Re: [PATCH v3 11/19] target/riscv: introduce KVM AccelCPUClass

[Alistair Francis]

On Wed, Sep 20, 2023 at 9:23 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> Add a KVM accelerator class like we did with TCG. The difference is
> that, at least for now, we won't be using a realize() implementation for
> this accelerator.
>
> We'll start by assiging kvm_riscv_cpu_add_kvm_properties(), renamed to
> kvm_cpu_instance_init(), as a 'cpu_instance_init' implementation. Change
> riscv_cpu_post_init() to invoke accel_cpu_instance_init(), which will go
> through the 'cpu_instance_init' impl of the current acceleration (if
> available) and execute it. The end result is that the KVM initial setup,
> i.e. starting registers and adding its specific properties, will be done
> via this hook.
>
> Add a 'tcg_enabled()' condition in riscv_cpu_post_init() to avoid
> calling riscv_cpu_add_user_properties() when running KVM. We'll remove
> this condition when the TCG accel class get its own 'cpu_instance_init'
> implementation.
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu.c       |  8 +++-----
>  target/riscv/kvm.c       | 26 ++++++++++++++++++++++++--
>  target/riscv/kvm_riscv.h |  1 -
>  3 files changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 50be127f36..c8a19be1af 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1219,7 +1219,9 @@ static bool riscv_cpu_has_user_properties(Object 
> *cpu_obj)
>
>  static void riscv_cpu_post_init(Object *obj)
>  {
> -    if (riscv_cpu_has_user_properties(obj)) {
> +    accel_cpu_instance_init(CPU(obj));
> +
> +    if (tcg_enabled() && riscv_cpu_has_user_properties(obj)) {
>          riscv_cpu_add_user_properties(obj);
>      }
>
> @@ -1589,10 +1591,6 @@ static void riscv_cpu_add_multiext_prop_array(Object 
> *obj,
>  static void riscv_cpu_add_user_properties(Object *obj)
>  {
>  #ifndef CONFIG_USER_ONLY
> -    if (kvm_enabled()) {
> -        kvm_riscv_cpu_add_kvm_properties(obj);
> -        return;
> -    }
>      riscv_add_satp_mode_properties(obj);
>  #endif
>
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index e5e957121f..606fdab223 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -31,6 +31,7 @@
>  #include "sysemu/kvm_int.h"
>  #include "cpu.h"
>  #include "trace.h"
> +#include "hw/core/accel-cpu.h"
>  #include "hw/pci/pci.h"
>  #include "exec/memattrs.h"
>  #include "exec/address-spaces.h"
> @@ -1318,8 +1319,9 @@ void kvm_riscv_aia_create(MachineState *machine, 
> uint64_t group_shift,
>      kvm_msi_via_irqfd_allowed = kvm_irqfds_enabled();
>  }
>
> -void kvm_riscv_cpu_add_kvm_properties(Object *obj)
> +static void kvm_cpu_instance_init(CPUState *cs)
>  {
> +    Object *obj = OBJECT(RISCV_CPU(cs));
>      DeviceState *dev = DEVICE(obj);
>
>      riscv_init_user_properties(obj);
> @@ -1331,7 +1333,7 @@ void kvm_riscv_cpu_add_kvm_properties(Object *obj)
>      riscv_cpu_add_kvm_unavail_prop_array(obj, riscv_cpu_experimental_exts);
>
>      for (Property *prop = riscv_cpu_options; prop && prop->name; prop++) {
> -        /* Check if KVM created the property already */
> +        /* Check if we have a specific KVM handler for the option */
>          if (object_property_find(obj, prop->name)) {
>              continue;
>          }
> @@ -1339,6 +1341,26 @@ void kvm_riscv_cpu_add_kvm_properties(Object *obj)
>      }
>  }
>
> +static void kvm_cpu_accel_class_init(ObjectClass *oc, void *data)
> +{
> +    AccelCPUClass *acc = ACCEL_CPU_CLASS(oc);
> +
> +    acc->cpu_instance_init = kvm_cpu_instance_init;
> +}
> +
> +static const TypeInfo kvm_cpu_accel_type_info = {
> +    .name = ACCEL_CPU_NAME("kvm"),
> +
> +    .parent = TYPE_ACCEL_CPU,
> +    .class_init = kvm_cpu_accel_class_init,
> +    .abstract = true,
> +};
> +static void kvm_cpu_accel_register_types(void)
> +{
> +    type_register_static(&kvm_cpu_accel_type_info);
> +}
> +type_init(kvm_cpu_accel_register_types);
> +
>  static void riscv_host_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> diff --git a/target/riscv/kvm_riscv.h b/target/riscv/kvm_riscv.h
> index da9630c4af..8329cfab82 100644
> --- a/target/riscv/kvm_riscv.h
> +++ b/target/riscv/kvm_riscv.h
> @@ -19,7 +19,6 @@
>  #ifndef QEMU_KVM_RISCV_H
>  #define QEMU_KVM_RISCV_H
>
> -void kvm_riscv_cpu_add_kvm_properties(Object *obj);
>  void kvm_riscv_reset_vcpu(RISCVCPU *cpu);
>  void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level);
>  void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
> --
> 2.41.0
>
>