Hi Marc,
On 10.03.20 19:00, Marc Zyngier wrote:
On 2020-03-10 17:40, Auger Eric wrote:
Hi Marc,
On 3/10/20 12:03 PM, Marc Zyngier wrote:
Hi Eric,
On 2020-03-09 18:05, Auger Eric wrote:
Hi Marc,
On 3/9/20 1:48 PM, Marc Zyngier wrote:
It can be desirable to expose a PMU to a guest, and yet not want the
guest to be able to count some of the implemented events (because this
would give information on shared resources, for example.
For this, let's extend the PMUv3 device API, and offer a way to
setup a
bitmap of the allowed events (the default being no bitmap, and thus no
filtering).
Userspace can thus allow/deny ranges of event. The default policy
depends on the "polarity" of the first filter setup (default deny
if the
filter allows events, and default allow if the filter denies events).
This allows to setup exactly what is allowed for a given guest.
Note that although the ioctl is per-vcpu, the map of allowed events is
global to the VM (it can be setup from any vcpu until the vcpu PMU is
initialized).
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 6 +++
arch/arm64/include/uapi/asm/kvm.h | 16 ++++++
virt/kvm/arm/arm.c | 2 +
virt/kvm/arm/pmu.c | 84
+++++++++++++++++++++++++------
4 files changed, 92 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index 57fd46acd058..8e63c618688d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -91,6 +91,12 @@ struct kvm_arch {
* supported.
*/
bool return_nisv_io_abort_to_user;
+
+ /*
+ * VM-wide PMU filter, implemented as a bitmap and big enough
+ * for up to 65536 events
+ */
+ unsigned long *pmu_filter;
};
#define KVM_NR_MEM_OBJS 40
diff --git a/arch/arm64/include/uapi/asm/kvm.h
b/arch/arm64/include/uapi/asm/kvm.h
index ba85bb23f060..7b1511d6ce44 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -159,6 +159,21 @@ struct kvm_sync_regs {
struct kvm_arch_memory_slot {
};
+/*
+ * PMU filter structure. Describe a range of events with a particular
+ * action. To be used with KVM_ARM_VCPU_PMU_V3_FILTER.
+ */
+struct kvm_pmu_event_filter {
+ __u16 base_event;
+ __u16 nevents;
+
+#define KVM_PMU_EVENT_ALLOW 0
+#define KVM_PMU_EVENT_DENY 1
+
+ __u8 action;
+ __u8 pad[3];
+};
+
/* for KVM_GET/SET_VCPU_EVENTS */
struct kvm_vcpu_events {
struct {
@@ -329,6 +344,7 @@ struct kvm_vcpu_events {
#define KVM_ARM_VCPU_PMU_V3_CTRL 0
#define KVM_ARM_VCPU_PMU_V3_IRQ 0
#define KVM_ARM_VCPU_PMU_V3_INIT 1
+#define KVM_ARM_VCPU_PMU_V3_FILTER 2
#define KVM_ARM_VCPU_TIMER_CTRL 1
#define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index eda7b624eab8..8d849ac88a44 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -164,6 +164,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
free_percpu(kvm->arch.last_vcpu_ran);
kvm->arch.last_vcpu_ran = NULL;
+ bitmap_free(kvm->arch.pmu_filter);
+
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
if (kvm->vcpus[i]) {
kvm_vcpu_destroy(kvm->vcpus[i]);
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index f0d0312c0a55..9f0fd0224d5b 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -579,10 +579,19 @@ static void kvm_pmu_create_perf_event(struct
kvm_vcpu *vcpu, u64 select_idx)
kvm_pmu_stop_counter(vcpu, pmc);
eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
+ if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
+ eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
nit:
if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
else
eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
You don't like it? ;-)
? eventset set only once instead of 2 times
The compiler does the right thing, but sore, I'll change it.
I haven't seen a v3 follow-up after this. Do you happen to have that
somewhere in a local branch and just need to send it out or would you
prefer if I pick up v2 and address the comments?
Thanks,
Alex
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
