This kernel-linus update is based on upstream 5.10.60 and fixes at least the following security issues:
A missing validation of the "int_ctl" VMCB field allows a malicious L1 guest to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. The L2 guest is able to write to a limited but still relatively large subset of the host physical memory, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape (CVE-2021-3653).
A missing validation of the the "virt_ext" VMCB field and allows a malicious L1 guest to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. Under these circumstances, the L2 guest is able to run VMLOAD/VMSAVE unintercepted, and thus read/write portions of the host physical memory, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape (CVE-2021-3656).
In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket (CVE-2021-38166).
drivers/net/ethernet/xilinx/xilinx_emaclite.c in the Linux kernel before 5.13.3 makes it easier for attackers to defeat an ASLR protection mechanism because it prints a kernel pointer (CVE-2021-38205).
For other upstream fixes, see the referenced changelogs.