KVM: PPC: Book3S HV P9: Avoid cpu_in_guest atomics on entry and exit

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cpu_in_guest is set to determine if a CPU needs to be IPI'ed to exit
the guest and notice the need_tlb_flush bit.

This can be implemented as a global per-CPU pointer to the currently
running guest instead of per-guest cpumasks, saving 2 atomics per
entry/exit. P7/8 doesn't require cpu_in_guest, nor does a nested HV
(only the L0 does), so move it to the P9 HV path.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-50-npiggin@gmail.com

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Nicholas Piggin 2021-11-23 19:52:27 +10:00 • committed by Michael Ellerman

parent 4c9a68914e

commit 434398ab5e

3 changed files with 22 additions and 19 deletions

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arch/powerpc/include/asm/kvm_book3s_64.h

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arch/powerpc/include/asm/kvm_host.h

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39

arch/powerpc/kvm/book3s_hv.c

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