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KVM: x86: Add fixed counters to PMU filter

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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>
This commit is contained in:
Eric Hankland 2019-07-18 11:38:18 -07:00 committed by Paolo Bonzini
parent 88dddc11a8
commit 30cd860432
3 changed files with 35 additions and 12 deletions
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15
Documentation/virtual/kvm/api.txt
View File

@ -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

9
arch/x86/include/uapi/asm/kvm.h
View File

@ -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

23
arch/x86/kvm/pmu.c
View File

@ -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;
}