diff options
| author | Eric Hankland <ehankland@google.com> | 2019-07-10 18:25:15 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-11 15:08:28 +0200 |
| commit | 66bb8a065f5aedd4551d8d3fbce582972f65c2e1 (patch) | |
| tree | e91f4895073a3f406a02037637d8ac27ee5c4d9b /Documentation | |
| parent | cdc238eb72f6b94b6c33b98c07b9fc3ac5e57b18 (diff) | |
KVM: x86: PMU Event Filter
Some events can provide a guest with information about other guests or the
host (e.g. L3 cache stats); providing the capability to restrict access
to a "safe" set of events would limit the potential for the PMU to be used
in any side channel attacks. This change introduces a new VM ioctl that
sets an event filter. If the guest attempts to program a counter for
any blacklisted or non-whitelisted event, the kernel counter won't be
created, so any RDPMC/RDMSR will show 0 instances of that event.
Signed-off-by: Eric Hankland <ehankland@google.com>
[Lots of changes. All remaining bugs are probably mine. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 91fd86fcc49f..38b0d4451a24 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -4065,6 +4065,32 @@ KVM_ARM_VCPU_FINALIZE call. See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization using this ioctl. +4.120 KVM_SET_PMU_EVENT_FILTER + +Capability: KVM_CAP_PMU_EVENT_FILTER +Architectures: x86 +Type: vm ioctl +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]; +}; + +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. + +Valid values for 'action': +#define KVM_PMU_EVENT_ALLOW 0 +#define KVM_PMU_EVENT_DENY 1 + + 5. The kvm_run structure ------------------------ |