Re: [PATCH v2 03/13] s390x: protvirt: Support unpack facility

[David Hildenbrand <david@redhat.com>]

On 29.11.19 10:47, Janosch Frank wrote:
> When a guest has saved a ipib of type 5 and call diagnose308 with
> subcode 10, we have to setup the protected processing environment via
> Ultravisor calls. The calls are done by KVM and are exposed via an API.
> 
> The following steps are necessary:
> 1. Create a VM (register it with the Ultravisor)
> 2. Create secure CPUs for all of our current cpus

I do wonder why KVM can't handle that when switching to the encrypted
VM. Any specific reason QEMU has to be involved?

I would have guessed s390_pv_vm_create() can handle that internally. KVM
knows all the VCPUs.

[...]
>      switch (reset_type) {
>      case S390_RESET_EXTERNAL:
>      case S390_RESET_REIPL:
> @@ -357,6 +361,28 @@ static void s390_machine_reset(MachineState *machine)
>          run_on_cpu(cs, s390_do_cpu_initial_reset, RUN_ON_CPU_NULL);
>          run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
>          break;
> +    case S390_RESET_PV: /* Subcode 10 */
> +        subsystem_reset();
> +        s390_crypto_reset();
> +
> +        CPU_FOREACH(t) {
> +            run_on_cpu(t, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
> +        }
> +
> +        /* Create SE VM */
> +        s390_pv_vm_create();
> +        CPU_FOREACH(t) {
> +            s390_pv_vcpu_create(t);
> +        }

So, on any other reboot, the VM/CPUs won't get cleaned up?

(is this really a "create" or rather a "s390_pv_vm_enable()").

The "create" terminology somehow sounds wrong to me ...

> +
> +        /* Set SE header and unpack */
> +        s390_ipl_prepare_pv_header();
> +        /* Decrypt image */
> +        s390_ipl_pv_unpack();
> +        /* Verify integrity */
> +        s390_pv_verify();
> +        s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
> +        break;
>      default:
>          g_assert_not_reached();
>      }
> diff --git a/target/s390x/cpu_features_def.inc.h b/target/s390x/cpu_features_def.inc.h
> index 31dff0d84e..60db28351d 100644
> --- a/target/s390x/cpu_features_def.inc.h
> +++ b/target/s390x/cpu_features_def.inc.h
> @@ -107,6 +107,7 @@ DEF_FEAT(DEFLATE_BASE, "deflate-base", STFL, 151, "Deflate-conversion facility (
>  DEF_FEAT(VECTOR_PACKED_DECIMAL_ENH, "vxpdeh", STFL, 152, "Vector-Packed-Decimal-Enhancement Facility")
>  DEF_FEAT(MSA_EXT_9, "msa9-base", STFL, 155, "Message-security-assist-extension-9 facility (excluding subfunctions)")
>  DEF_FEAT(ETOKEN, "etoken", STFL, 156, "Etoken facility")
> +DEF_FEAT(UNPACK, "unpack", STFL, 161, "Unpack facility")
>  
>  /* Features exposed via SCLP SCCB Byte 80 - 98  (bit numbers relative to byte-80) */
>  DEF_FEAT(SIE_GSLS, "gsls", SCLP_CONF_CHAR, 40, "SIE: Guest-storage-limit-suppression facility")
> 


-- 
Thanks,

David / dhildenb