KVM: PPC: Book3S HV Nested: Avoid extra mftb() in nested entry

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mftb() is expensive and one can be avoided on nested guest dispatch.

If the time checking code distinguishes between the L0 timer and the
nested HV timer, then both can be tested in the same place with the
same mftb() value.

This also nicely illustrates the relationship between the L0 and nested
HV timers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-45-npiggin@gmail.com

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Nicholas Piggin 2021-11-23 19:52:22 +10:00 • committed by Michael Ellerman

parent d5c0e8332d

commit 46dea77f79

3 changed files with 13 additions and 5 deletions

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1

arch/powerpc/include/asm/kvm_asm.h

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12

arch/powerpc/kvm/book3s_hv.c

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5

arch/powerpc/kvm/book3s_hv_nested.c

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