Re: [Xen-devel] [PATCH RFC 7/9] xen: arm: handle variable p2m levels in apply_p2m_changes

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Wed, Jul 30, 2014 at 7:17 PM, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> As with prervious changes this involves conversion from a linear series of
> lookups into a loop over the levels.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  xen/arch/arm/p2m.c |  178 
> +++++++++++++++++++++++++---------------------------
>  1 file changed, 84 insertions(+), 94 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 557663f..e9938ae 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -15,7 +15,6 @@
>
>  /* First level P2M is 2 consecutive pages */
>  #define P2M_ROOT_ORDER 1
> -#define P2M_ROOT_ENTRIES (LPAE_ENTRIES<<P2M_ROOT_ORDER)
>  #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
>
>  static bool_t p2m_valid(lpae_t pte)
> @@ -115,31 +114,6 @@ void flush_tlb_domain(struct domain *d)
>          p2m_load_VTTBR(current->domain);
>  }
>
> -static int p2m_first_level_index(paddr_t addr)
> -{
> -    /*
> -     * 1st pages are concatenated so zeroeth offset gives us the
> -     * index of the 1st page
> -     */
> -    return zeroeth_table_offset(addr);
> -}
> -
> -/*
> - * Map whichever of the first pages contain addr. The caller should
> - * then use first_table_offset as an index.
> - */
> -static lpae_t *p2m_map_first(struct p2m_domain *p2m, paddr_t addr)
> -{
> -    struct page_info *page;
> -
> -    if ( first_linear_offset(addr) >= P2M_ROOT_ENTRIES )
> -        return NULL;
> -
> -    page = p2m->root + p2m_first_level_index(addr);
> -
> -    return __map_domain_page(page);
> -}
> -
>  /*
>   * Lookup the MFN corresponding to a domain's PFN.
>   *
> @@ -707,14 +681,13 @@ static int apply_p2m_changes(struct domain *d,
>                       int mattr,
>                       p2m_type_t t)
>  {
> -    int rc, ret;
> +    int level, rc, ret;
>      struct p2m_domain *p2m = &d->arch.p2m;
> -    lpae_t *first = NULL, *second = NULL, *third = NULL;
> +    lpae_t *mappings[4] = { NULL, };
>      paddr_t addr;
> -    unsigned long cur_first_page = ~0,
> -                  cur_first_offset = ~0,
> -                  cur_second_offset = ~0;
> -    unsigned long count = 0;
> +    unsigned int cur_root_table = ~0;
> +    unsigned int cur_offset[4] = { ~0, };
> +    unsigned int count = 0;
>      bool_t flush = false;
>      bool_t flush_pt;
>
> @@ -726,9 +699,27 @@ static int apply_p2m_changes(struct domain *d,
>
>      spin_lock(&p2m->lock);
>
> +    if ( P2M_ROOT_PAGES == 1 )
> +    {
> +        /* Static mapping. P2M_ROOT_PAGES > 1 are handled below */
> +        mappings[P2M_ROOT_LEVEL] = __map_domain_page(p2m->root);
> +        {
> +            rc = -EINVAL;

         In case of 48-bit platform in  pa_range_info[] structure in
setup_virt_paging()
function, the root-order is set to 0. So for 48-bit platform P2M_ROOT_PAGES = 1
and hence Dom0 mapping always fails with below log

(XEN) P2M: 48-bit IPA with 48-bit PA
(XEN) P2M: 4 levels with order-0 root, VTCR 0x80053590
(XEN) *** LOADING DOMAIN 0 ***
(XEN) Loading kernel from boot module @ 0000000080080000
(XEN) Allocating 1:1 mappings totalling 128MB for dom0:
(XEN) Allocated 0x000000f0000000-0x000000f8000000 (128MB/128MB, order 15)
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Failed map pages to DOM0: -22
(XEN) ****************************************
(XEN)
(XEN) Reboot in five seconds...

Regards
Vijay

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