[PATCH v5 11/12] KVM: selftests: aarch64: vPMU register test for implemented counters

Raghavendra Rao Ananta
2023-08-17T00:31:32Z

From: Reiji Watanabe <reijiw@google.com>

Add a new test case to the vpmu_counter_access test to check if PMU
registers or their bits for implemented counters on the vCPU are
readable/writable as expected, and can be programmed to count events.

Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
---
.../kvm/aarch64/vpmu_counter_access.c | 264 +++++++++++++++++-
1 file changed, 261 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
index d0afec07948ef..3a2cf38bb415d 100644
--- a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
+++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
@@ -5,7 +5,8 @@
* Copyright (c) 2022 Google LLC.
*
* This test checks if the guest can see the same number of the PMU event
- * counters (PMCR_EL0.N) that userspace sets.
+ * counters (PMCR_EL0.N) that userspace sets, and if the guest can access
+ * those counters.
* This test runs only when KVM_CAP_ARM_PMU_V3 is supported on the host.
*/
#include <kvm_util.h>
@@ -24,6 +25,251 @@ struct vpmu_vm {
int gic_fd;
};

+/* Read PMEVTCNTR<n>_EL0 through PMXEVCNTR_EL0 */
+static inline unsigned long read_sel_evcntr(int sel)
+{
+ write_sysreg(sel, pmselr_el0);
+ isb();
+ return read_sysreg(pmxevcntr_el0);
+}
+
+/* Write PMEVTCNTR<n>_EL0 through PMXEVCNTR_EL0 */
+static inline void write_sel_evcntr(int sel, unsigned long val)
+{
+ write_sysreg(sel, pmselr_el0);
+ isb();
+ write_sysreg(val, pmxevcntr_el0);
+ isb();
+}
+
+/* Read PMEVTYPER<n>_EL0 through PMXEVTYPER_EL0 */
+static inline unsigned long read_sel_evtyper(int sel)
+{
+ write_sysreg(sel, pmselr_el0);
+ isb();
+ return read_sysreg(pmxevtyper_el0);
+}
+
+/* Write PMEVTYPER<n>_EL0 through PMXEVTYPER_EL0 */
+static inline void write_sel_evtyper(int sel, unsigned long val)
+{
+ write_sysreg(sel, pmselr_el0);
+ isb();
+ write_sysreg(val, pmxevtyper_el0);
+ isb();
+}
+
+static inline void enable_counter(int idx)
+{
+ uint64_t v = read_sysreg(pmcntenset_el0);
+
+ write_sysreg(BIT(idx) | v, pmcntenset_el0);
+ isb();
+}
+
+static inline void disable_counter(int idx)
+{
+ uint64_t v = read_sysreg(pmcntenset_el0);
+
+ write_sysreg(BIT(idx) | v, pmcntenclr_el0);
+ isb();
+}
+
+static void pmu_disable_reset(void)
+{
+ uint64_t pmcr = read_sysreg(pmcr_el0);
+
+ /* Reset all counters, disabling them */
+ pmcr &= ~ARMV8_PMU_PMCR_E;
+ write_sysreg(pmcr | ARMV8_PMU_PMCR_P, pmcr_el0);
+ isb();
+}
+
+#define RETURN_READ_PMEVCNTRN(n) \
+ return read_sysreg(pmevcntr##n##_el0)
+static unsigned long read_pmevcntrn(int n)
+{
+ PMEVN_SWITCH(n, RETURN_READ_PMEVCNTRN);
+ return 0;
+}
+
+#define WRITE_PMEVCNTRN(n) \
+ write_sysreg(val, pmevcntr##n##_el0)
+static void write_pmevcntrn(int n, unsigned long val)
+{
+ PMEVN_SWITCH(n, WRITE_PMEVCNTRN);
+ isb();
+}
+
+#define READ_PMEVTYPERN(n) \
+ return read_sysreg(pmevtyper##n##_el0)
+static unsigned long read_pmevtypern(int n)
+{
+ PMEVN_SWITCH(n, READ_PMEVTYPERN);
+ return 0;
+}
+
+#define WRITE_PMEVTYPERN(n) \
+ write_sysreg(val, pmevtyper##n##_el0)
+static void write_pmevtypern(int n, unsigned long val)
+{
+ PMEVN_SWITCH(n, WRITE_PMEVTYPERN);
+ isb();
+}
+
+/*
+ * The pmc_accessor structure has pointers to PMEVT{CNTR,TYPER}<n>_EL0
+ * accessors that test cases will use. Each of the accessors will
+ * either directly reads/writes PMEVT{CNTR,TYPER}<n>_EL0
+ * (i.e. {read,write}_pmev{cnt,type}rn()), or reads/writes them through
+ * PMXEV{CNTR,TYPER}_EL0 (i.e. {read,write}_sel_ev{cnt,type}r()).
+ *
+ * This is used to test that combinations of those accessors provide
+ * the consistent behavior.
+ */
+struct pmc_accessor {
+ /* A function to be used to read PMEVTCNTR<n>_EL0 */
+ unsigned long (*read_cntr)(int idx);
+ /* A function to be used to write PMEVTCNTR<n>_EL0 */
+ void (*write_cntr)(int idx, unsigned long val);
+ /* A function to be used to read PMEVTYPER<n>_EL0 */
+ unsigned long (*read_typer)(int idx);
+ /* A function to be used to write PMEVTYPER<n>_EL0 */
+ void (*write_typer)(int idx, unsigned long val);
+};
+
+struct pmc_accessor pmc_accessors[] = {
+ /* test with all direct accesses */
+ { read_pmevcntrn, write_pmevcntrn, read_pmevtypern, write_pmevtypern },
+ /* test with all indirect accesses */
+ { read_sel_evcntr, write_sel_evcntr, read_sel_evtyper, write_sel_evtyper },
+ /* read with direct accesses, and write with indirect accesses */
+ { read_pmevcntrn, write_sel_evcntr, read_pmevtypern, write_sel_evtyper },
+ /* read with indirect accesses, and write with direct accesses */
+ { read_sel_evcntr, write_pmevcntrn, read_sel_evtyper, write_pmevtypern },
