Vulnerability CVE-2021-47110
Published: 2024-03-15

Description:
In the Linux kernel, the following vulnerability has been resolved:

x86/kvm: Disable kvmclock on all CPUs on shutdown

Currenly, we disable kvmclock from machine_shutdown() hook and this
only happens for boot CPU. We need to disable it for all CPUs to
guard against memory corruption e.g. on restore from hibernate.

Note, writing '0' to kvmclock MSR doesn't clear memory location, it
just prevents hypervisor from updating the location so for the short
while after write and while CPU is still alive, the clock remains usable
and correct so we don't need to switch to some other clocksource.

 References:
https://git.kernel.org/stable/c/9084fe1b3572664ad276f427dce575f580c9799a
https://git.kernel.org/stable/c/3b0becf8b1ecf642a9edaf4c9628ffc641e490d6
https://git.kernel.org/stable/c/1df2dc09926f61319116c80ee85701df33577d70
https://git.kernel.org/stable/c/c02027b5742b5aa804ef08a4a9db433295533046
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