Re: [RFC PATCH 2/4] i386/sev: Switch to use confidential_guest_kvm_init()

[Daniel P . Berrangé]

On Tue, Feb 06, 2024 at 03:28:50AM -0500, Xiaoyao Li wrote:
> Use confidential_guest_kvm_init() instead of calling SEV specific
> sev_kvm_init(). As a bouns, it fits to future TDX when TDX implements
> its own confidential_guest_support and .kvm_init().
> 
> Move the "TypeInfo sev_guest_info" definition and related functions to
> the end of the file, to avoid declaring the sev_kvm_init() ahead.
> 
> Clean up the sve-stub.c since it's not needed anymore.
> 
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
>  target/i386/kvm/kvm.c       |   2 +-
>  target/i386/kvm/meson.build |   2 -
>  target/i386/kvm/sev-stub.c  |   5 --
>  target/i386/sev.c           | 120 +++++++++++++++++++-----------------
>  target/i386/sev.h           |   2 -
>  5 files changed, 63 insertions(+), 68 deletions(-)
> 
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 76a66246eb72..bb63bba61fa1 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -2534,7 +2534,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>       * mechanisms are supported in future (e.g. TDX), they'll need
>       * their own initialization either here or elsewhere.
>       */
> -    ret = sev_kvm_init(ms->cgs, &local_err);
> +    ret = confidential_guest_kvm_init(ms->cgs, &local_err);

If you agree with my comment in patch 1 about the API expecting non-NULL,
then this would need to be conditionalized (same for the 2 following
patches too)

   if (ms->cgs) {
      ret = confidential_guest_kvm_init(....)
      if (ret < 0) {
         ....
      }
   }

>      if (ret < 0) {
>          error_report_err(local_err);
>          return ret;
> diff --git a/target/i386/kvm/meson.build b/target/i386/kvm/meson.build
> index 84d9143e6029..e7850981e62d 100644
> --- a/target/i386/kvm/meson.build
> +++ b/target/i386/kvm/meson.build
> @@ -7,8 +7,6 @@ i386_kvm_ss.add(files(
>  
>  i386_kvm_ss.add(when: 'CONFIG_XEN_EMU', if_true: files('xen-emu.c'))
>  
> -i386_kvm_ss.add(when: 'CONFIG_SEV', if_false: files('sev-stub.c'))
> -
>  i386_system_ss.add(when: 'CONFIG_HYPERV', if_true: files('hyperv.c'), 
> if_false: files('hyperv-stub.c'))
>  
>  i386_system_ss.add_all(when: 'CONFIG_KVM', if_true: i386_kvm_ss)
> diff --git a/target/i386/kvm/sev-stub.c b/target/i386/kvm/sev-stub.c
> index 1be5341e8a6a..4a1560cf8ad7 100644
> --- a/target/i386/kvm/sev-stub.c
> +++ b/target/i386/kvm/sev-stub.c
> @@ -14,8 +14,3 @@
>  #include "qemu/osdep.h"
>  #include "sev.h"
>  
> -int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
> -{
> -    /* If we get here, cgs must be some non-SEV thing */
> -    return 0;
> -}

You can actually delete this entire file, since you removed the
only method in it, and stopped building it in the meson.build
patch above.

> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 173de91afe7d..19e79d3631d0 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -353,63 +353,6 @@ static void sev_guest_set_kernel_hashes(Object *obj, 
> bool value, Error **errp)
>      sev->kernel_hashes = value;
>  }
>  
> -static void
> -sev_guest_class_init(ObjectClass *oc, void *data)
> -{
> -    object_class_property_add_str(oc, "sev-device",
> -                                  sev_guest_get_sev_device,
> -                                  sev_guest_set_sev_device);
> -    object_class_property_set_description(oc, "sev-device",
> -            "SEV device to use");
> -    object_class_property_add_str(oc, "dh-cert-file",
> -                                  sev_guest_get_dh_cert_file,
> -                                  sev_guest_set_dh_cert_file);
> -    object_class_property_set_description(oc, "dh-cert-file",
> -            "guest owners DH certificate (encoded with base64)");
> -    object_class_property_add_str(oc, "session-file",
> -                                  sev_guest_get_session_file,
> -                                  sev_guest_set_session_file);
> -    object_class_property_set_description(oc, "session-file",
> -            "guest owners session parameters (encoded with base64)");
> -    object_class_property_add_bool(oc, "kernel-hashes",
> -                                   sev_guest_get_kernel_hashes,
> -                                   sev_guest_set_kernel_hashes);
> -    object_class_property_set_description(oc, "kernel-hashes",
> -            "add kernel hashes to guest firmware for measured Linux boot");
> -}
> -
> -static void
> -sev_guest_instance_init(Object *obj)
> -{
> -    SevGuestState *sev = SEV_GUEST(obj);
> -
> -    sev->sev_device = g_strdup(DEFAULT_SEV_DEVICE);
> -    sev->policy = DEFAULT_GUEST_POLICY;
> -    object_property_add_uint32_ptr(obj, "policy", &sev->policy,
> -                                   OBJ_PROP_FLAG_READWRITE);
> -    object_property_add_uint32_ptr(obj, "handle", &sev->handle,
> -                                   OBJ_PROP_FLAG_READWRITE);
> -    object_property_add_uint32_ptr(obj, "cbitpos", &sev->cbitpos,
> -                                   OBJ_PROP_FLAG_READWRITE);
> -    object_property_add_uint32_ptr(obj, "reduced-phys-bits",
> -                                   &sev->reduced_phys_bits,
> -                                   OBJ_PROP_FLAG_READWRITE);
> -}
> -
> -/* sev guest info */
> -static const TypeInfo sev_guest_info = {
> -    .parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> -    .name = TYPE_SEV_GUEST,
> -    .instance_size = sizeof(SevGuestState),
> -    .instance_finalize = sev_guest_finalize,
> -    .class_init = sev_guest_class_init,
> -    .instance_init = sev_guest_instance_init,
> -    .interfaces = (InterfaceInfo[]) {
> -        { TYPE_USER_CREATABLE },
> -        { }
> -    }
> -};
> -
>  bool
>  sev_enabled(void)
>  {
> @@ -906,7 +849,7 @@ sev_vm_state_change(void *opaque, bool running, RunState 
> state)
>      }
>  }
>  
> -int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
> +static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
>  {
>      SevGuestState *sev
>          = (SevGuestState *)object_dynamic_cast(OBJECT(cgs), TYPE_SEV_GUEST);
> @@ -1383,6 +1326,67 @@ bool 
> sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp)
>      return ret;
>  }
>  
> +static void
> +sev_guest_class_init(ObjectClass *oc, void *data)
> +{
> +    ConfidentialGuestSupportClass *klass = 
> CONFIDENTIAL_GUEST_SUPPORT_CLASS(oc);
> +
> +    klass->kvm_init = sev_kvm_init;
> +
> +    object_class_property_add_str(oc, "sev-device",
> +                                  sev_guest_get_sev_device,
> +                                  sev_guest_set_sev_device);
> +    object_class_property_set_description(oc, "sev-device",
> +            "SEV device to use");
> +    object_class_property_add_str(oc, "dh-cert-file",
> +                                  sev_guest_get_dh_cert_file,
> +                                  sev_guest_set_dh_cert_file);
> +    object_class_property_set_description(oc, "dh-cert-file",
> +            "guest owners DH certificate (encoded with base64)");
> +    object_class_property_add_str(oc, "session-file",
> +                                  sev_guest_get_session_file,
> +                                  sev_guest_set_session_file);
> +    object_class_property_set_description(oc, "session-file",
> +            "guest owners session parameters (encoded with base64)");
> +    object_class_property_add_bool(oc, "kernel-hashes",
> +                                   sev_guest_get_kernel_hashes,
> +                                   sev_guest_set_kernel_hashes);
> +    object_class_property_set_description(oc, "kernel-hashes",
> +            "add kernel hashes to guest firmware for measured Linux boot");
> +}
> +
> +static void
> +sev_guest_instance_init(Object *obj)
> +{
> +    SevGuestState *sev = SEV_GUEST(obj);
> +
> +    sev->sev_device = g_strdup(DEFAULT_SEV_DEVICE);
> +    sev->policy = DEFAULT_GUEST_POLICY;
> +    object_property_add_uint32_ptr(obj, "policy", &sev->policy,
> +                                   OBJ_PROP_FLAG_READWRITE);
> +    object_property_add_uint32_ptr(obj, "handle", &sev->handle,
> +                                   OBJ_PROP_FLAG_READWRITE);
> +    object_property_add_uint32_ptr(obj, "cbitpos", &sev->cbitpos,
> +                                   OBJ_PROP_FLAG_READWRITE);
> +    object_property_add_uint32_ptr(obj, "reduced-phys-bits",
> +                                   &sev->reduced_phys_bits,
> +                                   OBJ_PROP_FLAG_READWRITE);
> +}
> +
> +/* sev guest info */
> +static const TypeInfo sev_guest_info = {
> +    .parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> +    .name = TYPE_SEV_GUEST,
> +    .instance_size = sizeof(SevGuestState),
> +    .instance_finalize = sev_guest_finalize,
> +    .class_init = sev_guest_class_init,
> +    .instance_init = sev_guest_instance_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_USER_CREATABLE },
> +        { }
> +    }
> +};
> +
>  static void
>  sev_register_types(void)
>  {
> diff --git a/target/i386/sev.h b/target/i386/sev.h
> index e7499c95b1e8..9e10d09539a7 100644
> --- a/target/i386/sev.h
> +++ b/target/i386/sev.h
> @@ -57,6 +57,4 @@ int sev_inject_launch_secret(const char *hdr, const char 
> *secret,
>  int sev_es_save_reset_vector(void *flash_ptr, uint64_t flash_size);
>  void sev_es_set_reset_vector(CPUState *cpu);
>  
> -int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp);
> -
>  #endif
> -- 
> 2.34.1
> 

With regards,
Daniel
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