Re: [PATCH] KVM: x86: Add fixed counters to PMU filter

From: Wei Wang
Date: Fri Jul 19 2019 - 04:26:28 EST


On 07/19/2019 02:38 AM, Eric Hankland wrote:
From: ehankland <ehankland@xxxxxxxxxx>

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

Signed-off-by: ehankland <ehankland@xxxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 13 ++++++++-----
arch/x86/include/uapi/asm/kvm.h | 9 ++++++---
arch/x86/kvm/pmu.c | 30 +++++++++++++++++++++++++-----
3 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2cd6250b2896..96bcf1aa1931 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4090,17 +4090,20 @@ 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.
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 e901b0ab116f..503d3f42da16 100644
--- 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 aa5a2597305a..ae5cd1b02086 100644
--- 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 +206,25 @@ 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;
+

unnecessary white space here, other part looks good to me.

Reviewed-by: Wei Wang <wei.w.wang@xxxxxxxxx>

Best,
Wei