diff options
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/hyp/pgtable.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 8f37e65c23ee..ae5f6b5ac80f 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -598,10 +598,18 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift) #ifdef CONFIG_ARM64_HW_AFDBM /* * Enable the Hardware Access Flag management, unconditionally - * on all CPUs. The features is RES0 on CPUs without the support - * and must be ignored by the CPUs. + * on all CPUs. In systems that have asymmetric support for the feature + * this allows KVM to leverage hardware support on the subset of cores + * that implement the feature. + * + * The architecture requires VTCR_EL2.HA to be RES0 (thus ignored by + * hardware) on implementations that do not advertise support for the + * feature. As such, setting HA unconditionally is safe, unless you + * happen to be running on a design that has unadvertised support for + * HAFDBS. Here be dragons. */ - vtcr |= VTCR_EL2_HA; + if (!cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38)) + vtcr |= VTCR_EL2_HA; #endif /* CONFIG_ARM64_HW_AFDBM */ /* Set the vmid bits */ |