From: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Will.Deacon@arm.com, catalin.marinas@arm.com,
mark.rutland@arm.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, peterz@infradead.org,
mingo@redhat.com, jnair@caviumnetworks.com, gpkulkarni@gmail.com
Subject: [PATCH v3] arm64: perf: Ignore exclude_hv when kernel is running in HYP
Date: Tue, 2 May 2017 21:59:34 +0530 [thread overview]
Message-ID: <1493742574-25955-1-git-send-email-ganapatrao.kulkarni@cavium.com> (raw)
commit d98ecdaca296 ("arm64: perf: Count EL2 events if the kernel is
running in HYP") returns -EINVAL when perf system call perf_event_open is
called with exclude_hv != exclude_kernel. This change breaks applications
on VHE enabled ARMv8.1 platforms. The issue was observed with HHVM
application, which calls perf_event_open with exclude_hv = 1 and
exclude_kernel = 0.
There is no separate hypervisor privilege level when VHE is enabled, the
host kernel runs at EL2. So when VHE is enabled, we should ignore
exclude_hv from the application. This behaviour is consistent with PowerPC
where the exclude_hv is ignored when the hypervisor is not present and with
x86 where this flag is ignored.
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
---
Changelog:
V2/V3:
- Changes as per Will Deacon's suggestions.
V1: Initial patch
arch/arm64/kernel/perf_event.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 57ae9d9..f6748c0 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -871,15 +871,17 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
if (attr->exclude_idle)
return -EPERM;
- if (is_kernel_in_hyp_mode() &&
- attr->exclude_kernel != attr->exclude_hv)
- return -EINVAL;
+ if (is_kernel_in_hyp_mode()) {
+ if (!attr->exclude_kernel)
+ config_base |= ARMV8_PMU_INCLUDE_EL2;
+ } else {
+ if (attr->exclude_kernel)
+ config_base |= ARMV8_PMU_EXCLUDE_EL1;
+ if (!attr->exclude_hv)
+ config_base |= ARMV8_PMU_INCLUDE_EL2;
+ }
if (attr->exclude_user)
config_base |= ARMV8_PMU_EXCLUDE_EL0;
- if (!is_kernel_in_hyp_mode() && attr->exclude_kernel)
- config_base |= ARMV8_PMU_EXCLUDE_EL1;
- if (!attr->exclude_hv)
- config_base |= ARMV8_PMU_INCLUDE_EL2;
/*
* Install the filter into config_base as this is used to
--
1.8.1.4
next reply other threads:[~2017-05-02 16:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-02 16:29 Ganapatrao Kulkarni [this message]
2017-05-15 9:01 ` [PATCH v3] arm64: perf: Ignore exclude_hv when kernel is running in HYP Ganapatrao Kulkarni
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