On 8/24/2021 11:55 AM, Bjorn Helgaas wrote:
[+cc Rajat; I still don't know what "shared memory with a hypervisor in a confidential guest" means,
A confidential guest is a guest which uses memory encryption to isolate itself from the host. It doesn't trust the host. But it still needs to communicate with the host for IO, so it has some special memory areas that are explicitly marked shared. These are used to do IO with the host. All their usage needs to be carefully hardened to avoid any security attacks on the guest, that's why we want to limit this interaction only to a small set of hardened drivers. For MMIO, the set is currently only virtio and MSI-X.
-Andi
