Re: [Xen-devel] [RFC PATCH 6/8]: Ballooning changes

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2012-08-16 at 02:05 +0100, Mukesh Rathor wrote:
> ---
>  drivers/xen/balloon.c |   26 +++++++++++++++++++++-----
>  1 files changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 31ab82f..57960a1 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -358,10 +358,18 @@ static enum bp_state increase_reservation(unsigned long 
> nr_pages)
>               BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
>                      phys_to_machine_mapping_valid(pfn));
>  
> -             set_phys_to_machine(pfn, frame_list[i]);
> -
> +             if (!xen_pvh_domain()) {

XENFEAT_auto_translated...?

> +                     set_phys_to_machine(pfn, frame_list[i]);
> +             } else {
> +                     pte_t *ptep;
> +                     unsigned int level;
> +                     void *addr = __va(pfn << PAGE_SHIFT);
> +                     ptep = lookup_address((unsigned long)addr, &level);
> +                     set_pte(ptep, pfn_pte(pfn, PAGE_KERNEL));
> +             }
>               /* Link back into the page tables if not highmem. */
> -             if (xen_pv_domain() && !PageHighMem(page)) {
> +             if (xen_pv_domain() && !PageHighMem(page) &&
> +                 !xen_pvh_domain()) {

It feels like this ought to be inside the !xen_pvh_domain above as well
as just hte set_phys_to_machine.

And is the else above not missing a !PageHighMem check?

>                       int ret;
>                       ret = HYPERVISOR_update_va_mapping(
>                               (unsigned long)__va(pfn << PAGE_SHIFT),
> @@ -417,7 +425,14 @@ static enum bp_state decrease_reservation(unsigned long 
> nr_pages, gfp_t gfp)
>  
>               scrub_page(page);
>  
> -             if (xen_pv_domain() && !PageHighMem(page)) {
> +             if (xen_pvh_domain() && !PageHighMem(page)) {
> +                     unsigned int level;
> +                     pte_t *ptep;
> +                     void *addr = __va(pfn << PAGE_SHIFT);
> +                     ptep = lookup_address((unsigned long)addr, &level);
> +                     set_pte(ptep, __pte(0));
> +
> +             } else if (xen_pv_domain() && !PageHighMem(page)) {
>                       ret = HYPERVISOR_update_va_mapping(
>                               (unsigned long)__va(pfn << PAGE_SHIFT),
>                               __pte_ma(0), 0);

This pattern:

        if ( xen_pvh_... )
                ... lookup_address / set_pte ...
        else
                ... HYOERVISOR_update_va_mapping

Was present above too -- candidate for a helper? (I was a bit surprised
there wasn't already one...)

> @@ -433,7 +448,8 @@ static enum bp_state decrease_reservation(unsigned long 
> nr_pages, gfp_t gfp)
>       /* No more mappings: invalidate P2M and add to balloon. */
>       for (i = 0; i < nr_pages; i++) {
>               pfn = mfn_to_pfn(frame_list[i]);
> -             __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
> +             if (!xen_pvh_domain())

XENFEAT_something?

> +                     __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
>               balloon_append(pfn_to_page(pfn));
>       }
>  



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