diff options
| author | Andrew Murray <andrew.murray@arm.com> | 2019-04-09 21:22:15 +0200 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-04-24 16:46:26 +0200 |
| commit | 435e53fb5e21ad1820c5c69f208304c0e5623d01 (patch) | |
| tree | b3ad2d97114ca99f78c6edcc76c7b0e1446df91b /arch/arm64/kernel | |
| parent | arm64: KVM: Enable !VHE support for :G/:H perf event modifiers (diff) | |
| download | linux-435e53fb5e21ad1820c5c69f208304c0e5623d01.tar.xz linux-435e53fb5e21ad1820c5c69f208304c0e5623d01.zip | |
arm64: KVM: Enable VHE support for :G/:H perf event modifiers
With VHE different exception levels are used between the host (EL2) and
guest (EL1) with a shared exception level for userpace (EL0). We can take
advantage of this and use the PMU's exception level filtering to avoid
enabling/disabling counters in the world-switch code. Instead we just
modify the counter type to include or exclude EL0 at vcpu_{load,put} time.
We also ensure that trapped PMU system register writes do not re-enable
EL0 when reconfiguring the backing perf events.
This approach completely avoids blackout windows seen with !VHE.
Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/perf_event.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 6bb28aaf5aea..314b1adedf06 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -847,8 +847,12 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, * with other architectures (x86 and Power). */ if (is_kernel_in_hyp_mode()) { - if (!attr->exclude_kernel) + if (!attr->exclude_kernel && !attr->exclude_host) config_base |= ARMV8_PMU_INCLUDE_EL2; + if (attr->exclude_guest) + config_base |= ARMV8_PMU_EXCLUDE_EL1; + if (attr->exclude_host) + config_base |= ARMV8_PMU_EXCLUDE_EL0; } else { if (!attr->exclude_hv && !attr->exclude_host) config_base |= ARMV8_PMU_INCLUDE_EL2; |