+};
+
+/*
+ * Convert a pointer of pmc_accessor to an index in pmc_accessors[],
+ * assuming that the pointer is one of the entries in pmc_accessors[].
+ */
+#define PMC_ACC_TO_IDX(acc) (acc - &pmc_accessors[0])
+
+#define GUEST_ASSERT_BITMAP_REG(regname, mask, set_expected) \
+{ \
+ uint64_t _tval = read_sysreg(regname); \
+ \
+ if (set_expected) \
+ GUEST_ASSERT_3((_tval & mask), _tval, mask, set_expected); \
+ else \
+ GUEST_ASSERT_3(!(_tval & mask), _tval, mask, set_expected);\
+}
+
+/*
+ * Check if @mask bits in {PMCNTEN,PMINTEN,PMOVS}{SET,CLR} registers
+ * are set or cleared as specified in @set_expected.
+ */
+static void check_bitmap_pmu_regs(uint64_t mask, bool set_expected)
+{
+ GUEST_ASSERT_BITMAP_REG(pmcntenset_el0, mask, set_expected);
+ GUEST_ASSERT_BITMAP_REG(pmcntenclr_el0, mask, set_expected);
+ GUEST_ASSERT_BITMAP_REG(pmintenset_el1, mask, set_expected);
+ GUEST_ASSERT_BITMAP_REG(pmintenclr_el1, mask, set_expected);
+ GUEST_ASSERT_BITMAP_REG(pmovsset_el0, mask, set_expected);
+ GUEST_ASSERT_BITMAP_REG(pmovsclr_el0, mask, set_expected);
+}
+
+/*
+ * Check if the bit in {PMCNTEN,PMINTEN,PMOVS}{SET,CLR} registers corresponding
+ * to the specified counter (@pmc_idx) can be read/written as expected.
+ * When @set_op is true, it tries to set the bit for the counter in
+ * those registers by writing the SET registers (the bit won't be set
+ * if the counter is not implemented though).
+ * Otherwise, it tries to clear the bits in the registers by writing
+ * the CLR registers.
+ * Then, it checks if the values indicated in the registers are as expected.
+ */
+static void test_bitmap_pmu_regs(int pmc_idx, bool set_op)
+{
+ uint64_t pmcr_n, test_bit = BIT(pmc_idx);
+ bool set_expected = false;
+
+ if (set_op) {
+ write_sysreg(test_bit, pmcntenset_el0);
+ write_sysreg(test_bit, pmintenset_el1);
+ write_sysreg(test_bit, pmovsset_el0);
+
+ /* The bit will be set only if the counter is implemented */
+ pmcr_n = FIELD_GET(ARMV8_PMU_PMCR_N, read_sysreg(pmcr_el0));
+ set_expected = (pmc_idx < pmcr_n) ? true : false;
+ } else {
+ write_sysreg(test_bit, pmcntenclr_el0);
+ write_sysreg(test_bit, pmintenclr_el1);
+ write_sysreg(test_bit, pmovsclr_el0);
+ }
+ check_bitmap_pmu_regs(test_bit, set_expected);
+}
+
+/*
+ * Tests for reading/writing registers for the (implemented) event counter
+ * specified by @pmc_idx.
+ */
+static void test_access_pmc_regs(struct pmc_accessor *acc, int pmc_idx)
+{
+ uint64_t write_data, read_data;
+
+ /* Disable all PMCs and reset all PMCs to zero. */
+ pmu_disable_reset();
+
+
+ /*
+ * Tests for reading/writing {PMCNTEN,PMINTEN,PMOVS}{SET,CLR}_EL1.
+ */
+
+ /* Make sure that the bit in those registers are set to 0 */
+ test_bitmap_pmu_regs(pmc_idx, false);
+ /* Test if setting the bit in those registers works */
+ test_bitmap_pmu_regs(pmc_idx, true);
+ /* Test if clearing the bit in those registers works */
+ test_bitmap_pmu_regs(pmc_idx, false);
+
+
+ /*
+ * Tests for reading/writing the event type register.
+ */
+
+ read_data = acc->read_typer(pmc_idx);
+ /*
+ * Set the event type register to an arbitrary value just for testing
+ * of reading/writing the register.
+ * ArmARM says that for the event from 0x0000 to 0x003F,
+ * the value indicated in the PMEVTYPER<n>_EL0.evtCount field is
+ * the value written to the field even when the specified event
+ * is not supported.
+ */
+ write_data = (ARMV8_PMU_EXCLUDE_EL1 | ARMV8_PMUV3_PERFCTR_INST_RETIRED);
+ acc->write_typer(pmc_idx, write_data);
+ read_data = acc->read_typer(pmc_idx);
+ GUEST_ASSERT_4(read_data == write_data,
+ pmc_idx, PMC_ACC_TO_IDX(acc), read_data, write_data);
+
+
+ /*
+ * Tests for reading/writing the event count register.
+ */
+
+ read_data = acc->read_cntr(pmc_idx);
+
+ /* The count value must be 0, as it is not used after the reset */
+ GUEST_ASSERT_3(read_data == 0, pmc_idx, acc, read_data);
+
+ write_data = read_data + pmc_idx + 0x12345;
+ acc->write_cntr(pmc_idx, write_data);
+ read_data = acc->read_cntr(pmc_idx);
+ GUEST_ASSERT_4(read_data == write_data,
+ pmc_idx, PMC_ACC_TO_IDX(acc), read_data, write_data);
+}
+
static void guest_sync_handler(struct ex_regs *regs)
{
uint64_t esr, ec;
@@ -36,11 +282,14 @@ static void guest_sync_handler(struct ex_regs *regs)
/*
* The guest is configured with PMUv3 with @expected_pmcr_n number of
* event counters.
- * Check if @expected_pmcr_n is consistent with PMCR_EL0.N.
+ * Check if @expected_pmcr_n is consistent with PMCR_EL0.N, and
+ * if reading/writing PMU registers for implemented counters can work
+ * as expected.
*/
static void guest_code(uint64_t expected_pmcr_n)
{
uint64_t pmcr, pmcr_n;
+ int i, pmc;

