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| author | Nicholas Piggin <npiggin@gmail.com> | 2017-08-25 14:30:33 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-29 14:48:59 +1000 |
| commit | 94a04bc25a2c6296bd0c5e82c10e8231c2b11f77 (patch) | |
| tree | e299908064b8b13718b6f5915d9469d103125b0d /arch/powerpc/include/asm/kvm_book3s_asm.h | |
| parent | 94171b19c3f1f4d9d4c0e3aaa1aa161def1ec7ea (diff) | |
| download | linux-rt-94a04bc25a2c6296bd0c5e82c10e8231c2b11f77.tar.gz | |
KVM: PPC: Book3S HV: POWER9 does not require secondary thread management
POWER9 CPUs have independent MMU contexts per thread, so KVM does not
need to quiesce secondary threads, so the hwthread_req/hwthread_state
protocol does not have to be used. So patch it away on POWER9, and patch
away the branch from the Linux idle wakeup to kvm_start_guest that is
never used.
Add a warning and error out of kvmppc_grab_hwthread in case it is ever
called on POWER9.
This avoids a hwsync in the idle wakeup path on POWER9.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Use WARN(...) instead of WARN_ON()/pr_err(...)]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/kvm_book3s_asm.h')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_book3s_asm.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h index 7cea76f11c26..83596f32f50b 100644 --- a/arch/powerpc/include/asm/kvm_book3s_asm.h +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h @@ -104,6 +104,10 @@ struct kvmppc_host_state { u8 napping; #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE + /* + * hwthread_req/hwthread_state pair is used to pull sibling threads + * out of guest on pre-ISAv3.0B CPUs where threads share MMU. + */ u8 hwthread_req; u8 hwthread_state; u8 host_ipi; |