Date: Fri, 7 Jan 2011 14:03:28 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r217095 - stable/8/sys/i386/xen Message-ID: <201101071403.p07E3SQZ054518@svn.freebsd.org>
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Author: cperciva Date: Fri Jan 7 14:03:28 2011 New Revision: 217095 URL: http://svn.freebsd.org/changeset/base/217095 Log: MFC r216944,r216963,r216960: Improve the stability of the i386/XEN pmap code by correctly protecting page mapping queue variables within a critical section and by adding ham-fisted locking to pmap.c. Modified: stable/8/sys/i386/xen/pmap.c stable/8/sys/i386/xen/xen_machdep.c Directory Properties: stable/8/sys/ (props changed) stable/8/sys/amd64/include/xen/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) stable/8/sys/contrib/dev/acpica/ (props changed) stable/8/sys/contrib/pf/ (props changed) Modified: stable/8/sys/i386/xen/pmap.c ============================================================================== --- stable/8/sys/i386/xen/pmap.c Fri Jan 7 12:16:17 2011 (r217094) +++ stable/8/sys/i386/xen/pmap.c Fri Jan 7 14:03:28 2011 (r217095) @@ -202,6 +202,11 @@ __FBSDID("$FreeBSD$"); #define pmap_pte_set_prot(pte, v) ((*(int *)pte &= ~PG_PROT), (*(int *)pte |= (v))) +#define HAMFISTED_LOCKING +#ifdef HAMFISTED_LOCKING +static struct mtx createdelete_lock; +#endif + struct pmap kernel_pmap_store; LIST_HEAD(pmaplist, pmap); static struct pmaplist allpmaps; @@ -502,6 +507,10 @@ pmap_bootstrap(vm_paddr_t firstaddr) /* Turn on PG_G on kernel page(s) */ pmap_set_pg(); #endif + +#ifdef HAMFISTED_LOCKING + mtx_init(&createdelete_lock, "pmap create/delete", NULL, MTX_DEF); +#endif } /* @@ -1510,6 +1519,10 @@ pmap_pinit(pmap_t pmap) static int color; int i; +#ifdef HAMFISTED_LOCKING + mtx_lock(&createdelete_lock); +#endif + PMAP_LOCK_INIT(pmap); /* @@ -1521,6 +1534,9 @@ pmap_pinit(pmap_t pmap) NBPTD); if (pmap->pm_pdir == NULL) { PMAP_LOCK_DESTROY(pmap); +#ifdef HAMFISTED_LOCKING + mtx_unlock(&createdelete_lock); +#endif return (0); } #if defined(XEN) && defined(PAE) @@ -1606,6 +1622,9 @@ pmap_pinit(pmap_t pmap) TAILQ_INIT(&pmap->pm_pvchunk); bzero(&pmap->pm_stats, sizeof pmap->pm_stats); +#ifdef HAMFISTED_LOCKING + mtx_unlock(&createdelete_lock); +#endif return (1); } @@ -1841,6 +1860,10 @@ pmap_release(pmap_t pmap) pmap->pm_stats.resident_count)); PT_UPDATES_FLUSH(); +#ifdef HAMFISTED_LOCKING + mtx_lock(&createdelete_lock); +#endif + pmap_lazyfix(pmap); mtx_lock_spin(&allpmaps_lock); LIST_REMOVE(pmap, pm_list); @@ -1876,6 +1899,10 @@ pmap_release(pmap_t pmap) pmap_qremove((vm_offset_t)pmap->pm_pdpt, 1); #endif PMAP_LOCK_DESTROY(pmap); + +#ifdef HAMFISTED_LOCKING + mtx_unlock(&createdelete_lock); +#endif } static int @@ -3242,6 +3269,10 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pm CTR5(KTR_PMAP, "pmap_copy: dst_pmap=%p src_pmap=%p dst_addr=0x%x len=%d src_addr=0x%x", dst_pmap, src_pmap, dst_addr, len, src_addr); +#ifdef HAMFISTED_LOCKING + mtx_lock(&createdelete_lock); +#endif + vm_page_lock_queues(); if (dst_pmap < src_pmap) { PMAP_LOCK(dst_pmap); @@ -3331,6 +3362,10 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pm vm_page_unlock_queues(); PMAP_UNLOCK(src_pmap); PMAP_UNLOCK(dst_pmap); + +#ifdef HAMFISTED_LOCKING + mtx_unlock(&createdelete_lock); +#endif } static __inline void Modified: stable/8/sys/i386/xen/xen_machdep.c ============================================================================== --- stable/8/sys/i386/xen/xen_machdep.c Fri Jan 7 12:16:17 2011 (r217094) +++ stable/8/sys/i386/xen/xen_machdep.c Fri Jan 7 14:03:28 2011 (r217095) @@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$"); #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/kernel.h> +#include <sys/proc.h> #include <sys/reboot.h> #include <sys/sysproto.h> @@ -249,10 +250,12 @@ _xen_flush_queue(void) SET_VCPU(); int _xpq_idx = XPQ_IDX; int error, i; - /* window of vulnerability here? */ +#ifdef INVARIANTS if (__predict_true(gdtset)) - critical_enter(); + CRITICAL_ASSERT(curthread); +#endif + XPQ_IDX = 0; /* Make sure index is cleared first to avoid double updates. */ error = HYPERVISOR_mmu_update((mmu_update_t *)&XPQ_QUEUE, @@ -286,8 +289,6 @@ _xen_flush_queue(void) } } #endif - if (__predict_true(gdtset)) - critical_exit(); if (__predict_false(error < 0)) { for (i = 0; i < _xpq_idx; i++) printf("val: %llx ptr: %llx\n", @@ -301,7 +302,12 @@ void xen_flush_queue(void) { SET_VCPU(); + + if (__predict_true(gdtset)) + critical_enter(); if (XPQ_IDX != 0) _xen_flush_queue(); + if (__predict_true(gdtset)) + critical_exit(); } static __inline void
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