Support ROM blobs not mapped into guest memory:
same as ROM files really but use caller's buffer.
Support invoking callback on access and
return memory pointer making it easier
for caller to update memory if necessary.
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
ROM files that are put in FW CFG are copied to guest ram, by BIOS, but
they are not backed by RAM so they don't get migrated.
Each time we change two bytes in such a ROM this breaks cross-version
migration: since we can migrate after BIOS has read the first byte but
before it has read the second one, getting an inconsistent state.
Future-proof this by creating, for each such ROM,
an MR serving as the backing store.
This MR is never mapped into guest memory, but it's registered
as RAM so it's migrated with the guest.
Naturally, this only helps for -M 1.7 and up, older machine types
will still have the cross-version migration bug.
Luckily the race window for the problem to trigger is very small,
which is also likely why we didn't notice the cross-version
migration bug in testing yet.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Add ref/unref calls at the following places:
- places where memory regions are stashed by a listener and
used outside the BQL (including in Xen or KVM).
- memory_region_find callsites
- creation of aliases and containers (only the aliased/contained
region gets a reference to avoid loops)
- around calls to del_subregion/add_subregion, where the region
could disappear after the first call
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
So far, the size of all regions passed to listeners could fit in 64 bits,
because artificial regions (containers and aliases) are eliminated by
the memory core, leaving only device regions which have reasonable sizes
An IOMMU however cannot be eliminated by the memory core, and may have
an artificial size, hence we may need 65 bits to represent its size.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently some places use pointer-to-void even though they mean
pointer-to-FWCfgState. Clean them up.
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
