diff mbox

kvm: allocate correct size for dirty bitmap

Message ID 4ABA491E0200004800081D32@novprvlin0050.provo.novell.com (mailing list archive)
State New, archived
Headers show

Commit Message

Bruce Rogers Sept. 23, 2009, 10:13 p.m. UTC 
The dirty bitmap copied out to userspace is stored in a long array, and gets copied out to userspace accordingly.  This patch accounts for that correctly.  Currently I'm seeing kvm crashing due to writing beyond the end of the alloc'd dirty bitmap memory, because the buffer has the wrong size.

Signed-off-by: Bruce Rogers 
---
 qemu-kvm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)



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Comments

Marcelo Tosatti Sept. 28, 2009, 4:31 p.m. UTC | #1 
On Wed, Sep 23, 2009 at 04:13:18PM -0600, Bruce Rogers wrote:
> The dirty bitmap copied out to userspace is stored in a long array, and gets copied out to userspace accordingly.  This patch accounts for that correctly.  Currently I'm seeing kvm crashing due to writing beyond the end of the alloc'd dirty bitmap memory, because the buffer has the wrong size.
> 
> Signed-off-by: Bruce Rogers 
> ---
>  qemu-kvm.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/qemu-kvm.c b/qemu-kvm.c
> index 6511cb6..ee5db76 100644
> --- a/qemu-kvm.c
> +++ b/qemu-kvm.c
> @@ -702,7 +702,7 @@ int kvm_get_dirty_pages_range(kvm_context_t kvm, unsigned long phys_addr,
>      for (i = 0; i < KVM_MAX_NUM_MEM_REGIONS; ++i) {
>          if ((slots[i].len && (uint64_t) slots[i].phys_addr >= phys_addr)
>              && ((uint64_t) slots[i].phys_addr + slots[i].len <= end_addr)) {
> -            buf = qemu_malloc((slots[i].len / 4096 + 7) / 8 + 2);
> +            buf = qemu_malloc(BITMAP_SIZE(slots[i].len));
>              r = kvm_get_map(kvm, KVM_GET_DIRTY_LOG, i, buf);
>              if (r) {
>                  qemu_free(buf);

Applied, thanks.

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diff mbox

Patch

diff --git a/qemu-kvm.c b/qemu-kvm.c
index 6511cb6..ee5db76 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -702,7 +702,7 @@  int kvm_get_dirty_pages_range(kvm_context_t kvm, unsigned long phys_addr,
     for (i = 0; i < KVM_MAX_NUM_MEM_REGIONS; ++i) {
         if ((slots[i].len && (uint64_t) slots[i].phys_addr >= phys_addr)
             && ((uint64_t) slots[i].phys_addr + slots[i].len <= end_addr)) {
-            buf = qemu_malloc((slots[i].len / 4096 + 7) / 8 + 2);
+            buf = qemu_malloc(BITMAP_SIZE(slots[i].len));
             r = kvm_get_map(kvm, KVM_GET_DIRTY_LOG, i, buf);
             if (r) {
                 qemu_free(buf);