svn commit: r268478 - in projects/amd64_xen_pv/sys/amd64: include/xen xen

[Cherry G. Mathew]

Author: cherry
Date: Thu Jul 10 02:15:16 2014
New Revision: 268478
URL: http://svnweb.freebsd.org/changeset/base/268478

Log:
  Clear aliased user pagetables in kernel VA space before trying to
  destroy the user pmap.
  
  Kernel now boots to single user mode, with 4K backed pages and direct
  mapped physical memory.
  
  Approved by:	gibbs(implicit)

Modified:
  projects/amd64_xen_pv/sys/amd64/include/xen/xenpmap.h
  projects/amd64_xen_pv/sys/amd64/xen/pmap.c

Modified: projects/amd64_xen_pv/sys/amd64/include/xen/xenpmap.h
==============================================================================
--- projects/amd64_xen_pv/sys/amd64/include/xen/xenpmap.h	Thu Jul 10 00:15:55 2014	(r268477)
+++ projects/amd64_xen_pv/sys/amd64/include/xen/xenpmap.h	Thu Jul 10 02:15:16 2014	(r268478)
@@ -233,7 +233,12 @@ static inline pt_entry_t pte_load_store(
 	pte = *ptep;
 	
 	pte_store(ptep, npte);
-	/* XXX: SMP race! */
+
+	/* 
+	 * The hypervisor pte write implementation is atomic (see
+	 * xen/include/asm-x86/x86_64/page.h) so our saved value is
+	 * consistent.
+	 */
 
 	return pte;
 }

Modified: projects/amd64_xen_pv/sys/amd64/xen/pmap.c
==============================================================================
--- projects/amd64_xen_pv/sys/amd64/xen/pmap.c	Thu Jul 10 00:15:55 2014	(r268477)
+++ projects/amd64_xen_pv/sys/amd64/xen/pmap.c	Thu Jul 10 02:15:16 2014	(r268478)
@@ -1058,26 +1058,6 @@ pmap_xen_bootpages(vm_paddr_t *firstaddr
 }
 
 
-/* alloc from linear mapped boot time virtual address space */
-static uintptr_t
-mmu_alloc(void)
-{
-	uintptr_t va;
-
-	KASSERT(physfree != 0,
-		("physfree must have been set before using mmu_alloc"));
-				
-	va = PTOV(allocpages(&physfree, atop(PAGE_SIZE)));
-
-	/* 
-	 * Xen requires the page table hierarchy to be R/O.
-	 */
-
-	pmap_xen_setpages_ro(va, atop(PAGE_SIZE));
-
-	return va;
-}
-
 void
 pmap_bootstrap(vm_paddr_t *firstaddr)
 {
@@ -2596,7 +2576,16 @@ void pmap_xen_userload(pmap_t pmap)
 	xen_pt_user_switch(pmap->pm_cr3);
 }
 
-
+/* Clear kernel alias to user VA mappings */
+static void pmap_xen_userclear(void)
+{
+	int i;
+	for (i = 0; i < NUPML4E; i++) {
+		PT_CLEAR_VA((pml4_entry_t *)PTOV(KPML4phys) + i, false);
+	}
+	PT_UPDATES_FLUSH();
+	invltlb();
+}
 /*
  * First find and then destroy the pv entry for the specified pmap and virtual
  * address.  This operation can be performed on pv lists for either 4KB or 2MB
@@ -2892,7 +2881,6 @@ retry:
 		 * deallocated.
 		 */
 		mpte = _pmap_allocpte(pmap, pmap_pde_pindex(va), &lock);
-		//panic(__func__);
 		goto retry;
 	} else
 		panic("pmap_enter: invalid page directory va=%#lx", va);
@@ -3982,6 +3970,9 @@ pmap_remove_pages(pmap_t pmap)
 	SLIST_INIT(&free);
 	rw_rlock(&pvh_global_lock);
 	PMAP_LOCK(pmap);
+	/* Kill the Xen user alias mappings, if any */
+	/* XXX: If pmap is current pmap ? */
+	pmap_xen_userclear();
 	TAILQ_FOREACH_SAFE(pc, &pmap->pm_pvchunk, pc_list, npc) {
 		allfree = 1;
 		freed = 0;
@@ -4001,7 +3992,7 @@ pmap_remove_pages(pmap_t pmap)
 				if ((tpte & (PG_PS | PG_V)) == PG_V) {
 					superpage = FALSE;
 					ptepde = tpte;
-					pte = (pt_entry_t *)PHYS_TO_DMAP(tpte &
+					pte = (pt_entry_t *)MACH_TO_DMAP(tpte &
 					    PG_FRAME);
 					pte = &pte[pmap_pte_index(pv->pv_va)];
 					tpte = *pte;