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Message-Id: <20241217212048.3709204-1-oliver.upton@linux.dev>
Date: Tue, 17 Dec 2024 13:20:30 -0800
From: Oliver Upton <oliver.upton@...ux.dev>
To: kvmarm@...ts.linux.dev
Cc: Marc Zyngier <maz@...nel.org>,
Joey Gouly <joey.gouly@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>,
Mingwei Zhang <mizhang@...gle.com>,
Colton Lewis <coltonlewis@...gle.com>,
Raghavendra Rao Ananta <rananta@...gle.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Oliver Upton <oliver.upton@...ux.dev>
Subject: [PATCH 00/18] KVM: arm64: Support FEAT_PMUv3 on Apple hardware
One of the interesting features of some Apple M* parts is an IMPDEF trap
that routes EL1/EL0 accesses of the PMUv3 registers to EL2. This allows
a hypervisor to emulate an architectural PMUv3 on top of the IMPDEF PMU
hardware present in the CPU.
And if you squint, this _might_ look like a CPU erratum :-)
This series takes advantage of these IMPDEF traps to provide PMUv3 to
KVM guests. As a starting point, only expose the fixed CPU cycle counter
and no event counters. Conveniently, this is enough to get Windows
running as a KVM guest on Apple hardware.
I've tried to keep the deviation to a minimum by refactoring some of the
flows used for PMUv3, e.g. computing PMCEID from the arm_pmu bitmap
instead of reading hardware directly.
RFC -> v1:
- Rebase to 6.13-rc3
- Add support for 1 event counter in addition to CPU cycle counter
- Don't sneak past the PMU event filter (Marc)
- Have the PMU driver provide a PMUv3 -> HW event ID mapping (Marc)
Tested on my M2 with Linux and Windows guests. If possible, I'd
appreciate someone testing on an M1 as I haven't added those MIDRs to
the erratum yet.
Oliver Upton (18):
drivers/perf: apple_m1: Refactor event select/filter configuration
drivers/perf: apple_m1: Support host/guest event filtering
drivers/perf: apple_m1: Map generic branch events
drivers/perf: apple_m1: Provide helper for mapping PMUv3 events
KVM: arm64: Compute PMCEID from arm_pmu's event bitmaps
KVM: arm64: Always support SW_INCR PMU event
KVM: arm64: Remap PMUv3 events onto hardware
KVM: arm64: Use a cpucap to determine if system supports FEAT_PMUv3
KVM: arm64: Drop kvm_arm_pmu_available static key
KVM: arm64: Use guard() to cleanup usage of arm_pmus_lock
KVM: arm64: Move PMUVer filtering into KVM code
KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps
KVM: arm64: Advertise PMUv3 if IMPDEF traps are present
KVM: arm64: Advertise 0 event counters for IMPDEF PMU
arm64: Enable IMP DEF PMUv3 traps on Apple M2
drivers/perf: apple_m1: Map a few more PMUv3 events
KVM: arm64: Provide 1 event counter on IMPDEF hardware
KVM: arm64: selftests: Add test for probing PMUv3 sysregs
arch/arm64/include/asm/apple_m1_pmu.h | 1 +
arch/arm64/include/asm/cpufeature.h | 28 +---
arch/arm64/kernel/cpu_errata.c | 38 +++++
arch/arm64/kernel/cpufeature.c | 19 +++
arch/arm64/kernel/image-vars.h | 5 -
arch/arm64/kvm/arm.c | 4 +-
arch/arm64/kvm/hyp/include/hyp/switch.h | 4 +-
arch/arm64/kvm/hyp/vhe/switch.c | 22 +++
arch/arm64/kvm/pmu-emul.c | 127 +++++++++++-----
arch/arm64/kvm/pmu.c | 10 +-
arch/arm64/tools/cpucaps | 2 +
drivers/perf/apple_m1_cpu_pmu.c | 103 ++++++++++---
include/kvm/arm_pmu.h | 15 +-
include/linux/perf/arm_pmu.h | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/aarch64/pmuv3_register_probe.c | 135 ++++++++++++++++++
16 files changed, 407 insertions(+), 108 deletions(-)
create mode 100644 tools/testing/selftests/kvm/aarch64/pmuv3_register_probe.c
base-commit: 78d4f34e2115b517bcbfe7ec0d018bbbb6f9b0b8
--
2.39.5
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