diff mbox series

[RFC,v2,2/5] i386/kvm: Support basic KVM PMU filter

Message ID 20250122090517.294083-3-zhao1.liu@intel.com (mailing list archive)
State New
Headers show
Series accel/kvm: Support KVM PMU filter | expand

Commit Message

Zhao Liu Jan. 22, 2025, 9:05 a.m. UTC
Filter PMU events with raw format in i386 code.

For i386, raw format indicates that the PMU event code is already
encoded according to the KVM ioctl requirements, and can be delivered
directly to KVM without additional encoding work.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
Changes since v1:
 * Stop check whether per-event actions are the same, as "action" has
   been a global parameter. (Dapeng)
 * Make pmu filter related functions return int in
   target/i386/kvm/kvm.c.
---
 include/system/kvm_int.h |   2 +
 target/i386/kvm/kvm.c    | 123 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+)
diff mbox series

Patch

diff --git a/include/system/kvm_int.h b/include/system/kvm_int.h
index 4de6106869b0..743fed29b17b 100644
--- a/include/system/kvm_int.h
+++ b/include/system/kvm_int.h
@@ -17,6 +17,7 @@ 
 #include "hw/boards.h"
 #include "hw/i386/topology.h"
 #include "io/channel-socket.h"
+#include "system/kvm-pmu.h"
 
 typedef struct KVMSlot
 {
@@ -166,6 +167,7 @@  struct KVMState
     uint16_t xen_gnttab_max_frames;
     uint16_t xen_evtchn_max_pirq;
     char *device;
+    KVMPMUFilter *pmu_filter;
 };
 
 void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 6c749d4ee812..b82adbed50f4 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -34,6 +34,7 @@ 
 #include "system/system.h"
 #include "system/hw_accel.h"
 #include "system/kvm_int.h"
+#include "system/kvm-pmu.h"
 #include "system/runstate.h"
 #include "kvm_i386.h"
 #include "../confidential-guest.h"
@@ -110,6 +111,7 @@  typedef struct {
 static void kvm_init_msrs(X86CPU *cpu);
 static int kvm_filter_msr(KVMState *s, uint32_t msr, QEMURDMSRHandler *rdmsr,
                           QEMUWRMSRHandler *wrmsr);
+static int kvm_filter_pmu_event(KVMState *s);
 
 const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
     KVM_CAP_INFO(SET_TSS_ADDR),
@@ -3346,6 +3348,14 @@  int kvm_arch_init(MachineState *ms, KVMState *s)
         }
     }
 
+    if (s->pmu_filter) {
+        ret = kvm_filter_pmu_event(s);
+        if (ret < 0) {
+            error_report("Could not set KVM PMU filter");
+            return ret;
+        }
+    }
+
     return 0;
 }
 
@@ -5942,6 +5952,82 @@  static int kvm_handle_wrmsr(X86CPU *cpu, struct kvm_run *run)
     g_assert_not_reached();
 }
 
+static bool kvm_config_pmu_event(KVMPMUFilter *filter,
+                                 struct kvm_pmu_event_filter *kvm_filter)
+{
+    KVMPMUFilterEventList *events;
+    KVMPMUFilterEvent *event;
+    uint64_t code;
+    int idx = 0;
+
+    kvm_filter->nevents = filter->nevents;
+    events = filter->events;
+    while (events) {
+        assert(idx < kvm_filter->nevents);
+
+        event = events->value;
+        switch (event->format) {
+        case KVM_PMU_EVENT_FMT_RAW:
+            code = event->u.raw.code;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+
+        kvm_filter->events[idx++] = code;
+        events = events->next;
+    }
+
+    return true;
+}
+
+static int kvm_install_pmu_event_filter(KVMState *s)
+{
+    struct kvm_pmu_event_filter *kvm_filter;
+    KVMPMUFilter *filter = s->pmu_filter;
+    int ret;
+
+    kvm_filter = g_malloc0(sizeof(struct kvm_pmu_event_filter) +
+                           filter->nevents * sizeof(uint64_t));
+
+    switch (filter->action) {
+    case KVM_PMU_FILTER_ACTION_ALLOW:
+        kvm_filter->action = KVM_PMU_EVENT_ALLOW;
+        break;
+    case KVM_PMU_FILTER_ACTION_DENY:
+        kvm_filter->action = KVM_PMU_EVENT_DENY;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    if (!kvm_config_pmu_event(filter, kvm_filter)) {
+        goto fail;
+    }
+
+    ret = kvm_vm_ioctl(s, KVM_SET_PMU_EVENT_FILTER, kvm_filter);
+    if (ret) {
+        error_report("KVM_SET_PMU_EVENT_FILTER fails (%s)", strerror(-ret));
+        goto fail;
+    }
+
+    g_free(kvm_filter);
+    return 0;
+fail:
+    g_free(kvm_filter);
+    return -EINVAL;
+}
+
+static int kvm_filter_pmu_event(KVMState *s)
+{
+    if (!kvm_vm_check_extension(s, KVM_CAP_PMU_EVENT_FILTER)) {
+        error_report("KVM PMU filter is not supported by Host.");
+        return -1;
+    }
+
+    return kvm_install_pmu_event_filter(s);
+}
+
 static bool has_sgx_provisioning;
 
 static bool __kvm_enable_sgx_provisioning(KVMState *s)
@@ -6537,6 +6623,35 @@  static void kvm_arch_set_xen_evtchn_max_pirq(Object *obj, Visitor *v,
     s->xen_evtchn_max_pirq = value;
 }
 
+static void kvm_arch_check_pmu_filter(const Object *obj, const char *name,
+                                      Object *child, Error **errp)
+{
+    KVMPMUFilter *filter = KVM_PMU_FILTER(child);
+    KVMPMUFilterEventList *events = filter->events;
+
+    if (!filter->nevents) {
+        error_setg(errp,
+                   "Empty KVM PMU filter.");
+        return;
+    }
+
+    while (events) {
+        KVMPMUFilterEvent *event = events->value;
+
+        switch (event->format) {
+        case KVM_PMU_EVENT_FMT_RAW:
+            break;
+        default:
+            error_setg(errp,
+                       "Unsupported PMU event format %s.",
+                       KVMPMUEventEncodeFmt_str(events->value->format));
+            return;
+        }
+
+        events = events->next;
+    }
+}
+
 void kvm_arch_accel_class_init(ObjectClass *oc)
 {
     object_class_property_add_enum(oc, "notify-vmexit", "NotifyVMexitOption",
@@ -6576,6 +6691,14 @@  void kvm_arch_accel_class_init(ObjectClass *oc)
                               NULL, NULL);
     object_class_property_set_description(oc, "xen-evtchn-max-pirq",
                                           "Maximum number of Xen PIRQs");
+
+    object_class_property_add_link(oc, "pmu-filter",
+                                   TYPE_KVM_PMU_FILTER,
+                                   offsetof(KVMState, pmu_filter),
+                                   kvm_arch_check_pmu_filter,
+                                   OBJ_PROP_LINK_STRONG);
+    object_class_property_set_description(oc, "pmu-filter",
+                                          "Set the KVM PMU filter");
 }
 
 void kvm_set_max_apic_id(uint32_t max_apic_id)