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[src/trunk]: src/sys/arch/x86 - pmap_enter(): Remove cosmetic differences bet...
details: https://anonhg.NetBSD.org/src/rev/06380ea22869
branches: trunk
changeset: 745898:06380ea22869
user: ad <ad%NetBSD.org@localhost>
date: Sun Mar 15 15:58:24 2020 +0000
description:
- pmap_enter(): Remove cosmetic differences between the EPT & native cases.
Remove old code to free PVEs that should not be there that caused panics
(merge error moving between source trees on my part).
- pmap_destroy(): pmap_remove_all() doesn't work for EPT yet, so need to catch
up on deferred PTP frees manually in the EPT case.
- pp_embedded: Remove it. It's one more variable to go wrong and another
store to be made. Just check for non-zero PTP pointer & non-zero VA
instead.
diffstat:
sys/arch/x86/include/pmap_pv.h | 4 +-
sys/arch/x86/x86/pmap.c | 89 ++++++++++++++++++++++++-----------------
2 files changed, 53 insertions(+), 40 deletions(-)
diffs (269 lines):
diff -r d2108aad5fd0 -r 06380ea22869 sys/arch/x86/include/pmap_pv.h
--- a/sys/arch/x86/include/pmap_pv.h Sun Mar 15 15:14:22 2020 +0000
+++ b/sys/arch/x86/include/pmap_pv.h Sun Mar 15 15:58:24 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap_pv.h,v 1.14 2020/03/14 18:24:10 ad Exp $ */
+/* $NetBSD: pmap_pv.h,v 1.15 2020/03/15 15:58:24 ad Exp $ */
/*-
* Copyright (c)2008 YAMAMOTO Takashi,
@@ -79,7 +79,6 @@
struct {
struct pv_pte pte;
LIST_HEAD(, pv_entry) pvlist;
- uint8_t embedded;
uint8_t attrs;
} s;
} pp_u;
@@ -88,7 +87,6 @@
#define pp_link pp_u.link
#define pp_pte pp_u.s.pte
#define pp_pvlist pp_u.s.pvlist
-#define pp_embedded pp_u.s.embedded
#define pp_attrs pp_u.s.attrs
};
diff -r d2108aad5fd0 -r 06380ea22869 sys/arch/x86/x86/pmap.c
--- a/sys/arch/x86/x86/pmap.c Sun Mar 15 15:14:22 2020 +0000
+++ b/sys/arch/x86/x86/pmap.c Sun Mar 15 15:58:24 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.368 2020/03/15 15:14:22 ad Exp $ */
+/* $NetBSD: pmap.c,v 1.369 2020/03/15 15:58:24 ad Exp $ */
/*
* Copyright (c) 2008, 2010, 2016, 2017, 2019, 2020 The NetBSD Foundation, Inc.
@@ -130,7 +130,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.368 2020/03/15 15:14:22 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.369 2020/03/15 15:58:24 ad Exp $");
#include "opt_user_ldt.h"
#include "opt_lockdebug.h"
@@ -539,6 +539,17 @@
}
/*
+ * Return true if the pmap page has an embedded PV entry.
+ */
+static inline bool
+pv_pte_embedded(struct pmap_page *pp)
+{
+
+ KASSERT(mutex_owned(&pp->pp_lock));
+ return (bool)((vaddr_t)pp->pp_pte.pte_ptp | pp->pp_pte.pte_va);
+}
+
+/*
* pv_pte_first, pv_pte_next: PV list iterator.
*/
static struct pv_pte *
@@ -546,7 +557,7 @@
{
KASSERT(mutex_owned(&pp->pp_lock));
- if (pp->pp_embedded) {
+ if (pv_pte_embedded(pp)) {
return &pp->pp_pte;
}
return pve_to_pvpte(LIST_FIRST(&pp->pp_pvlist));
@@ -2025,8 +2036,7 @@
* set together for this pmap.
*
*/
- if (atomic_load_relaxed(&old_pp->pp_embedded) &&
- atomic_load_relaxed(&old_pp->pp_pte.pte_ptp) == ptp &&
+ if (atomic_load_relaxed(&old_pp->pp_pte.pte_ptp) == ptp &&
atomic_load_relaxed(&old_pp->pp_pte.pte_va) == va) {
return NULL;
}
@@ -2080,8 +2090,7 @@
* to check for this very specific set of values without a lock
* because all 3 will only ever be set together for this pmap.
*/
- if (atomic_load_relaxed(&pp->pp_embedded) &&
- atomic_load_relaxed(&pp->pp_pte.pte_ptp) == ptp &&
+ if (atomic_load_relaxed(&pp->pp_pte.pte_ptp) == ptp &&
atomic_load_relaxed(&pp->pp_pte.pte_va) == va) {
*samepage = true;
return 0;
@@ -2108,13 +2117,12 @@
error = 0;
mutex_spin_enter(&pp->pp_lock);
- if (!pp->pp_embedded) {
+ if (!pv_pte_embedded(pp)) {
/*
* Embedded PV tracking available - easy.
