Hi Babis, On Wed, Aug 03, 2022 at 03:41:45PM +0200, bchal...@amazon.es wrote: > From: Babis Chalios <bchal...@amazon.es> > > VM generation ID exposes a GUID inside the VM which changes every time a > VM restore is happening. Typically, this GUID is used by the guest > kernel to re-seed its internal PRNG. As a result, this value cannot be > exposed in guest user-space as a notification mechanism for VM restore > events. > > This patch set extends vmgenid to introduce a 32 bits generation counter > whose purpose is to be used as a VM restore notification mechanism for > the guest user-space. > > It is true that such a counter could be implemented entirely by the > guest kernel, but this would rely on the vmgenid ACPI notification to > trigger the counter update, which is inherently racy. Exposing this > through the monitor allows the updated value to be in-place before > resuming the vcpus, so interested user-space code can (atomically) > observe the update without relying on the ACPI notification.
As I wrote on LKML: https://lore.kernel.org/lkml/yuve4vuanu85m...@zx2c4.com/ you seem to be rehashing something already discussed in earlier threads. I don't think we should rush to adding something like this to QEMU. Jason
