[PATCH v5 0/3] Register accel-$cpu_type for all targets

[PATCH v5 0/3] Register accel-$cpu_type for all targets

[Yonggang Luo]

A multi-target system binary links more than one target.
accel_cpu_register_type() creates the abstract parent accel-$cpu_type for each
target that has an AccelCPU subclass. ARM, i386, RISC-V, and PowerPC call it.
Other targets have no such subclass, and machine init skips a missing class.

test-multi-target already instantiates every QOM type, so this series adds no
parent check.

This is an alternative to gating accelerator CPU types with is_available. The
RISC-V TCG and KVM gates are reverted here as redundant.

v4: https://lore.kernel.org/qemu-devel/20261105183310.1614-1-luoyonggang@gmail.com/

Changes v4 -> v5:

- Drop test_accel_cpu_parent(). test_qom_types_are_unique() already instantiates
  every QOM type

Yonggang Luo (3):
  accel: register CPU parent only for AccelCPU subclasses
  Revert "target/riscv/kvm: restrict kvm-accel-riscv-cpu to riscv
    targets"
  Revert "target/riscv/tcg: restrict tcg-accel-riscv-cpu to riscv
    targets"

 accel/accel-common.c       | 6 ++----
 include/accel/accel-cpu.h  | 2 ++
 target/arm/cpu.c           | 2 ++
 target/i386/cpu.c          | 2 ++
 target/ppc/cpu_init.c      | 2 ++
 target/riscv/cpu.c         | 8 ++++++++
 target/riscv/kvm/kvm-cpu.c | 2 --
 target/riscv/tcg/tcg-cpu.c | 1 -
 8 files changed, 18 insertions(+), 7 deletions(-)

-- 
2.55.0.windows.3

[PATCH v5 1/3] accel: register CPU parent only for AccelCPU subclasses

[Yonggang Luo]

accel_cpu_register_type() creates the abstract parent
accel-<cpu type>. A subclass names that parent, and
type_initialize() aborts when the parent is missing. The old
type_init registered only target_cpu_type(), which is one name
in a multi-target process. Call the helper from the CPU type
init of each target that has an AccelCPU subclass.

ARM calls it because whpx-common.c parents accel-arm-cpu on
aarch64-softmmu. i386 calls it for TCG, KVM, HVF, NVMM, and
MSHV. i386-softmmu and x86_64-softmmu each pass their own
CPU_RESOLVING_TYPE, so WHPX on x86_64-softmmu finds
accel-x86_64-cpu. RISC-V calls it for TCG and KVM. PowerPC
calls it for KVM.

Other targets have no AccelCPU subclass. Machine init looks up
tcg-accel-<cpu type> or kvm-accel-<cpu type> and skips a missing
class, so those targets do not need the parent.

No extra tests is needed, as these QOM types already be
tested by the existing logic instantiating all QOM types.

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
---
 accel/accel-common.c      | 6 ++----
 include/accel/accel-cpu.h | 2 ++
 target/arm/cpu.c          | 2 ++
 target/i386/cpu.c         | 2 ++
 target/ppc/cpu_init.c     | 2 ++
 target/riscv/cpu.c        | 8 ++++++++
 6 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/accel/accel-common.c b/accel/accel-common.c
index 00a400243f..441d1b77fa 100644
--- a/accel/accel-common.c
+++ b/accel/accel-common.c
@@ -130,9 +130,9 @@ static const TypeInfo accel_types[] = {
 
 DEFINE_TYPES(accel_types)
 
-static void register_accel_target_type(void)
+void accel_cpu_register_type(const char *cpu_type)
 {
-    g_autofree char *name = g_strconcat("accel-", target_cpu_type(), NULL);
+    g_autofree char *name = g_strconcat("accel-", cpu_type, NULL);
     const TypeInfo accel_cpu_type = {
         .name = name,
         .parent = TYPE_OBJECT,
@@ -142,5 +142,3 @@ static void register_accel_target_type(void)
 
     type_register_static(&accel_cpu_type);
 }
-
-type_init(register_accel_target_type);
diff --git a/include/accel/accel-cpu.h b/include/accel/accel-cpu.h
index 9e7eede7c3..2fdb64d2ae 100644
--- a/include/accel/accel-cpu.h
+++ b/include/accel/accel-cpu.h
@@ -20,4 +20,6 @@ typedef struct AccelCPUClass {
     bool (*cpu_target_realize)(CPUState *cpu, Error **errp);
 } AccelCPUClass;
 
+void accel_cpu_register_type(const char *cpu_type);
+
 #endif /* ACCEL_CPU_H */
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 71681447b2..725f1f3a5f 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -28,6 +28,7 @@
 #include "qemu/module.h"
 #include "qapi/error.h"
 #include "cpu.h"
+#include "accel/accel-cpu.h"
 #ifdef CONFIG_TCG
 #include "exec/translation-block.h"
 #include "accel/tcg/cpu-ops.h"
@@ -2753,6 +2754,7 @@ static const TypeInfo arm_cpu_type_info = {
 
 static void arm_cpu_register_types(void)
 {
+    accel_cpu_register_type(CPU_RESOLVING_TYPE);
     type_register_static(&arm_cpu_type_info);
 }
 
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index eab0d5a4d4..31b09e6f8e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -23,6 +23,7 @@
 #include "qemu/qemu-print.h"
 #include "qemu/hw-version.h"
 #include "cpu.h"
+#include "accel/accel-cpu.h"
 #include "tcg/helper-tcg.h"
 #include "exec/translation-block.h"
 #include "system/hvf.h"
@@ -11093,6 +11094,7 @@ static void x86_cpu_register_types(void)
 {
     int i;
 
+    accel_cpu_register_type(CPU_RESOLVING_TYPE);
     type_register_static(&x86_cpu_type_info);
     for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
         x86_register_cpudef_types(&builtin_x86_defs[i]);
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 7f3036d903..fe3f2549b7 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -43,6 +43,7 @@
 #include "exec/page-protection.h"
 #include "exec/watchpoint.h"
 #include "helper_regs.h"
+#include "accel/accel-cpu.h"
 #include "internal.h"
 #include "spr_common.h"
 #include "power8-pmu.h"
@@ -7589,6 +7590,7 @@ static const TypeInfo ppc_vhyp_type_info = {
 
 static void ppc_cpu_register_types(void)
 {
+    accel_cpu_register_type(CPU_RESOLVING_TYPE);
     type_register_static(&ppc_cpu_type_info);
 #ifndef CONFIG_USER_ONLY
     type_register_static(&ppc_vhyp_type_info);
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 362e561809..10e24f20e8 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -25,6 +25,7 @@
 #include "qemu/guest-random.h"
 #include "qemu/atomic.h"
 #include "cpu.h"
+#include "accel/accel-cpu.h"
 #include "cpu_vendorid.h"
 #include "target/riscv/tcg/csr.h"
 #include "internals.h"
@@ -3931,3 +3932,10 @@ static const TypeInfo riscv_cpu_type_infos[] = {
 };
 
 DEFINE_TYPES(riscv_cpu_type_infos)
+
+static void riscv_accel_cpu_register_type(void)
+{
+    accel_cpu_register_type(CPU_RESOLVING_TYPE);
+}
+
+type_init(riscv_accel_cpu_register_type)
-- 
2.55.0.windows.3

[PATCH v5 2/3] Revert "target/riscv/kvm: restrict kvm-accel-riscv-cpu to riscv targets"

[Yonggang Luo]

This is redundant now as all accel-$cpu_type parent is already registered.

This reverts commit 2d3e6b4003d5380c245ce8ffac4b8866f6d10a33.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
---
 target/riscv/kvm/kvm-cpu.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 5beb602338..aa28098e10 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -27,7 +27,6 @@
 #include "qapi/qapi-builtin-type-infos.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
-#include "qemu/target-info.h"
 #include "qapi/visitor.h"
 #include "system/system.h"
 #include "system/kvm.h"
@@ -2241,7 +2240,6 @@ static const TypeInfo kvm_cpu_accel_type_info = {
 
     .parent = TYPE_ACCEL_CPU,
     .class_init = kvm_cpu_accel_class_init,
-    .is_available = target_base_riscv,
     .abstract = true,
 };
 static void kvm_cpu_accel_register_types(void)
-- 
2.55.0.windows.3

[PATCH v5 3/3] Revert "target/riscv/tcg: restrict tcg-accel-riscv-cpu to riscv targets"

[Yonggang Luo]

This is redundant now as all accel-$cpu_type parent is already registered.

This reverts commit ec65e16fd2ba012d57b1bbfcfcd04c31c4111924.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
---
 target/riscv/tcg/tcg-cpu.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index 5834ec1524..3d9c997329 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -1755,7 +1755,6 @@ static const TypeInfo riscv_tcg_cpu_accel_type_info = {
 
     .parent = TYPE_ACCEL_CPU,
     .class_init = riscv_tcg_cpu_accel_class_init,
-    .is_available = target_base_riscv,
     .abstract = true,
 };
 
-- 
2.55.0.windows.3

Re: [PATCH v5 1/3] accel: register CPU parent only for AccelCPU subclasses

[Pierrick Bouvier]

On 11/5/2026 6:39 PM, Yonggang Luo wrote:
> accel_cpu_register_type() creates the abstract parent
> accel-<cpu type>. A subclass names that parent, and
> type_initialize() aborts when the parent is missing. The old
> type_init registered only target_cpu_type(), which is one name
> in a multi-target process. Call the helper from the CPU type
> init of each target that has an AccelCPU subclass.
> 
> ARM calls it because whpx-common.c parents accel-arm-cpu on
> aarch64-softmmu. i386 calls it for TCG, KVM, HVF, NVMM, and
> MSHV. i386-softmmu and x86_64-softmmu each pass their own
> CPU_RESOLVING_TYPE, so WHPX on x86_64-softmmu finds
> accel-x86_64-cpu. RISC-V calls it for TCG and KVM. PowerPC
> calls it for KVM.
> 
> Other targets have no AccelCPU subclass. Machine init looks up
> tcg-accel-<cpu type> or kvm-accel-<cpu type> and skips a missing
> class, so those targets do not need the parent.
> 
> No extra tests is needed, as these QOM types already be
> tested by the existing logic instantiating all QOM types.
> 
> Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> ---
>  accel/accel-common.c      | 6 ++----
>  include/accel/accel-cpu.h | 2 ++
>  target/arm/cpu.c          | 2 ++
>  target/i386/cpu.c         | 2 ++
>  target/ppc/cpu_init.c     | 2 ++
>  target/riscv/cpu.c        | 8 ++++++++
>  6 files changed, 18 insertions(+), 4 deletions(-)
> 

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Tested-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>

Regards,
Pierrick

Re: [PATCH v5 0/3] Register accel-$cpu_type for all targets

[Pierrick Bouvier]

On 11/5/2026 6:39 PM, Yonggang Luo wrote:
> A multi-target system binary links more than one target.
> accel_cpu_register_type() creates the abstract parent accel-$cpu_type for each
> target that has an AccelCPU subclass. ARM, i386, RISC-V, and PowerPC call it.
> Other targets have no such subclass, and machine init skips a missing class.
> 
> test-multi-target already instantiates every QOM type, so this series adds no
> parent check.
> 
> This is an alternative to gating accelerator CPU types with is_available. The
> RISC-V TCG and KVM gates are reverted here as redundant.
> 
> v4: https://lore.kernel.org/qemu-devel/20261105183310.1614-1-luoyonggang@gmail.com/
> 
> Changes v4 -> v5:
> 
> - Drop test_accel_cpu_parent(). test_qom_types_are_unique() already instantiates
>   every QOM type
> 
> Yonggang Luo (3):
>   accel: register CPU parent only for AccelCPU subclasses
>   Revert "target/riscv/kvm: restrict kvm-accel-riscv-cpu to riscv
>     targets"
>   Revert "target/riscv/tcg: restrict tcg-accel-riscv-cpu to riscv
>     targets"
> 
>  accel/accel-common.c       | 6 ++----
>  include/accel/accel-cpu.h  | 2 ++
>  target/arm/cpu.c           | 2 ++
>  target/i386/cpu.c          | 2 ++
>  target/ppc/cpu_init.c      | 2 ++
>  target/riscv/cpu.c         | 8 ++++++++
>  target/riscv/kvm/kvm-cpu.c | 2 --
>  target/riscv/tcg/tcg-cpu.c | 1 -
>  8 files changed, 18 insertions(+), 7 deletions(-)
> 

Thanks Yonggang, I'll pull this as part of multi-target once the trunk
reopens.

