On Mon, 9 Oct 2023, Raghavendra Rao Ananta wrote:
+static void guest_code(uint64_t expected_pmcr_n)
+{
+ uint64_t pmcr, pmcr_n;
+
+ __GUEST_ASSERT(expected_pmcr_n <= ARMV8_PMU_MAX_GENERAL_COUNTERS,
+ "Expected PMCR.N: 0x%lx; ARMv8 general counters: 0x%lx",
+ expected_pmcr_n, ARMV8_PMU_MAX_GENERAL_COUNTERS);
+
+ pmcr = read_sysreg(pmcr_el0);
+ pmcr_n = get_pmcr_n(pmcr);
+
+ /* Make sure that PMCR_EL0.N indicates the value userspace set */
+ __GUEST_ASSERT(pmcr_n == expected_pmcr_n,
+ "Expected PMCR.N: 0x%lx, PMCR.N: 0x%lx",
+ pmcr_n, expected_pmcr_n);
Expected vs read value is swapped.
Also, since the kernel has special handling for this, should we add a
test like below?
+static void immutable_test(void)
+{
+ struct kvm_vcpu *vcpu;
+ uint64_t sp, pmcr, pmcr_n;
+ struct kvm_vcpu_init init;
+
+ create_vpmu_vm(guest_code);
+
+ vcpu = vpmu_vm.vcpu;
+
+ /* Save the initial sp to restore them later to run the guest again */
+ vcpu_get_reg(vcpu, ARM64_CORE_REG(sp_el1), &sp);
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), &pmcr);
+ pmcr_n = get_pmcr_n(pmcr);
+
+ run_vcpu(vcpu, pmcr_n);
+
+ vm_ioctl(vpmu_vm.vm, KVM_ARM_PREFERRED_TARGET, &init);
+ init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
+ aarch64_vcpu_setup(vcpu, &init);
+ vcpu_init_descriptor_tables(vcpu);
+ vcpu_set_reg(vcpu, ARM64_CORE_REG(sp_el1), sp);
+ vcpu_set_reg(vcpu, ARM64_CORE_REG(regs.pc), (uint64_t)guest_code);
+
+ /* Update the PMCR_EL0.N after the VM ran once */
+ set_pmcr_n(&pmcr, 0);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0), pmcr);
+
+ /* Verify that the guest still gets the unmodified value */
+ run_vcpu(vcpu, pmcr_n);
+
+ destroy_vpmu_vm();
+}
