Re: [PATCH v2 5/7] x86/hvm: Use __initdata_cf_clobber for hvm_funcs

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.02.2022 13:56, Andrew Cooper wrote:
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -88,7 +88,7 @@ unsigned int opt_hvm_debug_level __read_mostly;
>  integer_param("hvm_debug", opt_hvm_debug_level);
>  #endif
>  
> -struct hvm_function_table hvm_funcs __read_mostly;
> +struct hvm_function_table __ro_after_init hvm_funcs;

Strictly speaking this is an unrelated change. I'm fine with it living here,
but half a sentence would be nice in the description.

> --- a/xen/arch/x86/hvm/svm/svm.c
> +++ b/xen/arch/x86/hvm/svm/svm.c
> @@ -2513,7 +2513,7 @@ static void cf_check svm_set_reg(struct vcpu *v, 
> unsigned int reg, uint64_t val)
>      }
>  }
>  
> -static struct hvm_function_table __initdata svm_function_table = {
> +static struct hvm_function_table __initdata_cf_clobber svm_function_table = {
>      .name                 = "SVM",
>      .cpu_up_prepare       = svm_cpu_up_prepare,
>      .cpu_dead             = svm_cpu_dead,
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index 41db538a9e3d..758df3321884 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -2473,7 +2473,7 @@ static void cf_check vmx_set_reg(struct vcpu *v, 
> unsigned int reg, uint64_t val)
>      vmx_vmcs_exit(v);
>  }
>  
> -static struct hvm_function_table __initdata vmx_function_table = {
> +static struct hvm_function_table __initdata_cf_clobber vmx_function_table = {
>      .name                 = "VMX",
>      .cpu_up_prepare       = vmx_cpu_up_prepare,
>      .cpu_dead             = vmx_cpu_dead,

While I'd like to re-raise my concern regarding the non-pointer fields
in these structure instances (just consider a sequence of enough bool
bitfields, which effectively can express any value, including ones
which would appear like pointers into .text), since for now all is okay
afaict:
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan