Re: [PATCH 6/6] KVM: arm64: Upgrade PMU support to ARMv8.4
From: Auger Eric <eric.auger@redhat.com>
Date: 2021-01-15 14:03:08
Also in:
kvmarm, linux-arm-kernel
Hi Marc, On 1/14/21 11:56 AM, Marc Zyngier wrote:
quoted hunk ↗ jump to hunk
Upgrading the PMU code from ARMv8.1 to ARMv8.4 turns out to be pretty easy. All that is required is support for PMMIR_EL1, which is read-only, and for which returning 0 is a valid option. Let's just do that and adjust what we return to the guest. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/sys_regs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 8f79ec1fffa7..2f4ecbd2abfb 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c@@ -1051,10 +1051,10 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, /* Limit debug to ARMv8.0 */ val &= ~FEATURE(ID_AA64DFR0_DEBUGVER); val |= FIELD_PREP(FEATURE(ID_AA64DFR0_DEBUGVER), 6); - /* Limit guests to PMUv3 for ARMv8.1 */ + /* Limit guests to PMUv3 for ARMv8.4 */ val = cpuid_feature_cap_perfmon_field(val, ID_AA64DFR0_PMUVER_SHIFT, - kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_1 : 0); + kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_4 : 0); break; case SYS_ID_DFR0_EL1: /* Limit guests to PMUv3 for ARMv8.1 */
what about the debug version in aarch32 state. Is it on purpose that you leave it as 8_1? Thanks Eric
quoted hunk ↗ jump to hunk
@@ -1496,6 +1496,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_PMINTENSET_EL1), access_pminten, reset_unknown, PMINTENSET_EL1 }, { SYS_DESC(SYS_PMINTENCLR_EL1), access_pminten, reset_unknown, PMINTENSET_EL1 }, + { SYS_DESC(SYS_PMMIR_EL1), trap_raz_wi }, { SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 }, { SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 },