svn commit: r255683 - projects/bhyve_npt_pmap/sys/amd64/amd64

[Neel Natu]

Author: neel
Date: Thu Sep 19 01:12:59 2013
New Revision: 255683
URL: http://svnweb.freebsd.org/changeset/base/255683

Log:
  For a  nested pmap make sure that its 'pm_cr3' is invalid and thus is
  guaranteed to trigger an exception if loaded into the host's %cr3.
  
  Requested by:	kib@

Modified:
  projects/bhyve_npt_pmap/sys/amd64/amd64/pmap.c

Modified: projects/bhyve_npt_pmap/sys/amd64/amd64/pmap.c
==============================================================================
--- projects/bhyve_npt_pmap/sys/amd64/amd64/pmap.c	Thu Sep 19 00:32:07 2013	(r255682)
+++ projects/bhyve_npt_pmap/sys/amd64/amd64/pmap.c	Thu Sep 19 01:12:59 2013	(r255683)
@@ -2139,6 +2139,7 @@ pmap_pinit_type(pmap_t pmap, enum pmap_t
 {
 	vm_page_t pml4pg;
 	pt_entry_t PG_A, PG_M;
+	vm_paddr_t pml4phys;
 	int i;
 
 	/*
@@ -2148,9 +2149,10 @@ pmap_pinit_type(pmap_t pmap, enum pmap_t
 	    VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO)) == NULL)
 		VM_WAIT;
 
-	pmap->pm_cr3 = VM_PAGE_TO_PHYS(pml4pg);
-	pmap->pm_pml4 = (pml4_entry_t *)PHYS_TO_DMAP(pmap->pm_cr3);
+	pml4phys = VM_PAGE_TO_PHYS(pml4pg);
+	pmap->pm_pml4 = (pml4_entry_t *)PHYS_TO_DMAP(pml4phys);
 	pmap->pm_pcid = -1;
+	pmap->pm_cr3 = ~0;	/* initialize to an invalid value */
 
 	if ((pml4pg->flags & PG_ZERO) == 0)
 		pagezero(pmap->pm_pml4);
@@ -2164,6 +2166,8 @@ pmap_pinit_type(pmap_t pmap, enum pmap_t
 		PG_A = pmap_accessed_bit(pmap);
 		PG_M = pmap_modified_bit(pmap);
 
+		pmap->pm_cr3 = pml4phys;
+
 		/* Wire in kernel global address entries. */
 		for (i = 0; i < NKPML4E; i++) {
 			pmap->pm_pml4[KPML4BASE + i] = (KPDPphys + ptoa(i)) |