Re: [RFC PATCH v3 05/19] target/arm/kvm: enable writable implementation ID registers

Hi Khushit,

On 7/16/26 11:38 PM, Khushit Shah wrote:
> Enable KVM_CAP_ARM_WRITABLE_IMP_ID_REGS if the host kernel supports it.
> This allows QEMU to write implementation-defined ID registers (MIDR,
> REVIDR) so that named CPU models can present the correct values to the
> guest instead of inheriting the host's identity.
This is a subset of 
[RFC PATCH RESEND 0/4] hw/arm/virt: Add support for Target
Implementation CPUs
https://lore.kernel.org/all/[email protected]/

and especially 1/4

Thanks

Eric
>
> Signed-off-by: Khushit Shah <[email protected]>
> ---
>  target/arm/kvm.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 76583db3f0..63b3727e05 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -741,6 +741,13 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>          }
>      }
>  
> +    if (kvm_check_extension(s, KVM_CAP_ARM_WRITABLE_IMP_ID_REGS)) {
> +        if (kvm_vm_enable_cap(s, KVM_CAP_ARM_WRITABLE_IMP_ID_REGS, 0)) {
> +            error_report("Failed to enable "
> +                         "KVM_CAP_ARM_WRITABLE_IMP_ID_REGS cap");
> +        }
> +    }
> +
>      if (s->kvm_eager_split_size) {
>          uint32_t sizes;
>