On Wed, Mar 20, 2024 at 03:39:27AM -0500, Michael Roth wrote:
> Most of the current 'query-sev' command is relevant to both legacy
> SEV/SEV-ES guests and SEV-SNP guests, with 2 exceptions:
>
> - 'policy' is a 64-bit field for SEV-SNP, not 32-bit, and
> the meaning of the bit positions has changed
> - 'handle' is not relevant to SEV-SNP
>
> To address this, this patch adds a new 'sev-type' field that can be
> used as a discriminator to select between SEV and SEV-SNP-specific
> fields/formats without breaking compatibility for existing management
> tools (so long as management tools that add support for launching
> SEV-SNP guest update their handling of query-sev appropriately).
>
> The corresponding HMP command has also been fixed up similarly.
>
> Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
> ---
> qapi/misc-target.json | 71 ++++++++++++++++++++++++++++++++++---------
> target/i386/sev.c | 50 ++++++++++++++++++++----------
> target/i386/sev.h | 3 ++
> 3 files changed, 94 insertions(+), 30 deletions(-)
>
> diff --git a/qapi/misc-target.json b/qapi/misc-target.json
> index 4e0a6492a9..daceb85d95 100644
> --- a/qapi/misc-target.json
> +++ b/qapi/misc-target.json
> @@ -47,6 +47,49 @@
> 'send-update', 'receive-update' ],
> 'if': 'TARGET_I386' }
>
> +##
> +# @SevGuestType:
> +#
> +# An enumeration indicating the type of SEV guest being run.
> +#
> +# @sev: The guest is a legacy SEV or SEV-ES guest.
> +# @sev-snp: The guest is an SEV-SNP guest.
> +#
> +# Since: 6.2
Now 9.1 at the earliest.
> +##
> +{ 'enum': 'SevGuestType',
> + 'data': [ 'sev', 'sev-snp' ],
> + 'if': 'TARGET_I386' }
> +
> +##
> +# @SevGuestInfo:
> +#
> +# Information specific to legacy SEV/SEV-ES guests.
> +#
> +# @policy: SEV policy value
> +#
> +# @handle: SEV firmware handle
> +#
> +# Since: 2.12
> +##
> +{ 'struct': 'SevGuestInfo',
> + 'data': { 'policy': 'uint32',
> + 'handle': 'uint32' },
> + 'if': 'TARGET_I386' }
> +
> +##
> +# @SevSnpGuestInfo:
> +#
> +# Information specific to SEV-SNP guests.
> +#
> +# @snp-policy: SEV-SNP policy value
> +#
> +# Since: 6.2
> +##
> +{ 'struct': 'SevSnpGuestInfo',
> + 'data': { 'snp-policy': 'uint64' },
> + 'if': 'TARGET_I386' }
IMHO it can just be called 'policy' still, since
it is implicitly within a 'Snp' specific type.
> +
> ##
> # @SevInfo:
> #
> @@ -60,25 +103,25 @@
> #
> # @build-id: SEV FW build id
> #
> -# @policy: SEV policy value
> -#
> # @state: SEV guest state
> #
> -# @handle: SEV firmware handle
> +# @sev-type: Type of SEV guest being run
> #
> # Since: 2.12
> ##
> -{ 'struct': 'SevInfo',
> - 'data': { 'enabled': 'bool',
> - 'api-major': 'uint8',
> - 'api-minor' : 'uint8',
> - 'build-id' : 'uint8',
> - 'policy' : 'uint32',
> - 'state' : 'SevState',
> - 'handle' : 'uint32'
> - },
> - 'if': 'TARGET_I386'
> -}
> +{ 'union': 'SevInfo',
> + 'base': { 'enabled': 'bool',
> + 'api-major': 'uint8',
> + 'api-minor' : 'uint8',
> + 'build-id' : 'uint8',
> + 'state' : 'SevState',
> + 'sev-type' : 'SevGuestType' },
> + 'discriminator': 'sev-type',
> + 'data': {
> + 'sev': 'SevGuestInfo',
> + 'sev-snp': 'SevSnpGuestInfo' },
> + 'if': 'TARGET_I386' }
> +
>
> ##
> # @query-sev:
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 43e6c0172f..b03d70a3d1 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -353,25 +353,27 @@ static SevInfo *sev_get_info(void)
> {
> SevInfo *info;
> SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs);
> - SevGuestState *sev_guest =
> - (SevGuestState *)object_dynamic_cast(OBJECT(sev_common),
> - TYPE_SEV_GUEST);
>
> info = g_new0(SevInfo, 1);
> info->enabled = sev_enabled();
>
> if (info->enabled) {
> - if (sev_guest) {
> - info->handle = sev_guest->handle;
> - }
> info->api_major = sev_common->api_major;
> info->api_minor = sev_common->api_minor;
> info->build_id = sev_common->build_id;
> info->state = sev_common->state;
> - /* we only report the lower 32-bits of policy for SNP, ok for now... */
> - info->policy =
> - (uint32_t)object_property_get_uint(OBJECT(sev_common),
> - "policy", NULL);
> +
> + if (sev_snp_enabled()) {
> + info->sev_type = SEV_GUEST_TYPE_SEV_SNP;
> + info->u.sev_snp.snp_policy =
> + object_property_get_uint(OBJECT(sev_common), "policy", NULL);
> + } else {
> + info->sev_type = SEV_GUEST_TYPE_SEV;
> + info->u.sev.handle = SEV_GUEST(sev_common)->handle;
> + info->u.sev.policy =
> + (uint32_t)object_property_get_uint(OBJECT(sev_common),
> + "policy", NULL);
> + }
> }
Ok, this is fixing the issues I reported earlier.
For 'policy' I do wonder if we really need to push it into the
type specific part of the union, as oppposed to having a common
'policy' field that is uint64 in size.
As mentioned earlier, on the wire there's no distinction between
int32/int64s, so there's no compat issues with changing it from
int32 to int64.
>
> return info;
> @@ -394,20 +396,36 @@ void hmp_info_sev(Monitor *mon, const QDict *qdict)
> {
> SevInfo *info = sev_get_info();
>
> - if (info && info->enabled) {
> - monitor_printf(mon, "handle: %d\n", info->handle);
> + if (!info || !info->enabled) {
> + monitor_printf(mon, "SEV is not enabled\n");
> + goto out;
> + }
> +
> + if (sev_snp_enabled()) {
> monitor_printf(mon, "state: %s\n", SevState_str(info->state));
> monitor_printf(mon, "build: %d\n", info->build_id);
> monitor_printf(mon, "api version: %d.%d\n",
> info->api_major, info->api_minor);
> monitor_printf(mon, "debug: %s\n",
> - info->policy & SEV_POLICY_NODBG ? "off" : "on");
> - monitor_printf(mon, "key-sharing: %s\n",
> - info->policy & SEV_POLICY_NOKS ? "off" : "on");
> + info->u.sev_snp.snp_policy & SEV_SNP_POLICY_DBG ? "on"
> + : "off");
> + monitor_printf(mon, "SMT allowed: %s\n",
> + info->u.sev_snp.snp_policy & SEV_SNP_POLICY_SMT ? "on"
> + : "off");
> } else {
> - monitor_printf(mon, "SEV is not enabled\n");
> + monitor_printf(mon, "handle: %d\n", info->u.sev.handle);
> + monitor_printf(mon, "state: %s\n", SevState_str(info->state));
> + monitor_printf(mon, "build: %d\n", info->build_id);
> + monitor_printf(mon, "api version: %d.%d\n",
> + info->api_major, info->api_minor);
This set of three fields is identical in both branches, so the duplication
in printing it should be eliminated.
> + monitor_printf(mon, "debug: %s\n",
> + info->u.sev.policy & SEV_POLICY_NODBG ? "off" : "on");
> + monitor_printf(mon, "key-sharing: %s\n",
> + info->u.sev.policy & SEV_POLICY_NOKS ? "off" : "on");
> }
> + monitor_printf(mon, "SEV type: %s\n", SevGuestType_str(info->sev_type));
I'd say 'SEV type' should be printed before everything else, since
that value is the discriminator for interpreting the other data that
is printed.
>
> +out:
> qapi_free_SevInfo(info);
> }
With regards,
Daniel
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