This is a note to let you know that I've just added the patch titled
arm64: perf: Ignore exclude_hv when kernel is running in HYP
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: arm64-perf-ignore-exclude_hv-when-kernel-is-running-in-hyp.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Apr 9 17:09:24 CEST 2018
From: Ganapatrao Kulkarni ganapatrao.kulkarni@cavium.com Date: Tue, 2 May 2017 21:59:34 +0530 Subject: arm64: perf: Ignore exclude_hv when kernel is running in HYP
From: Ganapatrao Kulkarni ganapatrao.kulkarni@cavium.com
[ Upstream commit 78a19cfdf37d19002c83c8790853c1cc10feccdc ]
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 [will: added comment to justify the behaviour of exclude_hv] Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/perf_event.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-)
--- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -871,15 +871,24 @@ static int armv8pmu_set_event_filter(str
if (attr->exclude_idle) return -EPERM; - if (is_kernel_in_hyp_mode() && - attr->exclude_kernel != attr->exclude_hv) - return -EINVAL; + + /* + * If we're running in hyp mode, then we *are* the hypervisor. + * Therefore we ignore exclude_hv in this configuration, since + * there's no hypervisor to sample anyway. This is consistent + * with other architectures (x86 and Power). + */ + 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
Patches currently in stable-queue which might be from ganapatrao.kulkarni@cavium.com are
queue-4.9/arm64-perf-ignore-exclude_hv-when-kernel-is-running-in-hyp.patch