Re: [PATCH v5 1/6] sev/i386: Add initial support for SEV-ES

[Dr. David Alan Gilbert]

* Tom Lendacky (thomas.lendacky@amd.com) wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> Provide initial support for SEV-ES. This includes creating a function to
> indicate the guest is an SEV-ES guest (which will return false until all
> support is in place), performing the proper SEV initialization and
> ensuring that the guest CPU state is measured as part of the launch.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Co-developed-by: Jiri Slaby <jslaby@suse.cz>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  target/i386/cpu.c      |  1 +
>  target/i386/sev-stub.c |  6 ++++++
>  target/i386/sev.c      | 44 ++++++++++++++++++++++++++++++++++++++++--
>  target/i386/sev_i386.h |  1 +
>  4 files changed, 50 insertions(+), 2 deletions(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 35459a38bb..9adb34c091 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -5986,6 +5986,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> uint32_t count,
>          break;
>      case 0x8000001F:
>          *eax = sev_enabled() ? 0x2 : 0;
> +        *eax |= sev_es_enabled() ? 0x8 : 0;

Yep, matches your docs - it would be great if these magic constants
could become enums or #defines somewhere.

anyway,


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

>          *ebx = sev_get_cbit_position();
>          *ebx |= sev_get_reduced_phys_bits() << 6;
>          *ecx = 0;
> diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c
> index c1fecc2101..229a2ee77b 100644
> --- a/target/i386/sev-stub.c
> +++ b/target/i386/sev-stub.c
> @@ -49,8 +49,14 @@ SevCapability *sev_get_capabilities(Error **errp)
>      error_setg(errp, "SEV is not available in this QEMU");
>      return NULL;
>  }
> +
>  int sev_inject_launch_secret(const char *hdr, const char *secret,
>                               uint64_t gpa, Error **errp)
>  {
>      return 1;
>  }
> +
> +bool sev_es_enabled(void)
> +{
> +    return false;
> +}
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 1546606811..fce2128c07 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -360,6 +360,12 @@ sev_enabled(void)
>      return !!sev_guest;
>  }
>  
> +bool
> +sev_es_enabled(void)
> +{
> +    return false;
> +}
> +
>  uint64_t
>  sev_get_me_mask(void)
>  {
> @@ -580,6 +586,20 @@ sev_launch_update_data(SevGuestState *sev, uint8_t 
> *addr, uint64_t len)
>      return ret;
>  }
>  
> +static int
> +sev_launch_update_vmsa(SevGuestState *sev)
> +{
> +    int ret, fw_error;
> +
> +    ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_UPDATE_VMSA, NULL, 
> &fw_error);
> +    if (ret) {
> +        error_report("%s: LAUNCH_UPDATE_VMSA ret=%d fw_error=%d '%s'",
> +                __func__, ret, fw_error, fw_error_to_str(fw_error));
> +    }
> +
> +    return ret;
> +}
> +
>  static void
>  sev_launch_get_measure(Notifier *notifier, void *unused)
>  {
> @@ -592,6 +612,14 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>          return;
>      }
>  
> +    if (sev_es_enabled()) {
> +        /* measure all the VM save areas before getting launch_measure */
> +        ret = sev_launch_update_vmsa(sev);
> +        if (ret) {
> +            exit(1);
> +        }
> +    }
> +
>      measurement = g_new0(struct kvm_sev_launch_measure, 1);
>  
>      /* query the measurement blob length */
> @@ -686,7 +714,7 @@ sev_guest_init(const char *id)
>  {
>      SevGuestState *sev;
>      char *devname;
> -    int ret, fw_error;
> +    int ret, fw_error, cmd;
>      uint32_t ebx;
>      uint32_t host_cbitpos;
>      struct sev_user_data_status status = {};
> @@ -747,8 +775,20 @@ sev_guest_init(const char *id)
>      sev->api_major = status.api_major;
>      sev->api_minor = status.api_minor;
>  
> +    if (sev_es_enabled()) {
> +        if (!(status.flags & SEV_STATUS_FLAGS_CONFIG_ES)) {
> +            error_report("%s: guest policy requires SEV-ES, but "
> +                         "host SEV-ES support unavailable",
> +                         __func__);
> +            goto err;
> +        }
> +        cmd = KVM_SEV_ES_INIT;
> +    } else {
> +        cmd = KVM_SEV_INIT;
> +    }
> +
>      trace_kvm_sev_init();
> -    ret = sev_ioctl(sev->sev_fd, KVM_SEV_INIT, NULL, &fw_error);
> +    ret = sev_ioctl(sev->sev_fd, cmd, NULL, &fw_error);
>      if (ret) {
>          error_report("%s: failed to initialize ret=%d fw_error=%d '%s'",
>                       __func__, ret, fw_error, fw_error_to_str(fw_error));
> diff --git a/target/i386/sev_i386.h b/target/i386/sev_i386.h
> index 4db6960f60..4f9a5e9b21 100644
> --- a/target/i386/sev_i386.h
> +++ b/target/i386/sev_i386.h
> @@ -29,6 +29,7 @@
>  #define SEV_POLICY_SEV          0x20
>  
>  extern bool sev_enabled(void);
> +extern bool sev_es_enabled(void);
>  extern uint64_t sev_get_me_mask(void);
>  extern SevInfo *sev_get_info(void);
>  extern uint32_t sev_get_cbit_position(void);
> -- 
> 2.30.0
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK