From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: gleb@redhat.com
Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Subject: [PATCH v2 15/15] KVM: MMU: use rcu functions to access the pointer
Date: Thu, 5 Sep 2013 18:29:18 +0800 [thread overview]
Message-ID: <1378376958-27252-16-git-send-email-xiaoguangrong@linux.vnet.ibm.com> (raw)
In-Reply-To: <1378376958-27252-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com>
Use rcu_assign_pointer() to update all the pointer in desc
and use rcu_dereference() to lockless read the pointer
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/mmu.c | 46 ++++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f3f17a0..808c2d9 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -927,12 +927,23 @@ static void pte_list_desc_ctor(void *p)
desc->more = NULL;
}
+#define rcu_assign_pte_list(pte_list_p, value) \
+ rcu_assign_pointer(*(unsigned long __rcu **)(pte_list_p), \
+ (unsigned long *)(value))
+
+#define rcu_assign_desc_more(morep, value) \
+ rcu_assign_pointer(*(unsigned long __rcu **)&morep, \
+ (unsigned long *)value)
+
+#define rcu_assign_spte(sptep, value) \
+ rcu_assign_pointer(*(u64 __rcu **)&sptep, (u64 *)value)
+
static void desc_mark_nulls(unsigned long *pte_list, struct pte_list_desc *desc)
{
unsigned long marker;
marker = (unsigned long)pte_list | 1UL;
- desc->more = (struct pte_list_desc *)marker;
+ rcu_assign_desc_more(desc->more, (struct pte_list_desc *)marker);
}
static bool desc_is_a_nulls(struct pte_list_desc *desc)
@@ -989,10 +1000,6 @@ static int count_spte_number(struct pte_list_desc *desc)
return first_free + desc_num * PTE_LIST_EXT;
}
-#define rcu_assign_pte_list(pte_list_p, value) \
- rcu_assign_pointer(*(unsigned long __rcu **)(pte_list_p), \
- (unsigned long *)(value))
-
/*
* Pte mapping structures:
*
@@ -1019,8 +1026,8 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
if (!(*pte_list & 1)) {
rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
desc = mmu_alloc_pte_list_desc(vcpu);
- desc->sptes[0] = (u64 *)*pte_list;
- desc->sptes[1] = spte;
+ rcu_assign_spte(desc->sptes[0], *pte_list);
+ rcu_assign_spte(desc->sptes[1], spte);
desc_mark_nulls(pte_list, desc);
rcu_assign_pte_list(pte_list, (unsigned long)desc | 1);
return 1;
@@ -1033,13 +1040,13 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
if (desc->sptes[PTE_LIST_EXT - 1]) {
struct pte_list_desc *new_desc;
new_desc = mmu_alloc_pte_list_desc(vcpu);
- new_desc->more = desc;
+ rcu_assign_desc_more(new_desc->more, desc);
desc = new_desc;
rcu_assign_pte_list(pte_list, (unsigned long)desc | 1);
}
free_pos = find_first_free(desc);
- desc->sptes[free_pos] = spte;
+ rcu_assign_spte(desc->sptes[free_pos], spte);
return count_spte_number(desc) - 1;
}
@@ -1057,8 +1064,8 @@ pte_list_desc_remove_entry(unsigned long *pte_list,
* Move the entry from the first desc to this position we want
* to remove.
*/
- desc->sptes[i] = first_desc->sptes[last_used];
- first_desc->sptes[last_used] = NULL;
+ rcu_assign_spte(desc->sptes[i], first_desc->sptes[last_used]);
+ rcu_assign_spte(first_desc->sptes[last_used], NULL);
/* No valid entry in this desc, we can free this desc now. */
if (!first_desc->sptes[0]) {
@@ -1070,7 +1077,7 @@ pte_list_desc_remove_entry(unsigned long *pte_list,
WARN_ON(desc_is_a_nulls(next_desc));
mmu_free_pte_list_desc(first_desc);
- *pte_list = (unsigned long)next_desc | 1ul;
+ rcu_assign_pte_list(pte_list, (unsigned long)next_desc | 1ul);
return;
}
@@ -1079,8 +1086,8 @@ pte_list_desc_remove_entry(unsigned long *pte_list,
* then the desc can be freed.
