[PATCH v2 3/4] KVM: cleanup: remove kvm_get_dirty_log()

Takuya Yoshikawa
2010-06-23T06:01:34Z

kvm_get_dirty_log() is a helper function for kvm_vm_ioctl_get_dirty_log() which
is currently used by ia64 and ppc and the following is what it is doing:

- sanity checks
- bitmap scan to check if the slot is dirty
- copy_to_user()

Considering the fact that x86 is not using this anymore and sanity checks must
be done before kvm_ia64_sync_dirty_log(), we can say that this is not working
for code sharing effectively. So we just remove this.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya-gVGce1chcLdL9jVzuh4AOg@public.gmane.org>
---
arch/ia64/kvm/kvm-ia64.c | 20 ++++++++++++++------
arch/powerpc/kvm/book3s.c | 29 ++++++++++++++++++++++-------
include/linux/kvm_host.h | 2 --
virt/kvm/kvm_main.c | 34 ----------------------------------
4 files changed, 36 insertions(+), 49 deletions(-)

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 5cb5865..da0c133 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1818,10 +1818,10 @@ static void kvm_ia64_sync_dirty_log(struct kvm *kvm,
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
- int r;
+ int r, i;
unsigned long n;
struct kvm_memory_slot *memslot;
- int is_dirty = 0;
+ unsigned long is_dirty = 0;

mutex_lock(&kvm->slots_lock);

@@ -1835,15 +1835,23 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
goto out;

kvm_ia64_sync_dirty_log(kvm, memslot);
- r = kvm_get_dirty_log(kvm, log, &is_dirty);
- if (r)
- goto out;
+
+ n = kvm_dirty_bitmap_bytes(memslot);
+
+ for (i = 0; !is_dirty && i < n/sizeof(long); ++i)
+ is_dirty = memslot->dirty_bitmap[i];

/* If nothing is dirty, don't bother messing with page tables. */
if (is_dirty) {
kvm_flush_remote_tlbs(kvm);
- n = kvm_dirty_bitmap_bytes(memslot);
+ r = -EFAULT;
+ if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
+ goto out;
memset(memslot->dirty_bitmap, 0, n);
+ } else {
+ r = -EFAULT;
+ if (clear_user(log->dirty_bitmap, n))
+ goto out;
}
r = 0;
out:
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 801d9f3..bea6f7c 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -1185,28 +1185,43 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_memory_slot *memslot;
struct kvm_vcpu *vcpu;
ulong ga, ga_end;
- int is_dirty = 0;
- int r;
+ unsigned long is_dirty = 0;
+ int r, i;
unsigned long n;

mutex_lock(&kvm->slots_lock);

- r = kvm_get_dirty_log(kvm, log, &is_dirty);
- if (r)
+ r = -EINVAL;
+ if (log->slot >= KVM_MEMORY_SLOTS)
+ goto out;
+
+ memslot = &kvm->memslots->memslots[log->slot];
+ r = -ENOENT;
+ if (!memslot->dirty_bitmap)
goto out;

+ n = kvm_dirty_bitmap_bytes(memslot);
+
+ for (i = 0; !is_dirty && i < n/sizeof(long); ++i)
+ is_dirty = memslot->dirty_bitmap[i];
+
/* If nothing is dirty, don't bother messing with page tables. */
if (is_dirty) {
- memslot = &kvm->memslots->memslots[log->slot];
-
ga = memslot->base_gfn << PAGE_SHIFT;
ga_end = ga + (memslot->npages << PAGE_SHIFT);

kvm_for_each_vcpu(n, vcpu, kvm)
kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);

- n = kvm_dirty_bitmap_bytes(memslot);
+ r = -EFAULT;
+ if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
+ goto out;
+
memset(memslot->dirty_bitmap, 0, n);
+ } else {
+ r = -EFAULT;
+ if (clear_user(log->dirty_bitmap, n))
+ goto out;
}

r = 0;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e796326..b51e6b2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -336,8 +336,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,

int kvm_dev_ioctl_check_extension(long ext);

-int kvm_get_dirty_log(struct kvm *kvm,
- struct kvm_dirty_log *log, int *is_dirty);
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log);

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 74f7319..8859049 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -773,40 +773,6 @@ int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
return kvm_set_memory_region(kvm, mem, user_alloc);
}

-int kvm_get_dirty_log(struct kvm *kvm,
- struct kvm_dirty_log *log, int *is_dirty)
-{
- struct kvm_memory_slot *memslot;
- int r, i;
- unsigned long n;
- unsigned long any = 0;
-
- r = -EINVAL;
- if (log->slot >= KVM_MEMORY_SLOTS)
- goto out;
-
- memslot = &kvm->memslots->memslots[log->slot];
- r = -ENOENT;
- if (!memslot->dirty_bitmap)
- goto out;
-
- n = kvm_dirty_bitmap_bytes(memslot);
-
- for (i = 0; !any && i < n/sizeof(long); ++i)
- any = memslot->dirty_bitmap[i];
-
- r = -EFAULT;
- if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
- goto out;
-
- if (any)
- *is_dirty = 1;
-
- r = 0;
-out:
- return r;
-}
-
void kvm_disable_largepages(void)
{
largepages_enabled = false;
--
1.7.0.4