*/
pp->pp_pte.pte_ptp = ptp;
pp->pp_pte.pte_va = va;
- pp->pp_embedded = true;
*new_embedded = true;
} else if (__predict_false(pmap->pm_pve == NULL)) {
/*
@@ -2160,14 +2168,10 @@
mutex_spin_enter(&pp->pp_lock);
pp->pp_attrs |= oattrs;
if (pve == NULL) {
- KASSERT(pp->pp_embedded);
KASSERT(pp->pp_pte.pte_ptp == ptp);
KASSERT(pp->pp_pte.pte_va == va);
- pp->pp_embedded = false;
-#ifdef DIAGNOSTIC
pp->pp_pte.pte_ptp = NULL;
pp->pp_pte.pte_va = 0;
-#endif
mutex_spin_exit(&pp->pp_lock);
} else {
KASSERT(pve == pmap_lookup_pv(pmap, ptp, pp, va));
@@ -2786,16 +2790,24 @@
int i;
/*
- * drop reference count
+ * drop reference count and verify not in use.
*/
if (atomic_dec_uint_nv(&pmap->pm_obj[0].uo_refs) > 0) {
return;
}
-
pmap_check_inuse(pmap);
/*
+ * XXX handle deferred PTP page free for EPT. ordinarily this is
+ * taken care of by pmap_remove_all(). once shared with EPT this
+ * can go away.
+ */
+ if (__predict_false(!LIST_EMPTY(&pmap->pm_gc_ptp))) {
+ pmap_update(pmap);
+ }
+
+ /*
* Reference count is zero, free pmap resources and then free pmap.
*/
@@ -4105,9 +4117,12 @@
/*
* Do an unlocked check to see if the page has no mappings, eg when
* pmap_remove_all() was called before amap_wipeout() for a process
- * private amap - common.
+ * private amap - common. The page being removed must be on the way
+ * out, so we don't have to worry about concurrent attempts to enter
+ * it (otherwise the caller either doesn't care or has screwed up).
*/
- if (atomic_load_relaxed(&pp->pp_embedded) == 0 &&
+ if (atomic_load_relaxed(&pp->pp_pte.pte_va) == 0 &&
+ atomic_load_relaxed(&pp->pp_pte.pte_ptp) == NULL &&
atomic_load_relaxed(&pp->pp_pvlist.lh_first) == NULL) {
return;
}
@@ -4554,10 +4569,10 @@
struct vm_page *new_pg, *old_pg;
struct pmap_page *new_pp, *old_pp;
struct pv_entry *old_pve, *new_pve;
- int error;
bool wired = (flags & PMAP_WIRED) != 0;
struct pmap *pmap2;
struct pmap_ptparray pt;
+ int error;
bool getptp, samepage, new_embedded;
rb_tree_t *tree;
@@ -4631,6 +4646,8 @@
pmap_ptp_range_set(ptp, va);
tree = &VM_PAGE_TO_PP(ptp)->pp_rb;
} else {
+ /* Embedded PV entries rely on this. */
+ KASSERT(va != 0);
tree = &pmap_kernel_rb;
}
@@ -4716,7 +4733,8 @@
KASSERT(pmap->pm_pve == NULL);
pmap->pm_pve = new_pve;
} else if (new_embedded) {
- new_pp->pp_embedded = false;
+ new_pp->pp_pte.pte_ptp = NULL;
+ new_pp->pp_pte.pte_va = 0;
}
mutex_spin_exit(&new_pp->pp_lock);
pmap_unmap_ptes(pmap, pmap2);
@@ -5139,7 +5157,8 @@
pp = VM_PAGE_TO_PP(ptp);
LIST_INIT(&pp->pp_pvlist);
pp->pp_attrs = 0;
- pp->pp_embedded = false;
+ pp->pp_pte.pte_ptp = NULL;
+ pp->pp_pte.pte_va = 0;
/*
* XXX Hack to avoid extra locking, and lock
@@ -5548,6 +5567,8 @@
pmap_ptp_range_set(ptp, va);
tree = &VM_PAGE_TO_PP(ptp)->pp_rb;
} else {
+ /* Embedded PV entries rely on this. */
+ KASSERT(va != 0);
tree = &pmap_kernel_rb;
}
@@ -5595,12 +5616,7 @@
pmap_ept_install_ptp(pmap, &pt, va);
}
- /*
- * Check if there is an existing mapping. If we are now sure that
- * we need pves and we failed to allocate them earlier, handle that.
- * Caching the value of oldpa here is safe because only the mod/ref
- * bits can change while the pmap is locked.
- */
+ /* Check if there is an existing mapping. */
ptes = (pt_entry_t *)PMAP_DIRECT_MAP(VM_PAGE_TO_PHYS(ptp));
ptep = &ptes[pl1_pi(va)];
opte = *ptep;
@@ -5622,6 +5638,11 @@
} while (pmap_pte_cas(ptep, opte, npte) != opte);
/*
+ * Done with the PTEs: they can now be unmapped.
+ */
+ kpreempt_enable();
+
+ /*
* Update statistics and PTP's reference count.
*/
pmap_ept_stats_update_bypte(pmap, npte, opte);
@@ -5673,6 +5694,10 @@
}
same_pa:
+ /*
+ * shootdown tlb if necessary.
+ */
+
if (pmap_ept_has_ad) {
accessed = (~opte & (EPT_R | EPT_A)) == 0;
} else {
@@ -5681,18 +5706,8 @@
if (accessed && ((opte ^ npte) & (PTE_FRAME | EPT_W)) != 0) {
pmap_tlb_shootdown(pmap, va, 0, TLBSHOOT_ENTER);
}
-
- error = 0;
- kpreempt_enable();
- if (old_pve != NULL) {
- pool_cache_put(&pmap_pv_cache, old_pve);
- }
- if (new_pve != NULL) {
- pool_cache_put(&pmap_pv_cache, new_pve);
- }
mutex_exit(&pmap->pm_lock);
-
- return error;
+ return 0;
}
/* Pay close attention, this returns L2. */
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