| 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 |