Regards,
Pierrick

Re: [PATCH v5 1/3] accel: register CPU parent only for AccelCPU subclasses

[Yonggang Luo]

On Sat, Nov 7, 2026 at 1:59 AM Pierrick Bouvier
<pierrick.bouvier@oss.qualcomm.com> wrote:
>
> On 11/5/2026 6:39 PM, Yonggang Luo wrote:
> > accel_cpu_register_type() creates the abstract parent
> > accel-<cpu type>. A subclass names that parent, and
> > type_initialize() aborts when the parent is missing. The old
> > type_init registered only target_cpu_type(), which is one name
> > in a multi-target process. Call the helper from the CPU type
> > init of each target that has an AccelCPU subclass.
> >
> > ARM calls it because whpx-common.c parents accel-arm-cpu on
> > aarch64-softmmu. i386 calls it for TCG, KVM, HVF, NVMM, and
> > MSHV. i386-softmmu and x86_64-softmmu each pass their own
> > CPU_RESOLVING_TYPE, so WHPX on x86_64-softmmu finds
> > accel-x86_64-cpu. RISC-V calls it for TCG and KVM. PowerPC
> > calls it for KVM.
> >
> > Other targets have no AccelCPU subclass. Machine init looks up
> > tcg-accel-<cpu type> or kvm-accel-<cpu type> and skips a missing
> > class, so those targets do not need the parent.
> >
> > No extra tests is needed, as these QOM types already be
> > tested by the existing logic instantiating all QOM types.
> >
> > Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> > ---
> >  accel/accel-common.c      | 6 ++----
> >  include/accel/accel-cpu.h | 2 ++
> >  target/arm/cpu.c          | 2 ++
> >  target/i386/cpu.c         | 2 ++
> >  target/ppc/cpu_init.c     | 2 ++
> >  target/riscv/cpu.c        | 8 ++++++++
> >  6 files changed, 18 insertions(+), 4 deletions(-)
> >
>
> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> Tested-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>


Thanks for your good review, otherwise it won't be in such good shape.

>
> Regards,
> Pierrick



-- 
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo

Re: [PATCH v5 1/3] accel: register CPU parent only for AccelCPU subclasses

[Daniel P. Berrangé]

On Fri, Nov 06, 2026 at 10:39:33AM +0800, Yonggang Luo wrote:
> accel_cpu_register_type() creates the abstract parent
> accel-<cpu type>. A subclass names that parent, and
> type_initialize() aborts when the parent is missing. The old
> type_init registered only target_cpu_type(), which is one name
> in a multi-target process. Call the helper from the CPU type
> init of each target that has an AccelCPU subclass.
> 
> ARM calls it because whpx-common.c parents accel-arm-cpu on
> aarch64-softmmu. i386 calls it for TCG, KVM, HVF, NVMM, and
> MSHV. i386-softmmu and x86_64-softmmu each pass their own
> CPU_RESOLVING_TYPE, so WHPX on x86_64-softmmu finds
> accel-x86_64-cpu. RISC-V calls it for TCG and KVM. PowerPC
> calls it for KVM.
> 
> Other targets have no AccelCPU subclass. Machine init looks up
> tcg-accel-<cpu type> or kvm-accel-<cpu type> and skips a missing
> class, so those targets do not need the parent.
> 
> No extra tests is needed, as these QOM types already be
> tested by the existing logic instantiating all QOM types.
> 
> Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> ---
>  accel/accel-common.c      | 6 ++----
>  include/accel/accel-cpu.h | 2 ++
>  target/arm/cpu.c          | 2 ++
>  target/i386/cpu.c         | 2 ++
>  target/ppc/cpu_init.c     | 2 ++
>  target/riscv/cpu.c        | 8 ++++++++
>  6 files changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/accel/accel-common.c b/accel/accel-common.c
> index 00a400243f..441d1b77fa 100644
> --- a/accel/accel-common.c
> +++ b/accel/accel-common.c
> @@ -130,9 +130,9 @@ static const TypeInfo accel_types[] = {
>  
>  DEFINE_TYPES(accel_types)
>  
> -static void register_accel_target_type(void)
> +void accel_cpu_register_type(const char *cpu_type)
>  {
> -    g_autofree char *name = g_strconcat("accel-", target_cpu_type(), NULL);
> +    g_autofree char *name = g_strconcat("accel-", cpu_type, NULL);
>      const TypeInfo accel_cpu_type = {
>          .name = name,
>          .parent = TYPE_OBJECT,
> @@ -142,5 +142,3 @@ static void register_accel_target_type(void)
>  
>      type_register_static(&accel_cpu_type);
>  }

Is there a reason why we need to register this base class
repeatedly for each target ? This class is defined in target
independent code and the target specific behaviour is provided
by subclasses AFAICT, so I'm not seeing why we need to
duplicate the class per target.

I just proposed changing its name to "accel-cpu" so that
it is always available:

  https://lists.gnu.org/archive/html/qemu-devel/2026-11/msg02741.html

> diff --git a/include/accel/accel-cpu.h b/include/accel/accel-cpu.h
> index 9e7eede7c3..2fdb64d2ae 100644
> --- a/include/accel/accel-cpu.h
> +++ b/include/accel/accel-cpu.h
> @@ -20,4 +20,6 @@ typedef struct AccelCPUClass {
>      bool (*cpu_target_realize)(CPUState *cpu, Error **errp);
>  } AccelCPUClass;
>  
> +void accel_cpu_register_type(const char *cpu_type);
> +
>  #endif /* ACCEL_CPU_H */
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 71681447b2..725f1f3a5f 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -28,6 +28,7 @@
>  #include "qemu/module.h"
>  #include "qapi/error.h"
>  #include "cpu.h"
> +#include "accel/accel-cpu.h"
>  #ifdef CONFIG_TCG
>  #include "exec/translation-block.h"
>  #include "accel/tcg/cpu-ops.h"
> @@ -2753,6 +2754,7 @@ static const TypeInfo arm_cpu_type_info = {
>  
>  static void arm_cpu_register_types(void)
>  {
> +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
>      type_register_static(&arm_cpu_type_info);
>  }
>  
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index eab0d5a4d4..31b09e6f8e 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -23,6 +23,7 @@
>  #include "qemu/qemu-print.h"
>  #include "qemu/hw-version.h"
>  #include "cpu.h"
> +#include "accel/accel-cpu.h"
>  #include "tcg/helper-tcg.h"
>  #include "exec/translation-block.h"
>  #include "system/hvf.h"
> @@ -11093,6 +11094,7 @@ static void x86_cpu_register_types(void)
>  {
>      int i;
>  
> +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
>      type_register_static(&x86_cpu_type_info);
>      for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
>          x86_register_cpudef_types(&builtin_x86_defs[i]);
> diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> index 7f3036d903..fe3f2549b7 100644
> --- a/target/ppc/cpu_init.c
> +++ b/target/ppc/cpu_init.c
> @@ -43,6 +43,7 @@
>  #include "exec/page-protection.h"
>  #include "exec/watchpoint.h"
>  #include "helper_regs.h"
> +#include "accel/accel-cpu.h"
>  #include "internal.h"
>  #include "spr_common.h"
>  #include "power8-pmu.h"
> @@ -7589,6 +7590,7 @@ static const TypeInfo ppc_vhyp_type_info = {
>  
>  static void ppc_cpu_register_types(void)
>  {
> +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
>      type_register_static(&ppc_cpu_type_info);
>  #ifndef CONFIG_USER_ONLY
>      type_register_static(&ppc_vhyp_type_info);
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 362e561809..10e24f20e8 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -25,6 +25,7 @@
>  #include "qemu/guest-random.h"
>  #include "qemu/atomic.h"
>  #include "cpu.h"
> +#include "accel/accel-cpu.h"
>  #include "cpu_vendorid.h"
>  #include "target/riscv/tcg/csr.h"
>  #include "internals.h"
> @@ -3931,3 +3932,10 @@ static const TypeInfo riscv_cpu_type_infos[] = {
>  };
>  
>  DEFINE_TYPES(riscv_cpu_type_infos)
> +
> +static void riscv_accel_cpu_register_type(void)
> +{
> +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
> +}
> +
> +type_init(riscv_accel_cpu_register_type)
> -- 
> 2.55.0.windows.3
> 
> 

