From: Andrew Murray <andrew.murray@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Murray <andrew.murray@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 0/3] arm64: perf: Add support for ARMv8.5-PMU 64-bit counters
Date: Mon, 27 Jan 2020 11:44:26 +0000 [thread overview]
Message-ID: <1580125469-23887-1-git-send-email-andrew.murray@arm.com> (raw)
At present ARMv8 event counters are limited to 32-bits, though by
using the CHAIN event it's possible to combine adjacent counters to
achieve 64-bits. The perf config1:0 bit can be set to use such a
configuration.
With the introduction of ARMv8.5-PMU support, all event counters can
now be used as 64-bit counters. Let's add support for 64-bit event
counters.
As KVM doesn't yet support 64-bit event counters (or other features
after PMUv3 for ARMv8.1), we also trap and emulate the Debug Feature
Registers to limit the PMU version a guest sees to PMUv3 for ARMv8.1.
Tested by running the following perf command on both guest and host
and ensuring that the figures are very similar:
perf stat -e armv8_pmuv3/inst_retired,long=1/ \
-e armv8_pmuv3/inst_retired,long=0/ -e cycles
Changes since v4:
- Limit KVM to PMUv3 for ARMv8.1 instead of 8.4
- Reword second commit
Changes since v3:
- Rebased onto v5.5-rc7
- Instead of overriding trap access handler, update read_id_reg
Changes since v2:
- Rebased onto v5.5-rc4
- Mask 'cap' value to 'width' in cpuid_feature_cap_signed_field_width
Changes since v1:
- Rebased onto v5.5-rc1
Andrew Murray (3):
arm64: cpufeature: Extract capped fields
KVM: arm64: limit PMU version to PMUv3 for ARMv8.1
arm64: perf: Add support for ARMv8.5-PMU 64-bit counters
arch/arm64/include/asm/cpufeature.h | 16 +++++++
arch/arm64/include/asm/perf_event.h | 3 +-
arch/arm64/include/asm/sysreg.h | 6 +++
arch/arm64/kernel/perf_event.c | 86 +++++++++++++++++++++++++++++--------
arch/arm64/kvm/sys_regs.c | 11 +++++
include/linux/perf/arm_pmu.h | 1 +
6 files changed, 105 insertions(+), 18 deletions(-)
--
2.7.4
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next reply other threads:[~2020-01-27 11:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 11:44 Andrew Murray [this message]
2020-01-27 11:44 ` [PATCH v5 1/3] arm64: cpufeature: Extract capped fields Andrew Murray
2020-02-11 16:59 ` Suzuki Kuruppassery Poulose
2020-01-27 11:44 ` [PATCH v5 2/3] KVM: arm64: limit PMU version to PMUv3 for ARMv8.1 Andrew Murray
2020-02-11 17:55 ` Suzuki Kuruppassery Poulose
2020-02-28 16:51 ` Mark Rutland
2020-02-28 18:22 ` Mark Rutland
2020-01-27 11:44 ` [PATCH v5 3/3] arm64: perf: Add support for ARMv8.5-PMU 64-bit counters Andrew Murray
2020-01-27 12:32 ` Marc Zyngier
2020-01-28 8:53 ` Andrew Murray
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