Hi Sebastian,
On 11/15/23 20:17, Sebastian Ott wrote:
Hi,
On Mon, 13 Nov 2023, Shaoqin Huang wrote:
+ ``pmu-filter={A,D}:start-end[;...]``
+ KVM implements pmu event filtering to prevent a guest from
being able to
+ sample certain events. It has the following format:
+
+ pmu-filter="{A,D}:start-end[;{A,D}:start-end...]"
+
+ The A means "allow" and D means "deny", start if the first event
of the
^
is
Thanks for point it out.
Also it should be stated that the first filter action defines if the whole
list is an allow or a deny list.
+static void kvm_arm_pmu_filter_init(CPUState *cs)
+{
+ struct kvm_pmu_event_filter filter;
+ struct kvm_device_attr attr = {
+ .group = KVM_ARM_VCPU_PMU_V3_CTRL,
+ .attr = KVM_ARM_VCPU_PMU_V3_FILTER,
+ };
+ KVMState *kvm_state = cs->kvm_state;
+ char *tmp;
+ char *str, act;
+
+ if (!kvm_state->kvm_pmu_filter)
+ return;
+
+ tmp = g_strdup(kvm_state->kvm_pmu_filter);
+
+ for (str = strtok(tmp, ";"); str != NULL; str = strtok(NULL, ";")) {
+ unsigned short start = 0, end = 0;
+
+ sscanf(str, "%c:%hx-%hx", &act, &start, &end);
+ if ((act != 'A' && act != 'D') || (!start && !end)) {
+ error_report("skipping invalid filter %s\n", str);
+ continue;
+ }
+
+ filter = (struct kvm_pmu_event_filter) {
+ .base_event = start,
+ .nevents = end - start + 1,
+ .action = act == 'A' ? KVM_PMU_EVENT_ALLOW :
+ KVM_PMU_EVENT_DENY,
+ };
+
+ attr.addr = (uint64_t)&filter;
That could move to the initialization of attr (the address of filter
doesn't change).
It looks better. Will change it.
+ if (!kvm_arm_set_device_attr(cs, &attr, "PMU Event Filter")) {
+ error_report("Failed to init PMU Event Filter\n");
+ abort();
+ }
+ }
+
+ g_free(tmp);
+}
+
void kvm_arm_pmu_init(CPUState *cs)
{
struct kvm_device_attr attr = {
.group = KVM_ARM_VCPU_PMU_V3_CTRL,
.attr = KVM_ARM_VCPU_PMU_V3_INIT,
};
+ static bool pmu_filter_init = false;
if (!ARM_CPU(cs)->has_pmu) {
return;
}
+ if (!pmu_filter_init) {
+ kvm_arm_pmu_filter_init(cs);
+ pmu_filter_init = true;
pmu_filter_init could move inside kvm_arm_pmu_filter_init() - maybe
together with a comment that this only needs to be called for 1 vcpu.
Good idea. Will do that.
Thanks,
Shaoqin
Thanks,
Sebastian
