KVM: MMU: Don't flush shadow when enabling dirty tracking
Instead, drop large mappings, which were the reason we dropped shadow.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f02b8ed..ccacf0b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3538,14 +3538,18 @@
if (!test_bit(slot, sp->slot_bitmap))
continue;
- if (sp->role.level != PT_PAGE_TABLE_LEVEL)
- continue;
-
pt = sp->spt;
- for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+ if (sp->role.level != PT_PAGE_TABLE_LEVEL
+ && is_large_pte(pt[i])) {
+ drop_spte(kvm, &pt[i],
+ shadow_trap_nonpresent_pte);
+ --kvm->stat.lpages;
+ }
/* avoid RMW */
if (is_writable_pte(pt[i]))
update_spte(&pt[i], pt[i] & ~PT_WRITABLE_MASK);
+ }
}
kvm_flush_remote_tlbs(kvm);
}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f29abeb..a3a8f5f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -621,7 +621,7 @@
struct kvm_userspace_memory_region *mem,
int user_alloc)
{
- int r, flush_shadow = 0;
+ int r;
gfn_t base_gfn;
unsigned long npages;
unsigned long i;
@@ -741,8 +741,6 @@
if (kvm_create_dirty_bitmap(&new) < 0)
goto out_free;
/* destroy any largepage mappings for dirty tracking */
- if (old.npages)
- flush_shadow = 1;
}
#else /* not defined CONFIG_S390 */
new.user_alloc = user_alloc;
@@ -813,9 +811,6 @@
kvm_free_physmem_slot(&old, &new);
kfree(old_memslots);
- if (flush_shadow)
- kvm_arch_flush_shadow(kvm);
-
return 0;
out_free: