On a Linux 3.8.0 based kernel, I occasionally saw a situation
where the memory region would continue to trap on memory
read even though KVM_MEM_READONLY was set.
I found that if I set the slot to a size of 0, and before
setting the slot, it would then behave as expected.
Signed-off-by: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Xiao Guangrong <xiaoguangr...@linux.vnet.ibm.com>
---
kvm-all.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kvm-all.c b/kvm-all.c
index 95e6bf2..e2ddbcb 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -205,6 +205,13 @@ static int kvm_set_user_memory_region(KVMState *s, KVMSlot
*slot)
if (s->migration_log) {
mem.flags |= KVM_MEM_LOG_DIRTY_PAGES;
}
+ if (mem.flags & KVM_MEM_READONLY && mem.memory_size != 0) {
+ /* Workaround an issue with setting a READONLY slot. Set the
+ * slot size to 0 before setting the slot to the desired value. */
+ mem.memory_size = 0;
+ kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+ mem.memory_size = slot->memory_size;
+ }
return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
}
--
1.7.10.4
