diff mbox series

[RFC,v3,45/58] KVM: x86/pmu: Update pmc_{read,write}_counter() to disconnect perf API

Message ID 20240801045907.4010984-46-mizhang@google.com (mailing list archive)
State New, archived
Headers show
Series Mediated Passthrough vPMU 3.0 for x86 | expand

Commit Message

Mingwei Zhang Aug. 1, 2024, 4:58 a.m. UTC 
Update pmc_{read,write}_counter() to disconnect perf API because
passthrough PMU does not use host PMU on backend. Because of that
pmc->counter contains directly the actual value of the guest VM when set by
the host (VMM) side.

Signed-off-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
 arch/x86/kvm/pmu.c | 5 +++++
 arch/x86/kvm/pmu.h | 4 ++++
 2 files changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 41057d0122bd..3604cf467b34 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -322,6 +322,11 @@  static void pmc_update_sample_period(struct kvm_pmc *pmc)
 
 void pmc_write_counter(struct kvm_pmc *pmc, u64 val)
 {
+	if (pmc_to_pmu(pmc)->passthrough) {
+		pmc->counter = val;
+		return;
+	}
+
 	/*
 	 * Drop any unconsumed accumulated counts, the WRMSR is a write, not a
 	 * read-modify-write.  Adjust the counter value so that its value is
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 78a7f0c5f3ba..7e006cb61296 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -116,6 +116,10 @@  static inline u64 pmc_read_counter(struct kvm_pmc *pmc)
 {
 	u64 counter, enabled, running;
 
+	counter = pmc->counter;
+	if (pmc_to_pmu(pmc)->passthrough)
+		return counter & pmc_bitmask(pmc);
+
 	counter = pmc->counter + pmc->emulated_counter;
 
 	if (pmc->perf_event && !pmc->is_paused)