Merge tag 'x86-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Thomas Gleixner:
"A single fix for x86 which removes the RDPID usage from the paranoid
entry path and unconditionally uses LSL to retrieve the CPU number.
RDPID depends on MSR_TSX_AUX. KVM has an optmization to avoid
expensive MRS read/writes on VMENTER/EXIT. It caches the MSR values
and restores them either when leaving the run loop, on preemption or
when going out to user space. MSR_TSX_AUX is part of that lazy MSR
set, so after writing the guest value and before the lazy restore any
exception using the paranoid entry will read the guest value and use
it as CPU number to retrieve the GSBASE value for the current CPU when
FSGSBASE is enabled. As RDPID is only used in that particular entry
path, there is no reason to burden VMENTER/EXIT with two extra MSR
writes. Remove the RDPID optimization, which is not even backed by
numbers from the paranoid entry path instead"
* tag 'x86-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM
