Re: [PATCH v7 08/52] i386/tdx: Initialize TDX before creating TD vcpus

[Francesco Lavra <francescolavra.fl@gmail.com>]

On Fri, 2025-01-24 at 08:20 -0500, Xiaoyao Li wrote:
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 45867dbe0839..e35a9fbd687e 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -540,8 +540,15 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
>  
>      trace_kvm_init_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
>  
> +    /*
> +     * tdx_pre_create_vcpu() may call cpu_x86_cpuid(). It in turn
> may call
> +     * kvm_vm_ioctl(). Set cpu->kvm_state in advance to avoid NULL
> pointer
> +     * dereference.
> +     */
> +    cpu->kvm_state = s;

This assignment should be removed from kvm_create_vcpu(), as now it's
redundant there.

>      ret = kvm_arch_pre_create_vcpu(cpu, errp);
>      if (ret < 0) {
> +        cpu->kvm_state = NULL;

No need to reset cpu->kvm_state to NULL, there already are other error
conditions under which cpu->kvm_state remains initialized.

>          goto err;
>      }
>  
> @@ -550,6 +557,7 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
>          error_setg_errno(errp, -ret,
>                           "kvm_init_vcpu: kvm_create_vcpu failed
> (%lu)",
>                           kvm_arch_vcpu_id(cpu));
> +        cpu->kvm_state = NULL;

Same here.