*/
if (!first_desc->sptes[1] && desc_is_a_nulls(first_desc->more)) {
- *pte_list = (unsigned long)first_desc->sptes[0];
- first_desc->sptes[0] = NULL;
+ rcu_assign_pte_list(pte_list, first_desc->sptes[0]);
+ rcu_assign_spte(first_desc->sptes[0], NULL);
mmu_free_pte_list_desc(first_desc);
}
}
@@ -1102,7 +1109,7 @@ static void pte_list_remove(u64 *spte, unsigned long *pte_list)
pr_err("pte_list_remove: %p 1->BUG\n", spte);
BUG();
}
- *pte_list = 0;
+ rcu_assign_pte_list(pte_list, 0);
return;
}
@@ -1174,9 +1181,12 @@ restart:
* used in the rmap when a spte is removed. Otherwise the
* moved entry will be missed.
*/
- for (i = PTE_LIST_EXT - 1; i >= 0; i--)
- if (desc->sptes[i])
- fn(desc->sptes[i]);
+ for (i = PTE_LIST_EXT - 1; i >= 0; i--) {
+ u64 *sptep = rcu_dereference(desc->sptes[i]);
+
+ if (sptep)
+ fn(sptep);
+ }
desc = rcu_dereference(desc->more);
--
1.8.1.4
next prev parent reply other threads:[~2013-09-05 10:29 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-05 10:29 [PATCH v2 00/15] KVM: MMU: locklessly wirte-protect Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 01/15] KVM: MMU: fix the count of spte number Xiao Guangrong
2013-09-08 12:19 ` Gleb Natapov
2013-09-08 13:55 ` Xiao Guangrong
2013-09-08 14:01 ` Gleb Natapov
2013-09-08 14:24 ` Xiao Guangrong
2013-09-08 14:26 ` Gleb Natapov
2013-09-05 10:29 ` [PATCH v2 02/15] KVM: MMU: properly check last spte in fast_page_fault() Xiao Guangrong
2013-09-30 21:23 ` Marcelo Tosatti
2013-10-03 6:16 ` Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 03/15] KVM: MMU: lazily drop large spte Xiao Guangrong
2013-09-30 22:39 ` Marcelo Tosatti
2013-10-03 6:29 ` Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 04/15] KVM: MMU: flush tlb if the spte can be locklessly modified Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 05/15] KVM: MMU: flush tlb out of mmu lock when write-protect the sptes Xiao Guangrong
2013-09-30 23:05 ` Marcelo Tosatti
2013-10-03 6:46 ` Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 06/15] KVM: MMU: update spte and add it into rmap before dirty log Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 07/15] KVM: MMU: redesign the algorithm of pte_list Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 08/15] KVM: MMU: introduce nulls desc Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 09/15] KVM: MMU: introduce pte-list lockless walker Xiao Guangrong
2013-09-08 12:03 ` Xiao Guangrong
2013-09-16 12:42 ` Gleb Natapov
2013-09-16 13:52 ` Xiao Guangrong
2013-09-16 15:04 ` Gleb Natapov
2013-09-05 10:29 ` [PATCH v2 10/15] KVM: MMU: initialize the pointers in pte_list_desc properly Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 11/15] KVM: MMU: reintroduce kvm_mmu_isolate_page() Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 12/15] KVM: MMU: allow locklessly access shadow page table out of vcpu thread Xiao Guangrong
2013-10-08 1:23 ` Marcelo Tosatti
2013-10-08 4:02 ` Xiao Guangrong
2013-10-09 1:56 ` Marcelo Tosatti
2013-10-09 10:45 ` Xiao Guangrong
2013-10-10 1:47 ` Marcelo Tosatti
2013-10-10 12:08 ` Gleb Natapov
2013-10-10 16:42 ` Marcelo Tosatti
2013-10-10 19:16 ` Gleb Natapov
2013-10-10 21:03 ` Marcelo Tosatti
2013-10-11 5:38 ` Gleb Natapov
2013-10-11 20:30 ` Marcelo Tosatti
2013-10-12 5:53 ` Gleb Natapov
2013-10-14 19:29 ` Marcelo Tosatti
2013-10-15 3:57 ` Gleb Natapov
2013-10-15 22:21 ` Marcelo Tosatti
2013-10-16 0:41 ` Xiao Guangrong
2013-10-16 9:12 ` Gleb Natapov
2013-10-16 20:43 ` Marcelo Tosatti
2013-09-05 10:29 ` [PATCH v2 13/15] KVM: MMU: locklessly write-protect the page Xiao Guangrong
2013-09-05 10:29 ` [PATCH v2 14/15] KVM: MMU: clean up spte_write_protect Xiao Guangrong
2013-09-05 10:29 ` Xiao Guangrong [this message]
2013-09-15 10:26 ` [PATCH v2 00/15] KVM: MMU: locklessly wirte-protect Gleb Natapov
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