[Qemu-devel] [PATCH] kvm: Fix dirty tracking with large kernel page size

[David Gibson <david@gibson.dropbear.id.au>]

If the kernel page size is larger than TARGET_PAGE_SIZE, which
happens for example on ppc64 with kernels compiled for 64K pages,
the dirty tracking doesn't work.

Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tossatti <mtosatti@redhat.com>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 kvm-all.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index ba2cee1..47adc97 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -350,10 +350,11 @@ static int kvm_set_migration_log(int enable)
 static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section,
                                          unsigned long *bitmap)
 {
-    unsigned int i, j;
+  unsigned int i, j;
     unsigned long page_number, c;
     target_phys_addr_t addr, addr1;
     unsigned int len = ((section->size / TARGET_PAGE_SIZE) + HOST_LONG_BITS - 1) / HOST_LONG_BITS;
+    unsigned long hpratio = getpagesize() / TARGET_PAGE_SIZE;
 
     /*
      * bitmap-traveling is faster than memory-traveling (for addr...)
@@ -365,10 +366,11 @@ static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section,
             do {
                 j = ffsl(c) - 1;
                 c &= ~(1ul << j);
-                page_number = i * HOST_LONG_BITS + j;
+                page_number = (i * HOST_LONG_BITS + j) * hpratio;
                 addr1 = page_number * TARGET_PAGE_SIZE;
                 addr = section->offset_within_region + addr1;
-                memory_region_set_dirty(section->mr, addr, TARGET_PAGE_SIZE);
+                memory_region_set_dirty(section->mr, addr,
+                                        TARGET_PAGE_SIZE * hpratio);
             } while (c != 0);
         }
     }
-- 
1.7.9.1