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Diffstat (limited to 'drivers/kvm')
-rw-r--r--drivers/kvm/paging_tmpl.h36
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 3c40a598ceb..8086f827120 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -34,7 +34,9 @@
#define PT_LEVEL_BITS PT64_LEVEL_BITS
#ifdef CONFIG_X86_64
#define PT_MAX_FULL_LEVELS 4
+ #define CMPXCHG cmpxchg
#else
+ #define CMPXCHG cmpxchg64
#define PT_MAX_FULL_LEVELS 2
#endif
#elif PTTYPE == 32
@@ -48,6 +50,7 @@
#define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
#define PT_LEVEL_BITS PT32_LEVEL_BITS
#define PT_MAX_FULL_LEVELS 2
+ #define CMPXCHG cmpxchg
#else
#error Invalid PTTYPE value
#endif
@@ -78,6 +81,26 @@ static gfn_t gpte_to_gfn_pde(pt_element_t gpte)
return (gpte & PT_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
}
+static bool FNAME(cmpxchg_gpte)(struct kvm *kvm,
+ gfn_t table_gfn, unsigned index,
+ pt_element_t orig_pte, pt_element_t new_pte)
+{
+ pt_element_t ret;
+ pt_element_t *table;
+ struct page *page;
+
+ page = gfn_to_page(kvm, table_gfn);
+ table = kmap_atomic(page, KM_USER0);
+
+ ret = CMPXCHG(&table[index], orig_pte, new_pte);
+
+ kunmap_atomic(table, KM_USER0);
+
+ kvm_release_page_dirty(page);
+
+ return (ret != orig_pte);
+}
+
/*
* Fetch a guest pte for a guest virtual address
*/
@@ -91,6 +114,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
gpa_t pte_gpa;
pgprintk("%s: addr %lx\n", __FUNCTION__, addr);
+walk:
walker->level = vcpu->mmu.root_level;
pte = vcpu->cr3;
#if PTTYPE == 64
@@ -135,8 +159,10 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
if (!(pte & PT_ACCESSED_MASK)) {
mark_page_dirty(vcpu->kvm, table_gfn);
+ if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn,
+ index, pte, pte|PT_ACCESSED_MASK))
+ goto walk;
pte |= PT_ACCESSED_MASK;
- kvm_write_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte));
}
if (walker->level == PT_PAGE_TABLE_LEVEL) {
@@ -159,9 +185,14 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
}
if (write_fault && !is_dirty_pte(pte)) {
+ bool ret;
+
mark_page_dirty(vcpu->kvm, table_gfn);
+ ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte,
+ pte|PT_DIRTY_MASK);
+ if (ret)
+ goto walk;
pte |= PT_DIRTY_MASK;
- kvm_write_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte));
kvm_mmu_pte_write(vcpu, pte_gpa, (u8 *)&pte, sizeof(pte));
}
@@ -484,3 +515,4 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
#undef PT_MAX_FULL_LEVELS
#undef gpte_to_gfn
#undef gpte_to_gfn_pde
+#undef CMPXCHG