CVE-2021-47389

In the Linux kernel, the following vulnerability has been resolved: KVM:
SVM: fix missing sev_decommission in sev_receive_start DECOMMISSION the
current SEV context if binding an ASID fails after RECEIVE_START. Per AMD’s
SEV API, RECEIVE_START generates a new guest context and thus needs to be
paired with DECOMMISSION: The RECEIVE_START command is the only command
other than the LAUNCH_START command that generates a new guest context and
guest handle. The missing DECOMMISSION can result in subsequent SEV launch
failures, as the firmware leaks memory and might not able to allocate more
SEV guest contexts in the future. Note, LAUNCH_START suffered the same bug,
but was previously fixed by commit 934002cd660b (“KVM: SVM: Call SEV Guest
Decommission if ASID binding fails”).