KVM: x86: Add fixed counters to PMU filter

Updates KVM_CAP_PMU_EVENT_FILTER so it can also whitelist or blacklist
fixed counters.

Signed-off-by: Eric Hankland <ehankland@google.com>
[No need to check padding fields for zero. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2cd6250b289676ac0091f6a6299d33fabcd4d2f7..e54a3f51ddc514e60e736cd32c06ebde18110e88 100644 (file)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4090,17 +4090,22 @@ Parameters: struct kvm_pmu_event_filter (in)
 Returns: 0 on success, -1 on error
 
 struct kvm_pmu_event_filter {
-       __u32 action;
-       __u32 nevents;
-       __u64 events[0];
+       __u32 action;
+       __u32 nevents;
+       __u32 fixed_counter_bitmap;
+       __u32 flags;
+       __u32 pad[4];
+       __u64 events[0];
 };
 
 This ioctl restricts the set of PMU events that the guest can program.
 The argument holds a list of events which will be allowed or denied.
 The eventsel+umask of each event the guest attempts to program is compared
 against the events field to determine whether the guest should have access.
-This only affects general purpose counters; fixed purpose counters can
-be disabled by changing the perfmon CPUID leaf.
+The events field only controls general purpose counters; fixed purpose
+counters are controlled by the fixed_counter_bitmap.
+
+No flags are defined yet, the field must be zero.
 
 Valid values for 'action':
 #define KVM_PMU_EVENT_ALLOW 0

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index e901b0ab116ff81dc8a77237f68afb9fe5948d35..503d3f42da1676791d2c4f4a70bfad35743daf4c 100644 (file)
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -435,9 +435,12 @@ struct kvm_nested_state {
 
 /* for KVM_CAP_PMU_EVENT_FILTER */
 struct kvm_pmu_event_filter {
-       __u32 action;
-       __u32 nevents;
-       __u64 events[0];
+       __u32 action;
+       __u32 nevents;
+       __u32 fixed_counter_bitmap;
+       __u32 flags;
+       __u32 pad[4];
+       __u64 events[0];
 };
 
 #define KVM_PMU_EVENT_ALLOW 0

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index cedaa01ceb6fe0dfbcfce4ec26a680ccc290fbcf..46875bbd04198a1cbed9771765c6fa3db68dbcd1 100644 (file)
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -19,8 +19,8 @@
 #include "lapic.h"
 #include "pmu.h"
 
-/* This keeps the total size of the filter under 4k. */
-#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 63
+/* This is enough to filter the vast majority of currently defined events. */
+#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300
 
 /* NOTE:
  * - Each perf counter is defined as "struct kvm_pmc";
@@ -206,12 +206,24 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 {
        unsigned en_field = ctrl & 0x3;
        bool pmi = ctrl & 0x8;
+       struct kvm_pmu_event_filter *filter;
+       struct kvm *kvm = pmc->vcpu->kvm;
 
        pmc_stop_counter(pmc);
 
        if (!en_field || !pmc_is_enabled(pmc))
                return;
 
+       filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
+       if (filter) {
+               if (filter->action == KVM_PMU_EVENT_DENY &&
+                   test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
+                       return;
+               if (filter->action == KVM_PMU_EVENT_ALLOW &&
+                   !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
+                       return;
+       }
+
        pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
                              kvm_x86_ops->pmu_ops->find_fixed_event(idx),
                              !(en_field & 0x2), /* exclude user */
@@ -385,6 +397,9 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
            tmp.action != KVM_PMU_EVENT_DENY)
                return -EINVAL;
 
+       if (tmp.flags != 0)
+               return -EINVAL;
+
        if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS)
                return -E2BIG;
 
@@ -406,8 +421,8 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
        mutex_unlock(&kvm->lock);
 
        synchronize_srcu_expedited(&kvm->srcu);
-       r = 0;
+       r = 0;
 cleanup:
        kfree(filter);
-       return r;
+       return r;
 }