CVE-2021-46977 Information

Description

In the Linux kernel the following vulnerability has been resolved:

KVM: VMX: Disable preemption when probing user return MSRs

Disable preemption when probing a user return MSR via RDSMR/WRMSR. If the MSR holds a different value per logical CPU the WRMSR could corrupt the host’s value if KVM is preempted between the RDMSR and WRMSR and then rescheduled on a different CPU.

Opportunistically land the helper in common x86 SVM will use the helper in a future commit.

Reference

https://git.kernel.org/stable/c/31f29749ee970c251b3a7e5b914108425940d089 https://git.kernel.org/stable/c/5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 https://git.kernel.org/stable/c/e3ea1895df719c4ef87862501bb10d95f4177bed https://git.kernel.org/stable/c/5104d7ffcf24749939bea7fdb5378d186473f890