[PATCH RFC v2 2/6] KVM: introduce wrapper functions to create and destroy dirty bitmaps

Takuya Yoshikawa
2010-04-20T10:54:09Z

We will change the vmalloc() and vfree() to do_mmap() and do_munmap()
later. This patch makes it easy and cleanup the code.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---
virt/kvm/kvm_main.c | 27 ++++++++++++++++++++-------
1 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cc78e07..40a6888 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -431,6 +431,12 @@ out_err_nodisable:
return ERR_PTR(r);
}

+static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
+{
+ vfree(memslot->dirty_bitmap);
+ memslot->dirty_bitmap = NULL;
+}
+
/*
* Free any memory in @free but not in @dont.
*/
@@ -443,7 +449,7 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
vfree(free->rmap);

if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
- vfree(free->dirty_bitmap);
+ kvm_destroy_dirty_bitmap(free);

for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
@@ -454,7 +460,6 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
}

free->npages = 0;
- free->dirty_bitmap = NULL;
free->rmap = NULL;
}

@@ -516,6 +521,18 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
return 0;
}

+static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
+{
+ unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);
+
+ memslot->dirty_bitmap = vmalloc(dirty_bytes);
+ if (!memslot->dirty_bitmap)
+ return -ENOMEM;
+
+ memset(memslot->dirty_bitmap, 0, dirty_bytes);
+ return 0;
+}
+
/*
* Allocate some memory and give it an address in the guest physical address
* space.
@@ -649,12 +666,8 @@ skip_lpage:

/* Allocate page dirty bitmap if needed */
if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
- unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(&new);
-
- new.dirty_bitmap = vmalloc(dirty_bytes);
- if (!new.dirty_bitmap)
+ if (kvm_create_dirty_bitmap(&new) < 0)
goto out_free;
- memset(new.dirty_bitmap, 0, dirty_bytes);
/* destroy any largepage mappings for dirty tracking */
if (old.npages)
flush_shadow = 1;
--
1.6.3.3