Re: [PATCH] target/i386: SEV: do not assume machine->cgs is SEV

[Zhao Liu]

On Thu, Jun 06, 2024 at 12:44:09AM +0200, Paolo Bonzini wrote:
> Date: Thu,  6 Jun 2024 00:44:09 +0200
> From: Paolo Bonzini <pbonzini@redhat.com>
> Subject: [PATCH] target/i386: SEV: do not assume machine->cgs is SEV
> X-Mailer: git-send-email 2.45.1
> 
> There can be other confidential computing classes that are not derived
> from sev-common.  Avoid aborting when encountering them.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  target/i386/sev.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 004c667ac14..97e15f8b7a9 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -1710,7 +1710,9 @@ void sev_es_set_reset_vector(CPUState *cpu)
>  {
>      X86CPU *x86;
>      CPUX86State *env;
> -    SevCommonState *sev_common = 
> SEV_COMMON(MACHINE(qdev_get_machine())->cgs);
> +    ConfidentialGuestSupport *cgs = MACHINE(qdev_get_machine())->cgs;
> +    SevCommonState *sev_common = SEV_COMMON(
> +        object_dynamic_cast(OBJECT(cgs), TYPE_SEV_COMMON));

SEV_COMMON(object_dynamic_cast()) looks to be twice cast, we can just
force to do conversion with pointer type:

(SevCommonState *) object_dynamic_cast(OBJECT(cgs), TYPE_SEV_COMMON)

>      /* Only update if we have valid reset information */
>      if (!sev_common || !sev_common->reset_data_valid) {
> -- 
> 2.45.1
> 
>