With regards,
Daniel
-- 
|: https://berrange.com       ~~        https://hachyderm.io/@berrange :|
|: https://libvirt.org          ~~          https://entangle-photo.org :|
|: https://pixelfed.art/berrange   ~~    https://fstop138.berrange.com :|

Re: [PATCH v5 1/3] accel: register CPU parent only for AccelCPU subclasses

[Yonggang Luo]

On Thu, Nov 12, 2026 at 9:43 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Fri, Nov 06, 2026 at 10:39:33AM +0800, Yonggang Luo wrote:
> > accel_cpu_register_type() creates the abstract parent
> > accel-<cpu type>. A subclass names that parent, and
> > type_initialize() aborts when the parent is missing. The old
> > type_init registered only target_cpu_type(), which is one name
> > in a multi-target process. Call the helper from the CPU type
> > init of each target that has an AccelCPU subclass.
> >
> > ARM calls it because whpx-common.c parents accel-arm-cpu on
> > aarch64-softmmu. i386 calls it for TCG, KVM, HVF, NVMM, and
> > MSHV. i386-softmmu and x86_64-softmmu each pass their own
> > CPU_RESOLVING_TYPE, so WHPX on x86_64-softmmu finds
> > accel-x86_64-cpu. RISC-V calls it for TCG and KVM. PowerPC
> > calls it for KVM.
> >
> > Other targets have no AccelCPU subclass. Machine init looks up
> > tcg-accel-<cpu type> or kvm-accel-<cpu type> and skips a missing
> > class, so those targets do not need the parent.
> >
> > No extra tests is needed, as these QOM types already be
> > tested by the existing logic instantiating all QOM types.
> >
> > Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> > ---
> >  accel/accel-common.c      | 6 ++----
> >  include/accel/accel-cpu.h | 2 ++
> >  target/arm/cpu.c          | 2 ++
> >  target/i386/cpu.c         | 2 ++
> >  target/ppc/cpu_init.c     | 2 ++
> >  target/riscv/cpu.c        | 8 ++++++++
> >  6 files changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/accel/accel-common.c b/accel/accel-common.c
> > index 00a400243f..441d1b77fa 100644
> > --- a/accel/accel-common.c
> > +++ b/accel/accel-common.c
> > @@ -130,9 +130,9 @@ static const TypeInfo accel_types[] = {
> >
> >  DEFINE_TYPES(accel_types)
> >
> > -static void register_accel_target_type(void)
> > +void accel_cpu_register_type(const char *cpu_type)
> >  {
> > -    g_autofree char *name = g_strconcat("accel-", target_cpu_type(), NULL);
> > +    g_autofree char *name = g_strconcat("accel-", cpu_type, NULL);
> >      const TypeInfo accel_cpu_type = {
> >          .name = name,
> >          .parent = TYPE_OBJECT,
> > @@ -142,5 +142,3 @@ static void register_accel_target_type(void)
> >
> >      type_register_static(&accel_cpu_type);
> >  }
>
> Is there a reason why we need to register this base class
> repeatedly for each target ? This class is defined in target
> independent code and the target specific behaviour is provided
> by subclasses AFAICT, so I'm not seeing why we need to
> duplicate the class per target.
>
> I just proposed changing its name to "accel-cpu" so that
> it is always available:


Yeap, this is my first choice:

https://lore.kernel.org/qemu-devel/20260823150731.896-2-luoyonggang@gmail.com/#r

If there is no strong objection, I like this.

