @@ static __init void mark_pv_pt_pages_rdonly(struct
> domain *d,
>  {
>      unsigned long count;
>      struct page_info *page;
> -    l4_pgentry_t *pl4e;
> -    l3_pgentry_t *pl3e;
> -    l2_pgentry_t *pl2e;
> -    l1_pgentry_t *pl1e;
> -
> -    pl4e = l4start + l4_table_offset(vpt_start);
> -    pl3e = l4e_to_l3e(*pl4e);
> -    pl3e += l3_table_offset(vpt_start);
> -    pl2e = l3e_to_l2e(*pl3e);
> -    pl2e += l2_table_offset(vpt_start);
> -    pl1e = l2e_to_l1e(*pl2e);
> -    pl1e += l1_table_offset(vpt_start);
> +    l4_pgentry_t *pl4e = l4start + l4_table_offset(vpt_start);
> +    l3_pgentry_t *pl3e = map_l3t_from_l4e(*pl4e) +
> l3_table_offset(vpt_start);
> +    l2_pgentry_t *pl2e = map_l2t_from_l3e(*pl3e) +
> l2_table_offset(vpt_start);
> +    l1_pgentry_t *pl1e = map_l1t_from_l2e(*pl2e) +
> l1_table_offset(vpt_start);

... mangled anyway. I also think with the change made you need to
drop the R-b.

Jan