firmware: smccc: Support both smc and hvc conduits for getting hyp UUID

When Linux is running as the root partition under Microsoft Hypervisor
(MSHV) a.k.a Hyper-V, smc is used as the conduit for smc calls.

Extend arm_smccc_hypervisor_has_uuid() to support this usecase. Use
arm_smccc_1_1_invoke to retrieve and use the appropriate conduit instead
of supporting only hvc.

Boot tested on MSHV guest, MSHV root & KVM guest.

Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
Message-Id: <20250521094049.960056-1-anirudh@anirudhrb.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
index cd65b434dc6e8b81ecdf98bc64e3dc67baeb8666..bdee057db2fd3bd01060cab821b1ed0ebce59e69 100644 (file)
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c
@@ -72,10 +72,7 @@ bool arm_smccc_hypervisor_has_uuid(const uuid_t *hyp_uuid)
        struct arm_smccc_res res = {};
        uuid_t uuid;
 
-       if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC)
-               return false;
-
-       arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+       arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
        if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
                return false;