debuggers.hg

changeset 19670:b0966b6f5180

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x86-64: also handle virtual aliases of Xen image pages

With the unification of the heaps, the pages freed from the Xen boot
image now can also end up being allocated to a domain, and hence the
respective aliases need handling when such pages get their
cacheability attributes changed.

Rather than establishing multiple mappings with non-WB attributes
(which temporarily still can cause aliasing issues), simply unmap
those pages from the Xen virtual space, and re-map them (to allow re-
establishing of eventual large page mappings) when the cachability
attribute for them gets restored to normal (WB).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Wed May 20 15:38:34 2009 +0100 (2009-05-20)
parents cafab2084410
children 89e50c449307
files xen/arch/x86/mm.c
line diff
     1.1 --- a/xen/arch/x86/mm.c	Wed May 20 15:35:32 2009 +0100
     1.2 +++ b/xen/arch/x86/mm.c	Wed May 20 15:38:34 2009 +0100
     1.3 @@ -709,6 +709,23 @@ int is_iomem_page(unsigned long mfn)
     1.4      return (page_get_owner(page) == dom_io);
     1.5  }
     1.6  
     1.7 +static void update_xen_mappings(unsigned long mfn, unsigned long cacheattr)
     1.8 +{
     1.9 +#ifdef __x86_64__
    1.10 +    bool_t alias = mfn >= PFN_DOWN(xen_phys_start) &&
    1.11 +         mfn < PFN_UP(xen_phys_start + (unsigned long)_end - XEN_VIRT_START);
    1.12 +    unsigned long xen_va =
    1.13 +        XEN_VIRT_START + ((mfn - PFN_DOWN(xen_phys_start)) << PAGE_SHIFT);
    1.14 +
    1.15 +    if ( unlikely(alias) && cacheattr )
    1.16 +        map_pages_to_xen(xen_va, mfn, 1, 0);
    1.17 +    map_pages_to_xen((unsigned long)mfn_to_virt(mfn), mfn, 1,
    1.18 +                     PAGE_HYPERVISOR | cacheattr_to_pte_flags(cacheattr));
    1.19 +    if ( unlikely(alias) && !cacheattr )
    1.20 +        map_pages_to_xen(xen_va, mfn, 1, PAGE_HYPERVISOR);
    1.21 +#endif
    1.22 +}
    1.23 +
    1.24  
    1.25  int
    1.26  get_page_from_l1e(
    1.27 @@ -796,10 +813,7 @@ get_page_from_l1e(
    1.28              y  = cmpxchg(&page->count_info, x, nx);
    1.29          }
    1.30  
    1.31 -#ifdef __x86_64__
    1.32 -        map_pages_to_xen((unsigned long)mfn_to_virt(mfn), mfn, 1,
    1.33 -                         PAGE_HYPERVISOR | cacheattr_to_pte_flags(cacheattr));
    1.34 -#endif
    1.35 +        update_xen_mappings(mfn, cacheattr);
    1.36      }
    1.37  
    1.38      return 1;
    1.39 @@ -857,12 +871,6 @@ get_page_from_l2e(
    1.40                  return -EINVAL;
    1.41              }
    1.42          } while ( m++ < (mfn + (L1_PAGETABLE_ENTRIES-1)) );
    1.43 -
    1.44 -#ifdef __x86_64__
    1.45 -        map_pages_to_xen(
    1.46 -            (unsigned long)mfn_to_virt(mfn), mfn, L1_PAGETABLE_ENTRIES,
    1.47 -            PAGE_HYPERVISOR | l2e_get_flags(l2e));
    1.48 -#endif
    1.49      }
    1.50  
    1.51      return rc;
    1.52 @@ -2406,10 +2414,7 @@ void cleanup_page_cacheattr(struct page_
    1.53  
    1.54      BUG_ON(is_xen_heap_page(page));
    1.55  
    1.56 -#ifdef __x86_64__
    1.57 -    map_pages_to_xen((unsigned long)page_to_virt(page), page_to_mfn(page),
    1.58 -                     1, PAGE_HYPERVISOR);
    1.59 -#endif
    1.60 +    update_xen_mappings(page_to_mfn(page), 0);
    1.61  }
    1.62  
    1.63