hostmem: detect host backend memory is being used properly

Currently, we use memory_region_is_mapped() to detect if the host
backend memory is being used. This works if the memory is directly
mapped into guest's address space, however, it is not true for
nvdimm as it uses aliased memory region to map the memory. This is
why this bug can happen:
   https://bugzilla.redhat.com/show_bug.cgi?id=1352769

Fix it by introduce a new filed, is_mapped, to HostMemoryBackend,
we set/clear this filed accordingly when the device link/unlink to
host backend memory

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiao Guangrong 2016-07-13 12:18:06 +08:00 committed by Paolo Bonzini
parent 1454d33f05
commit 2aece63c8a
4 changed files with 35 additions and 16 deletions

View file

@ -264,6 +264,16 @@ host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
return memory_region_size(&backend->mr) ? &backend->mr : NULL;
}
void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
{
backend->is_mapped = mapped;
}
bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
{
return backend->is_mapped;
}
static void
host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
{
@ -341,10 +351,7 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
static bool
host_memory_backend_can_be_deleted(UserCreatable *uc, Error **errp)
{
MemoryRegion *mr;
mr = host_memory_backend_get_memory(MEMORY_BACKEND(uc), errp);
if (memory_region_is_mapped(mr)) {
if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
return false;
} else {
return true;