[PATCH v2 46/54] perf/x86/amd/core: Set passthrough capability for host

Mingwei Zhang
2024-05-06T05:31:54Z

From: Sandipan Das <sandipan.das@amd.com>

Apply the PERF_PMU_CAP_PASSTHROUGH_VPMU flag for version 2 and later
implementations of the core PMU. Aside from having Global Control and
Status registers, virtualizing the PMU using the passthrough model
requires an interface to set or clear the overflow bits in the Global
Status MSRs while restoring or saving the PMU context of a vCPU.

PerfMonV2-capable hardware has additional MSRs for this purpose namely,
PerfCntrGlobalStatusSet and PerfCntrGlobalStatusClr, thereby making it
suitable for use with passthrough PMU.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
arch/x86/events/amd/core.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 985ef3b47919..7a91c991779c 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1395,6 +1395,9 @@ static int __init amd_core_pmu_init(void)

amd_pmu_global_cntr_mask = (1ULL << x86_pmu.num_counters) - 1;

+ x86_pmu.flags |= PMU_FL_PASSTHROUGH;
+ x86_get_pmu(smp_processor_id())->capabilities |= PERF_PMU_CAP_PASSTHROUGH_VPMU;
+
/* Update PMC handling functions */
x86_pmu.enable_all = amd_pmu_v2_enable_all;
x86_pmu.disable_all = amd_pmu_v2_disable_all;
--
2.45.0.rc1.225.g2a3ae87e7f-goog