On Sun, Jan 15, 2012 at 04:48:31PM +0000, Cherry G. Mathew wrote: > Module Name: src > Committed By: cherry > Date: Sun Jan 15 16:48:31 UTC 2012 > > Modified Files: > src/sys/arch/amd64/include: pmap.h > > Log Message: > for xen on amd64 PDP_BASE points to the per-cpu ci->ci_kpm_pdir copy of > *pmap_kernel()*'s L4 pdir, which is an alias for ci->ci_kpm_pdir. This is > unlike PAE, where PDP_BASE points to the per-pmap pm_pdir consisting of 4 > pages, the last of which is the "shadow". This "shadow" is not used directly > in an active pmap, since it duplicates the kernel space and, for PAE, xen > dissallows multiple cpus pointing to the same L3[3] page. Therefore, we use > a per-cpu copy of the pmap_kernel() pdir's L3[3] page, > ci->ci_pae_l3_pdir[3], while L3[0-2] point to the original pmap's pm_pdir[0 > - 2]. Thus the "shadow" pdir only exists on i386 PAE. Note that on PAE, the > recursive PDIR_SLOT_PTE is not per-cpu, and therefore cannot be made to > point to per-cpu pdirs via (L4_BASE + PDIR_SLOT_PTE), unlike xen x86_64 > where this is exactly the case.
in the future please word-wrap your commit messages... -- David A. Holland dholl...@netbsd.org
