Add a vPMU test scenario to validate the userspace accesses for
the registers PM{C,I}NTEN{SET,CLR} and PMOVS{SET,CLR} to ensure
that KVM honors the architectural definitions of these registers
for a given PMCR.N.
Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
---
.../kvm/aarch64/vpmu_counter_access.c | 87 ++++++++++++++++++-
1 file changed, 86 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
index d5143925690db..2b697b144e677 100644
--- a/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
+++ b/tools/testing/selftests/kvm/aarch64/vpmu_counter_access.c
@@ -8,6 +8,8 @@
* counters (PMCR_EL0.N) that userspace sets, if the guest can access
* those counters, and if the guest is prevented from accessing any
* other counters.
+ * It also checks if the userspace accesses to the PMU regsisters honor the
+ * PMCR.N value that's set for the guest.
* This test runs only when KVM_CAP_ARM_PMU_V3 is supported on the host.
*/
#include <kvm_util.h>
@@ -20,6 +22,9 @@
/* The max number of the PMU event counters (excluding the cycle counter) */
#define ARMV8_PMU_MAX_GENERAL_COUNTERS (ARMV8_PMU_MAX_COUNTERS - 1)
+/* The cycle counter bit position that's common among the PMU registers */
+#define ARMV8_PMU_CYCLE_IDX 31
+
struct vpmu_vm {
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
@@ -28,6 +33,13 @@ struct vpmu_vm {
static struct vpmu_vm vpmu_vm;
+struct pmreg_sets {
+ uint64_t set_reg_id;
+ uint64_t clr_reg_id;
+};
+
+#define PMREG_SET(set, clr) {.set_reg_id = set, .clr_reg_id = clr}
+
static uint64_t get_pmcr_n(uint64_t pmcr)
{
return (pmcr >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK;
@@ -39,6 +51,15 @@ static void set_pmcr_n(uint64_t *pmcr, uint64_t pmcr_n)
*pmcr |= (pmcr_n << ARMV8_PMU_PMCR_N_SHIFT);
}
+static uint64_t get_counters_mask(uint64_t n)
+{
+ uint64_t mask = BIT(ARMV8_PMU_CYCLE_IDX);
+
+ if (n)
+ mask |= GENMASK(n - 1, 0);
+ return mask;
+}
+
/* Read PMEVTCNTR<n>_EL0 through PMXEVCNTR_EL0 */
static inline unsigned long read_sel_evcntr(int sel)
{
@@ -552,6 +573,68 @@ static void run_access_test(uint64_t pmcr_n)
destroy_vpmu_vm();
}
+static struct pmreg_sets validity_check_reg_sets[] = {
+ PMREG_SET(SYS_PMCNTENSET_EL0, SYS_PMCNTENCLR_EL0),
+ PMREG_SET(SYS_PMINTENSET_EL1, SYS_PMINTENCLR_EL1),
+ PMREG_SET(SYS_PMOVSSET_EL0, SYS_PMOVSCLR_EL0),
+};
+
+/*
+ * Create a VM, and check if KVM handles the userspace accesses of
+ * the PMU register sets in @validity_check_reg_sets[] correctly.
+ */
+static void run_pmregs_validity_test(uint64_t pmcr_n)
+{
+ int i;
+ struct kvm_vcpu *vcpu;
+ uint64_t set_reg_id, clr_reg_id, reg_val;
+ uint64_t valid_counters_mask, max_counters_mask;
+
+ test_create_vpmu_vm_with_pmcr_n(pmcr_n, false);
+ vcpu = vpmu_vm.vcpu;
+
+ valid_counters_mask = get_counters_mask(pmcr_n);
+ max_counters_mask = get_counters_mask(ARMV8_PMU_MAX_COUNTERS);
+
+ for (i = 0; i < ARRAY_SIZE(validity_check_reg_sets); i++) {
+ set_reg_id = validity_check_reg_sets[i].set_reg_id;
+ clr_reg_id = validity_check_reg_sets[i].clr_reg_id;
+
+ /*
+ * Test if the 'set' and 'clr' variants of the registers
+ * are initialized based on the number of valid counters.
+ */
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(set_reg_id), ®_val);
+ TEST_ASSERT((reg_val & (~valid_counters_mask)) == 0,
+ "Initial read of set_reg: 0x%llx has unimplemented counters enabled: 0x%lx\n",
+ KVM_ARM64_SYS_REG(set_reg_id), reg_val);
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(clr_reg_id), ®_val);
+ TEST_ASSERT((reg_val & (~valid_counters_mask)) == 0,
+ "Initial read of clr_reg: 0x%llx has unimplemented counters enabled: 0x%lx\n",
+ KVM_ARM64_SYS_REG(clr_reg_id), reg_val);
+
+ /*
+ * Using the 'set' variant, force-set the register to the
+ * max number of possible counters and test if KVM discards
+ * the bits for unimplemented counters as it should.
+ */
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(set_reg_id), max_counters_mask);
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(set_reg_id), ®_val);
+ TEST_ASSERT((reg_val & (~valid_counters_mask)) == 0,
+ "Read of set_reg: 0x%llx has unimplemented counters enabled: 0x%lx\n",
+ KVM_ARM64_SYS_REG(set_reg_id), reg_val);
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(clr_reg_id), ®_val);
+ TEST_ASSERT((reg_val & (~valid_counters_mask)) == 0,
+ "Read of clr_reg: 0x%llx has unimplemented counters enabled: 0x%lx\n",
+ KVM_ARM64_SYS_REG(clr_reg_id), reg_val);
+ }
+
+ destroy_vpmu_vm();
+}
+
/*
* Create a guest with one vCPU, and attempt to set the PMCR_EL0.N for
* the vCPU to @pmcr_n, which is larger than the host value.
@@ -586,8 +669,10 @@ int main(void)
TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
pmcr_n = get_pmcr_n_limit();
- for (i = 0; i <= pmcr_n; i++)
+ for (i = 0; i <= pmcr_n; i++) {
run_access_test(i);
+ run_pmregs_validity_test(i);
+ }
for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
run_error_test(i);
--
2.42.0.655.g421f12c284-goog