GUEST_ASSERT(expected_pmcr_n <= ARMV8_PMU_MAX_GENERAL_COUNTERS);

@@ -50,6 +299,15 @@ static void guest_code(uint64_t expected_pmcr_n)
/* Make sure that PMCR_EL0.N indicates the value userspace set */
GUEST_ASSERT_2(pmcr_n == expected_pmcr_n, pmcr_n, expected_pmcr_n);

+ /*
+ * Tests for reading/writing PMU registers for implemented counters.
+ * Use each combination of PMEVT{CNTR,TYPER}<n>_EL0 accessor functions.
+ */
+ for (i = 0; i < ARRAY_SIZE(pmc_accessors); i++) {
+ for (pmc = 0; pmc < pmcr_n; pmc++)
+ test_access_pmc_regs(&pmc_accessors[i], pmc);
+ }
+
GUEST_DONE();
}

@@ -121,7 +379,7 @@ static void run_vcpu(struct kvm_vcpu *vcpu, uint64_t pmcr_n)
vcpu_run(vcpu);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
- REPORT_GUEST_ASSERT_2(uc, "values:%#lx %#lx");
+ REPORT_GUEST_ASSERT_4(uc, "values:%#lx %#lx %#lx %#lx");
break;
case UCALL_DONE:
break;
--
2.41.0.694.ge786442a9b-goog