linux-stable/virt
Raghavendra Rao Ananta fb5b4d675d KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status
commit 54bbee190d upstream.

DDI0487K.a D13.3.1 describes the PMU overflow condition, which evaluates
to true if any counter's global enable (PMCR_EL0.E), overflow flag
(PMOVSSET_EL0[n]), and interrupt enable (PMINTENSET_EL1[n]) are all 1.
Of note, this does not require a counter to be enabled
(i.e. PMCNTENSET_EL0[n] = 1) to generate an overflow.

Align kvm_pmu_overflow_status() with the reality of the architecture
and stop using PMCNTENSET_EL0 as part of the overflow condition. The
bug was discovered while running an SBSA PMU test [*], which only sets
PMCR.E, PMOVSSET<0>, PMINTENSET<0>, and expects an overflow interrupt.

Cc: stable@vger.kernel.org
Fixes: 76d883c4e6 ("arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register")
Link: https://github.com/ARM-software/sbsa-acs/blob/master/test_pool/pmu/operating_system/test_pmu001.c
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
[ oliver: massaged changelog ]
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241120005230.2335682-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-19 18:05:04 +01:00
..
kvm KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
lib treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00