Re: [PATCH v4 14/18] KVM: arm64: selftests: Add host support for vGIC

[Oliver Upton]

Hi Raghu,

On Thu, Sep 09, 2021 at 01:38:14AM +0000, Raghavendra Rao Ananta wrote:
> Implement a simple library to perform vGIC-v3 setup
> from a host point of view. This includes creating a
> vGIC device, setting up distributor and redistributor
> attributes, and mapping the guest physical addresses.
> 
> The definition of REDIST_REGION_ATTR_ADDR is taken
> from aarch64/vgic_init test.
>

Consider dropping the macro from vgic_init.c and have it just include
vgic.h

> Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
> ---
>  tools/testing/selftests/kvm/Makefile          |  2 +-
>  .../selftests/kvm/include/aarch64/vgic.h      | 20 +++++++
>  .../testing/selftests/kvm/lib/aarch64/vgic.c  | 60 +++++++++++++++++++
>  3 files changed, 81 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/kvm/include/aarch64/vgic.h
>  create mode 100644 tools/testing/selftests/kvm/lib/aarch64/vgic.c
> 
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 5476a8ddef60..8342f65c1d96 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -35,7 +35,7 @@ endif
>  
>  LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/rbtree.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c
>  LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S
> -LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c lib/aarch64/gic.c lib/aarch64/gic_v3.c
> +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c lib/aarch64/gic.c lib/aarch64/gic_v3.c lib/aarch64/vgic.c
>  LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c
>  
>  TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
> diff --git a/tools/testing/selftests/kvm/include/aarch64/vgic.h b/tools/testing/selftests/kvm/include/aarch64/vgic.h
> new file mode 100644
> index 000000000000..3a776af958a0
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/aarch64/vgic.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * ARM Generic Interrupt Controller (GIC) host specific defines
> + */
> +
> +#ifndef SELFTEST_KVM_VGIC_H
> +#define SELFTEST_KVM_VGIC_H
> +
> +#include <linux/kvm.h>
> +
> +#define REDIST_REGION_ATTR_ADDR(count, base, flags, index) \
> +	(((uint64_t)(count) << 52) | \
> +	((uint64_t)((base) >> 16) << 16) | \
> +	((uint64_t)(flags) << 12) | \
> +	index)
> +
> +int vgic_v3_setup(struct kvm_vm *vm,
> +				uint64_t gicd_base_gpa, uint64_t gicr_base_gpa);
> +
> +#endif /* SELFTEST_KVM_VGIC_H */
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/vgic.c b/tools/testing/selftests/kvm/lib/aarch64/vgic.c
> new file mode 100644
> index 000000000000..2318912ab134
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/aarch64/vgic.c
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ARM Generic Interrupt Controller (GIC) v3 host support
> + */
> +
> +#include <linux/kvm.h>
> +#include <linux/sizes.h>
> +
> +#include "kvm_util.h"
> +#include "vgic.h"
> +
> +#define VGIC_V3_GICD_SZ		(SZ_64K)
> +#define VGIC_V3_GICR_SZ		(2 * SZ_64K)

These values are UAPI, consider dropping them in favor of the
definitions from asm/kvm.h

> +
> +/*
> + * vGIC-v3 default host setup
> + *
> + * Input args:
> + *	vm - KVM VM
> + *	gicd_base_gpa - Guest Physical Address of the Distributor region
> + *	gicr_base_gpa - Guest Physical Address of the Redistributor region
> + *
> + * Output args: None
> + *
> + * Return: GIC file-descriptor or negative error code upon failure
> + *
> + * The function creates a vGIC-v3 device and maps the distributor and
> + * redistributor regions of the guest. Since it depends on the number of
> + * vCPUs for the VM, it must be called after all the vCPUs have been created.

You could avoid the ordering dependency by explicitly taking nr_vcpus as
an arg. It would also avoid the need for 12/18.

Also note the required alignment on the GPA arguments you're taking.

> + */
> +int vgic_v3_setup(struct kvm_vm *vm,
> +		uint64_t gicd_base_gpa, uint64_t gicr_base_gpa)
> +{
> +	uint64_t redist_attr;
> +	int gic_fd, nr_vcpus;
> +	unsigned int nr_gic_pages;
> +
> +	nr_vcpus = vm_get_nr_vcpus(vm);
> +	TEST_ASSERT(nr_vcpus > 0, "Invalid number of CPUs: %u\n", nr_vcpus);
> +
> +	/* Distributor setup */
> +	gic_fd = kvm_create_device(vm, KVM_DEV_TYPE_ARM_VGIC_V3, false);
> +	kvm_device_access(gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> +			KVM_VGIC_V3_ADDR_TYPE_DIST, &gicd_base_gpa, true);
> +	nr_gic_pages = vm_calc_num_guest_pages(vm_get_mode(vm), VGIC_V3_GICD_SZ);
> +	virt_map(vm, gicd_base_gpa, gicd_base_gpa,  nr_gic_pages);
> +
> +	/* Redistributor setup */
> +	redist_attr = REDIST_REGION_ATTR_ADDR(nr_vcpus, gicr_base_gpa, 0, 0);
> +	kvm_device_access(gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> +			KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION, &redist_attr, true);
> +	nr_gic_pages = vm_calc_num_guest_pages(vm_get_mode(vm),
> +						VGIC_V3_GICR_SZ * nr_vcpus);
> +	virt_map(vm, gicr_base_gpa, gicr_base_gpa,  nr_gic_pages);
> +
> +	kvm_device_access(gic_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
> +				KVM_DEV_ARM_VGIC_CTRL_INIT, NULL, true);
> +
> +	return gic_fd;
> +}
> -- 
> 2.33.0.153.gba50c8fa24-goog
>