@@ -9,7 +9,8 @@
* 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.
+ * PMCR.N value that's set for the guest and if these accesses are immutable
+ * after KVM has run once.
* This test runs only when KVM_CAP_ARM_PMU_V3 is supported on the host.
*/
#include <kvm_util.h>
@@ -648,6 +649,48 @@ static void run_error_test(uint64_t pmcr_n)
destroy_vpmu_vm();
}
+static uint64_t immutable_regs[] = {
+ SYS_PMCR_EL0,
+ SYS_PMCNTENSET_EL0,
+ SYS_PMCNTENCLR_EL0,
+ SYS_PMINTENSET_EL1,
+ SYS_PMINTENCLR_EL1,
+ SYS_PMOVSSET_EL0,
+ SYS_PMOVSCLR_EL0,
+};
+
+/*
+ * Create a guest with one vCPU, run it, and then make an attempt to update
+ * the registers in @immutable_regs[] (with their complements). KVM shouldn't
+ * allow updating these registers once vCPU starts running. Hence, the test
+ * fails if that's not the case.
+ */
+static void run_immutable_test(uint64_t pmcr_n)
+{
+ int i;
+ struct kvm_vcpu *vcpu;
+ uint64_t reg_id, reg_val, reg_val_orig;
+
+ create_vpmu_vm(guest_code);
+ vcpu = vpmu_vm.vcpu;
+
+ run_vcpu(vcpu, pmcr_n);
+
+ for (i = 0; i < ARRAY_SIZE(immutable_regs); i++) {
+ reg_id = immutable_regs[i];
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(reg_id), ®_val_orig);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(reg_id), ~reg_val_orig);
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(reg_id), ®_val);
+
+ TEST_ASSERT(reg_val == reg_val_orig,
+ "Register 0x%llx value updated after vCPU run: 0x%lx; expected: 0x%lx\n",
+ KVM_ARM64_SYS_REG(reg_id), reg_val, reg_val_orig);
+ }
+
+ destroy_vpmu_vm();
+}
+
/*
* Return the default number of implemented PMU event counters excluding
* the cycle counter (i.e. PMCR_EL0.N value) for the guest.
@@ -677,5 +720,7 @@ int main(void)
for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
run_error_test(i);
+ run_immutable_test(pmcr_n);
+
return 0;
}
KVM marks some of the vPMU registers as immutable to userspace once the vCPU has started running. Add a test scenario to check this behavior. Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> --- .../kvm/aarch64/vpmu_counter_access.c | 47 ++++++++++++++++++- 1 file changed, 46 insertions(+), 1 deletion(-)