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powerpc/64s: Always set PMU control registers to frozen/disabled when not in use

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KVM PMU management code looks for particular frozen/disabled bits in
the PMU registers so it knows whether it must clear them when coming
out of a guest or not. Setting this up helps KVM make these optimisations
without getting confused. Longer term the better approach might be to
move guest/host PMU switching to the perf subsystem.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-12-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-11-23 19:51:49 +10:00 committed by Michael Ellerman
parent d3c8a2d374
commit 245ebf8e73
3 changed files with 10 additions and 5 deletions
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4
arch/powerpc/kernel/cpu_setup_power.c
View file

@ -109,7 +109,7 @@ static void init_PMU_HV_ISA207(void)
static void init_PMU(void)
{
mtspr(SPRN_MMCRA, 0);
mtspr(SPRN_MMCR0, 0);
mtspr(SPRN_MMCR0, MMCR0_FC);
mtspr(SPRN_MMCR1, 0);
mtspr(SPRN_MMCR2, 0);
}
@ -123,7 +123,7 @@ static void init_PMU_ISA31(void)
{
mtspr(SPRN_MMCR3, 0);
mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMCCEXT);
}
/*

6
arch/powerpc/kernel/dt_cpu_ftrs.c
View file

@ -353,7 +353,7 @@ static void init_pmu_power8(void)
}
mtspr(SPRN_MMCRA, 0);
mtspr(SPRN_MMCR0, 0);
mtspr(SPRN_MMCR0, MMCR0_FC);
mtspr(SPRN_MMCR1, 0);
mtspr(SPRN_MMCR2, 0);
mtspr(SPRN_MMCRS, 0);
@ -392,7 +392,7 @@ static void init_pmu_power9(void)
mtspr(SPRN_MMCRC, 0);
mtspr(SPRN_MMCRA, 0);
mtspr(SPRN_MMCR0, 0);
mtspr(SPRN_MMCR0, MMCR0_FC);
mtspr(SPRN_MMCR1, 0);
mtspr(SPRN_MMCR2, 0);
}
@ -428,7 +428,7 @@ static void init_pmu_power10(void)
mtspr(SPRN_MMCR3, 0);
mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMCCEXT);
}
static int __init feat_enable_pmu_power10(struct dt_cpu_feature *f)

5
arch/powerpc/kvm/book3s_hv.c
View file

@ -2715,6 +2715,11 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu)
#endif
#endif
vcpu->arch.mmcr[0] = MMCR0_FC;
if (cpu_has_feature(CPU_FTR_ARCH_31)) {
vcpu->arch.mmcr[0] |= MMCR0_PMCCEXT;
vcpu->arch.mmcra = MMCRA_BHRB_DISABLE;
}
vcpu->arch.ctrl = CTRL_RUNLATCH;
/* default to host PVR, since we can't spoof it */
kvmppc_set_pvr_hv(vcpu, mfspr(SPRN_PVR));