[REPOST PATCH 08/16] selftests: KVM: aarch64: Consider PMU event filters for VM creation

Raghavendra Rao Ananta
2023-02-15T01:08:04Z

Accept a list of KVM PMU event filters as an argument while creating
a VM via create_vpmu_vm(). Upcoming patches would leverage this to
test the event filters' functionality.

No functional change intended.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
---
.../testing/selftests/kvm/aarch64/vpmu_test.c | 64 +++++++++++++++++--
1 file changed, 60 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_test.c b/tools/testing/selftests/kvm/aarch64/vpmu_test.c
index 15aebc7d7dc94..2b3a4fa3afa9c 100644
--- a/tools/testing/selftests/kvm/aarch64/vpmu_test.c
+++ b/tools/testing/selftests/kvm/aarch64/vpmu_test.c
@@ -15,10 +15,14 @@
#include <vgic.h>
#include <asm/perf_event.h>
#include <linux/bitfield.h>
+#include <linux/bitmap.h>

/* The max number of the PMU event counters (excluding the cycle counter) */
#define ARMV8_PMU_MAX_GENERAL_COUNTERS (ARMV8_PMU_MAX_COUNTERS - 1)

+/* The max number of event numbers that's supported */
+#define ARMV8_PMU_MAX_EVENTS 64
+
/*
* The macros and functions below for reading/writing PMEV{CNTR,TYPER}<n>_EL0
* were basically copied from arch/arm64/kernel/perf_event.c.
@@ -224,6 +228,8 @@ struct pmc_accessor pmc_accessors[] = {
{ read_sel_evcntr, write_pmevcntrn, read_sel_evtyper, write_pmevtypern },
};

+#define MAX_EVENT_FILTERS_PER_VM 10
+
#define INVALID_EC (-1ul)
uint64_t expected_ec = INVALID_EC;
uint64_t op_end_addr;
@@ -232,6 +238,7 @@ struct vpmu_vm {
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
int gic_fd;
+ unsigned long *pmu_filter;
};

enum test_stage {
@@ -541,8 +548,51 @@ static void guest_code(void)
#define GICD_BASE_GPA 0x8000000ULL
#define GICR_BASE_GPA 0x80A0000ULL

+static unsigned long *
+set_event_filters(struct kvm_vcpu *vcpu, struct kvm_pmu_event_filter *pmu_event_filters)
+{
+ int j;
+ unsigned long *pmu_filter;
+ struct kvm_device_attr filter_attr = {
+ .group = KVM_ARM_VCPU_PMU_V3_CTRL,
+ .attr = KVM_ARM_VCPU_PMU_V3_FILTER,
+ };
+
+ /*
+ * Setting up of the bitmap is similar to what KVM does.
+ * If the first filter denys an event, default all the others to allow, and vice-versa.
+ */
+ pmu_filter = bitmap_zalloc(ARMV8_PMU_MAX_EVENTS);
+ TEST_ASSERT(pmu_filter, "Failed to allocate the pmu_filter");
+
+ if (pmu_event_filters[0].action == KVM_PMU_EVENT_DENY)
+ bitmap_fill(pmu_filter, ARMV8_PMU_MAX_EVENTS);
+
+ for (j = 0; j < MAX_EVENT_FILTERS_PER_VM; j++) {
+ struct kvm_pmu_event_filter *pmu_event_filter = &pmu_event_filters[j];
+
+ if (!pmu_event_filter->nevents)
+ break;
+
+ pr_debug("Applying event filter:: event: 0x%x; action: %s\n",
+ pmu_event_filter->base_event,
+ pmu_event_filter->action == KVM_PMU_EVENT_ALLOW ? "ALLOW" : "DENY");
+
+ filter_attr.addr = (uint64_t) pmu_event_filter;
+ vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &filter_attr);
+
+ if (pmu_event_filter->action == KVM_PMU_EVENT_ALLOW)
+ __set_bit(pmu_event_filter->base_event, pmu_filter);
+ else
+ __clear_bit(pmu_event_filter->base_event, pmu_filter);
+ }
+
+ return pmu_filter;
+}
+
/* Create a VM that has one vCPU with PMUv3 configured. */
-static struct vpmu_vm *create_vpmu_vm(void *guest_code)
+static struct vpmu_vm *
+create_vpmu_vm(void *guest_code, struct kvm_pmu_event_filter *pmu_event_filters)
{
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
@@ -586,6 +636,9 @@ static struct vpmu_vm *create_vpmu_vm(void *guest_code)
"Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);

/* Initialize vPMU */
+ if (pmu_event_filters)
+ vpmu_vm->pmu_filter = set_event_filters(vcpu, pmu_event_filters);
+
vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);
vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &init_attr);

@@ -594,6 +647,8 @@ static struct vpmu_vm *create_vpmu_vm(void *guest_code)

static void destroy_vpmu_vm(struct vpmu_vm *vpmu_vm)
{
+ if (vpmu_vm->pmu_filter)
+ bitmap_free(vpmu_vm->pmu_filter);
close(vpmu_vm->gic_fd);
kvm_vm_free(vpmu_vm->vm);
free(vpmu_vm);
@@ -631,7 +686,7 @@ static void run_counter_access_test(uint64_t pmcr_n)
guest_data.expected_pmcr_n = pmcr_n;

pr_debug("Test with pmcr_n %lu\n", pmcr_n);
- vpmu_vm = create_vpmu_vm(guest_code);
+ vpmu_vm = create_vpmu_vm(guest_code, NULL);
vcpu = vpmu_vm->vcpu;

/* Save the initial sp to restore them later to run the guest again */
@@ -676,7 +731,7 @@ static void run_counter_access_error_test(uint64_t pmcr_n)
guest_data.expected_pmcr_n = pmcr_n;

pr_debug("Error test with pmcr_n %lu (larger than the host)\n", pmcr_n);
- vpmu_vm = create_vpmu_vm(guest_code);
+ vpmu_vm = create_vpmu_vm(guest_code, NULL);
vcpu = vpmu_vm->vcpu;

/* Update the PMCR_EL0.N with @pmcr_n */
@@ -719,9 +774,10 @@ static uint64_t get_pmcr_n_limit(void)
struct vpmu_vm *vpmu_vm;
uint64_t pmcr;

- vpmu_vm = create_vpmu_vm(guest_code);
+ vpmu_vm = create_vpmu_vm(guest_code, NULL);
vcpu_get_reg(vpmu_vm->vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), &pmcr);
destroy_vpmu_vm(vpmu_vm);
+
return FIELD_GET(ARMV8_PMU_PMCR_N, pmcr);
}

--
2.39.1.581.gbfd45094c4-goog