Re: [PATCH] x86/hvm: print valid CR4 bits in case of error

[Jan Beulich <jbeulich@xxxxxxxx>]

On 07.06.2023 15:46, Roger Pau Monne wrote:
> --- a/xen/arch/x86/hvm/domain.c
> +++ b/xen/arch/x86/hvm/domain.c
> @@ -266,8 +266,8 @@ int arch_set_info_hvm_guest(struct vcpu *v, const 
> vcpu_hvm_context_t *ctx)
>  
>      if ( v->arch.hvm.guest_cr[4] & ~hvm_cr4_guest_valid_bits(d) )
>      {
> -        gprintk(XENLOG_ERR, "Bad CR4 value: %#016lx\n",
> -                v->arch.hvm.guest_cr[4]);
> +        gprintk(XENLOG_ERR, "Bad CR4 value: %#016lx (valid: %016lx)\n",
> +                v->arch.hvm.guest_cr[4], hvm_cr4_guest_valid_bits(d));
>          return -EINVAL;
>      }
>  
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -1018,8 +1018,8 @@ static int cf_check hvm_load_cpu_ctxt(struct domain *d, 
> hvm_domain_context_t *h)
>  
>      if ( ctxt.cr4 & ~hvm_cr4_guest_valid_bits(d) )
>      {
> -        printk(XENLOG_G_ERR "HVM%d restore: bad CR4 %#" PRIx64 "\n",
> -               d->domain_id, ctxt.cr4);
> +        printk(XENLOG_G_ERR "HVM%d restore: bad CR4 %#016lx (valid: 
> %016lx)\n",

I'm not convinced printing a lot of leading zeros is really useful here.
However, if you switch to that model, then all uses of the # modifier
need to go away (in the earlier instance it would be nice if you also
fixed the pre-existing issue then).

Jan