KVM: MMU: abstract spte write-protect
Introduce a common function to abstract spte write-protect to
cleanup the code
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5dd2242..d04d630 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1050,36 +1050,48 @@
rmap_remove(kvm, sptep);
}
+/* Return true if the spte is dropped. */
+static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush)
+{
+ u64 spte = *sptep;
+
+ if (!is_writable_pte(spte))
+ return false;
+
+ rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);
+
+ *flush |= true;
+ if (is_large_pte(spte)) {
+ WARN_ON(page_header(__pa(sptep))->role.level ==
+ PT_PAGE_TABLE_LEVEL);
+ drop_spte(kvm, sptep);
+ --kvm->stat.lpages;
+ return true;
+ }
+
+ spte = spte & ~PT_WRITABLE_MASK;
+ mmu_spte_update(sptep, spte);
+ return false;
+}
+
static bool
__rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level)
{
u64 *sptep;
struct rmap_iterator iter;
- bool write_protected = false;
+ bool flush = false;
for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
BUG_ON(!(*sptep & PT_PRESENT_MASK));
- rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);
-
- if (!is_writable_pte(*sptep)) {
- sptep = rmap_get_next(&iter);
+ if (spte_write_protect(kvm, sptep, &flush)) {
+ sptep = rmap_get_first(*rmapp, &iter);
continue;
}
- if (level == PT_PAGE_TABLE_LEVEL) {
- mmu_spte_update(sptep, *sptep & ~PT_WRITABLE_MASK);
- sptep = rmap_get_next(&iter);
- } else {
- BUG_ON(!is_large_pte(*sptep));
- drop_spte(kvm, sptep);
- --kvm->stat.lpages;
- sptep = rmap_get_first(*rmapp, &iter);
- }
-
- write_protected = true;
+ sptep = rmap_get_next(&iter);
}
- return write_protected;
+ return flush;
}
/**
@@ -3886,6 +3898,7 @@
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
{
struct kvm_mmu_page *sp;
+ bool flush = false;
list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
int i;
@@ -3900,16 +3913,7 @@
!is_last_spte(pt[i], sp->role.level))
continue;
- if (is_large_pte(pt[i])) {
- drop_spte(kvm, &pt[i]);
- --kvm->stat.lpages;
- continue;
- }
-
- /* avoid RMW */
- if (is_writable_pte(pt[i]))
- mmu_spte_update(&pt[i],
- pt[i] & ~PT_WRITABLE_MASK);
+ spte_write_protect(kvm, &pt[i], &flush);
}
}
kvm_flush_remote_tlbs(kvm);