>
>   https://lists.gnu.org/archive/html/qemu-devel/2026-11/msg02741.html
>
> > diff --git a/include/accel/accel-cpu.h b/include/accel/accel-cpu.h
> > index 9e7eede7c3..2fdb64d2ae 100644
> > --- a/include/accel/accel-cpu.h
> > +++ b/include/accel/accel-cpu.h
> > @@ -20,4 +20,6 @@ typedef struct AccelCPUClass {
> >      bool (*cpu_target_realize)(CPUState *cpu, Error **errp);
> >  } AccelCPUClass;
> >
> > +void accel_cpu_register_type(const char *cpu_type);
> > +
> >  #endif /* ACCEL_CPU_H */
> > diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> > index 71681447b2..725f1f3a5f 100644
> > --- a/target/arm/cpu.c
> > +++ b/target/arm/cpu.c
> > @@ -28,6 +28,7 @@
> >  #include "qemu/module.h"
> >  #include "qapi/error.h"
> >  #include "cpu.h"
> > +#include "accel/accel-cpu.h"
> >  #ifdef CONFIG_TCG
> >  #include "exec/translation-block.h"
> >  #include "accel/tcg/cpu-ops.h"
> > @@ -2753,6 +2754,7 @@ static const TypeInfo arm_cpu_type_info = {
> >
> >  static void arm_cpu_register_types(void)
> >  {
> > +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
> >      type_register_static(&arm_cpu_type_info);
> >  }
> >
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index eab0d5a4d4..31b09e6f8e 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -23,6 +23,7 @@
> >  #include "qemu/qemu-print.h"
> >  #include "qemu/hw-version.h"
> >  #include "cpu.h"
> > +#include "accel/accel-cpu.h"
> >  #include "tcg/helper-tcg.h"
> >  #include "exec/translation-block.h"
> >  #include "system/hvf.h"
> > @@ -11093,6 +11094,7 @@ static void x86_cpu_register_types(void)
> >  {
> >      int i;
> >
> > +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
> >      type_register_static(&x86_cpu_type_info);
> >      for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
> >          x86_register_cpudef_types(&builtin_x86_defs[i]);
> > diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> > index 7f3036d903..fe3f2549b7 100644
> > --- a/target/ppc/cpu_init.c
> > +++ b/target/ppc/cpu_init.c
> > @@ -43,6 +43,7 @@
> >  #include "exec/page-protection.h"
> >  #include "exec/watchpoint.h"
> >  #include "helper_regs.h"
> > +#include "accel/accel-cpu.h"
> >  #include "internal.h"
> >  #include "spr_common.h"
> >  #include "power8-pmu.h"
> > @@ -7589,6 +7590,7 @@ static const TypeInfo ppc_vhyp_type_info = {
> >
> >  static void ppc_cpu_register_types(void)
> >  {
> > +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
> >      type_register_static(&ppc_cpu_type_info);
> >  #ifndef CONFIG_USER_ONLY
> >      type_register_static(&ppc_vhyp_type_info);
> > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> > index 362e561809..10e24f20e8 100644
> > --- a/target/riscv/cpu.c
> > +++ b/target/riscv/cpu.c
> > @@ -25,6 +25,7 @@
> >  #include "qemu/guest-random.h"
> >  #include "qemu/atomic.h"
> >  #include "cpu.h"
> > +#include "accel/accel-cpu.h"
> >  #include "cpu_vendorid.h"
> >  #include "target/riscv/tcg/csr.h"
> >  #include "internals.h"
> > @@ -3931,3 +3932,10 @@ static const TypeInfo riscv_cpu_type_infos[] = {
> >  };
> >
> >  DEFINE_TYPES(riscv_cpu_type_infos)
> > +
> > +static void riscv_accel_cpu_register_type(void)
> > +{
> > +    accel_cpu_register_type(CPU_RESOLVING_TYPE);
> > +}
> > +
> > +type_init(riscv_accel_cpu_register_type)
> > --
> > 2.55.0.windows.3
> >
> >
>
> With regards,
> Daniel
> --
> |: https://berrange.com       ~~        https://hachyderm.io/@berrange :|
> |: https://libvirt.org          ~~          https://entangle-photo.org :|
> |: https://pixelfed.art/berrange   ~~    https://fstop138.berrange.com :|
>


--
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo