[PATCH 3/4] arm64: arm_pmu: Exclude EL1,2 with :G :H perf attributes

From: Andrew Murray <andrew.murray@arm.com>
To: Christoffer Dall <christoffer.dall@arm.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Mark Rutland <mark.rutland@arm.com>
Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/4] arm64: arm_pmu: Exclude EL1,2 with :G :H perf attributes
Date: Thu, 15 Nov 2018 12:55:48 +0000	[thread overview]
Message-ID: <1542286549-4501-4-git-send-email-andrew.murray@arm.com> (raw)
In-Reply-To: <1542286549-4501-1-git-send-email-andrew.murray@arm.com>

When using VHE, EL1 is unused by the host and EL2 is unused by the
guest - therefore we can filter out these events with the PMU as per
the 'exclude_host' and 'exclude_guest' attributes.

With both VHE and non-VHE we switch the counters between host/guest
at EL2. With non-VHE when using 'exclude_host' we filter out EL2.

These changes eliminate counters counting host events on the
boundaries of guest entry/exit when using :G. However when using :H
unless exclude_hv is set on non-VHE then there is a small blackout
window at the guest entry/exit where host events are not captured.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
---
 arch/arm64/kernel/perf_event.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 89d444f..c079c1f 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -971,12 +971,14 @@ 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;
 	} else {
 		if (attr->exclude_kernel)
 			config_base |= ARMV8_PMU_EXCLUDE_EL1;
-		if (!attr->exclude_hv)
+		if (!attr->exclude_hv && !attr->exclude_host)
 			config_base |= ARMV8_PMU_INCLUDE_EL2;
 	}
 	if (attr->exclude_user)
-- 
2.7.4
