accel: kvm: Add aligment assert for kvm_log_clear_one_slot
The parameters start and size are transfered from QEMU memory
emulation layer. It can promise that they are TARGET_PAGE_SIZE
aligned. However, KVM needs they are qemu_real_page_size aligned.
Though no caller breaks this aligned requirement currently, we'd
better add an explicit assert to avoid future breaking.
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20201217014941.22872-3-zhukeqian1@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index ffce83f..f88a523 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -673,6 +673,10 @@
#define KVM_CLEAR_LOG_ALIGN (qemu_real_host_page_size << KVM_CLEAR_LOG_SHIFT)
#define KVM_CLEAR_LOG_MASK (-KVM_CLEAR_LOG_ALIGN)
+/*
+ * As the granule of kvm dirty log is qemu_real_host_page_size,
+ * @start and @size are expected and restricted to align to it.
+ */
static int kvm_log_clear_one_slot(KVMSlot *mem, int as_id, uint64_t start,
uint64_t size)
{
@@ -682,6 +686,9 @@
unsigned long *bmap_clear = NULL, psize = qemu_real_host_page_size;
int ret;
+ /* Make sure start and size are qemu_real_host_page_size aligned */
+ assert(QEMU_IS_ALIGNED(start | size, psize));
+
/*
* We need to extend either the start or the size or both to
* satisfy the KVM interface requirement. Firstly, do the start
