linux/Documentation/kvm
Lai Jiangshan 2032a93d66 KVM: MMU: Don't allocate gfns page for direct mmu pages
When sp->role.direct is set, sp->gfns does not contain any essential
information, leaf sptes reachable from this sp are for a continuous
guest physical memory range (a linear range).
So sp->gfns[i] (if it was set) equals to sp->gfn + i. (PT_PAGE_TABLE_LEVEL)
Obviously, it is not essential information, we can calculate it when need.

It means we don't need sp->gfns when sp->role.direct=1,
Thus we can save one page usage for every kvm_mmu_page.

Note:
  Access to sp->gfns must be wrapped by kvm_mmu_page_get_gfn()
  or kvm_mmu_page_set_gfn().
  It is only exposed in FNAME(sync_page).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:35:52 +03:00
..
api.txt KVM: Document KVM_SET_BOOT_CPU_ID 2010-08-01 10:35:40 +03:00
cpuid.txt KVM: Add cpuid.txt file 2010-05-19 11:41:07 +03:00
mmu.txt KVM: MMU: Don't allocate gfns page for direct mmu pages 2010-08-01 10:35:52 +03:00