On Thu, Feb 01, 2024 at 09:56:50PM -0500, Shaoqin Huang wrote:
[...]
> diff --git a/tools/testing/selftests/kvm/include/aarch64/vpmu.h b/tools/testing/selftests/kvm/include/aarch64/vpmu.h
> new file mode 100644
> index 000000000000..0a56183644ee
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/aarch64/vpmu.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#include <kvm_util.h>
> +
> +#define GICD_BASE_GPA 0x8000000ULL
> +#define GICR_BASE_GPA 0x80A0000ULL
Shouldn't a standardized layout of the GIC frames go with the rest of
the GIC stuff?
> +/* Create a VM that has one vCPU with PMUv3 configured. */
> +struct vpmu_vm *create_vpmu_vm(void *guest_code)
> +{
> + struct kvm_vcpu_init init;
> + uint8_t pmuver;
> + uint64_t dfr0, irq = 23;
> + struct kvm_device_attr irq_attr = {
> + .group = KVM_ARM_VCPU_PMU_V3_CTRL,
> + .attr = KVM_ARM_VCPU_PMU_V3_IRQ,
> + .addr = (uint64_t)&irq,
> + };
> + struct kvm_device_attr init_attr = {
> + .group = KVM_ARM_VCPU_PMU_V3_CTRL,
> + .attr = KVM_ARM_VCPU_PMU_V3_INIT,
> + };
> + struct vpmu_vm *vpmu_vm;
> +
> + vpmu_vm = calloc(1, sizeof(*vpmu_vm));
> + TEST_ASSERT(vpmu_vm != NULL, "Insufficient Memory");
!vpmu_vm would be the normal way to test if a pointer is NULL.
> + memset(vpmu_vm, 0, sizeof(vpmu_vm));
What? man calloc would tell you that the returned object is already
zero-initalized.
> + vpmu_vm->vm = vm_create(1);
> + vm_init_descriptor_tables(vpmu_vm->vm);
> +
> + /* Create vCPU with PMUv3 */
> + vm_ioctl(vpmu_vm->vm, KVM_ARM_PREFERRED_TARGET, &init);
> + init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
> + vpmu_vm->vcpu = aarch64_vcpu_add(vpmu_vm->vm, 0, &init, guest_code);
> + vcpu_init_descriptor_tables(vpmu_vm->vcpu);
I extremely dislike that the VM is semi-configured by this helper.
You're still expecting the caller to actually install the exception
handler.
> + vpmu_vm->gic_fd = vgic_v3_setup(vpmu_vm->vm, 1, 64,
> + GICD_BASE_GPA, GICR_BASE_GPA);
> + __TEST_REQUIRE(vpmu_vm->gic_fd >= 0,
> + "Failed to create vgic-v3, skipping");
> +
> + /* Make sure that PMUv3 support is indicated in the ID register */
> + vcpu_get_reg(vpmu_vm->vcpu,
> + KVM_ARM64_SYS_REG(SYS_ID_AA64DFR0_EL1), &dfr0);
> + pmuver = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), dfr0);
> + TEST_ASSERT(pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF &&
> + pmuver >= ID_AA64DFR0_EL1_PMUVer_IMP,
> + "Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);
Not your code, but this assertion is meaningless. KVM does not advertise
an IMP_DEF PMU to guests.
> + /* Initialize vPMU */
> + vcpu_ioctl(vpmu_vm->vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);
> + vcpu_ioctl(vpmu_vm->vcpu, KVM_SET_DEVICE_ATTR, &init_attr);
Not your code, but these should be converted to kvm_device_attr_set()
calls.
Overall I'm somewhat tepid on the idea of the library being so
coarse-grained. It is usually more helpful to expose finer-grained
controls, like a helper that initializes the vPMU state for a
preexisting VM. That way the PMU code can more easily be composed with
other helpers in different tests.
--
Thanks,
Oliver
