FROMLIST: firmware/smccc: Call arch-specific hook on discovering KVM services

arm64 will soon require its own callback to initialise services
that are only availably on this architecture. Introduce a hook
that can be overloaded by the architecture.

Link: https://lore.kernel.org/r/20211004174849.2831548-12-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Bug: 209580772
Change-Id: I743e1786df1477b3c9fab0fe2e5ea52a7dcdf01f
Signed-off-by: Will Deacon <willdeacon@google.com>

arch/arm/include/asm/hypervisor.h

@@ -6,5 +6,6 @@
 
 void kvm_init_hyp_services(void);
 bool kvm_arm_hyp_service_available(u32 func_id);
+void kvm_arm_init_hyp_services(void);
 
 #endif

arch/arm64/include/asm/hypervisor.h

@@ -6,5 +6,6 @@
 
 void kvm_init_hyp_services(void);
 bool kvm_arm_hyp_service_available(u32 func_id);
+void kvm_arm_init_hyp_services(void);
 
 #endif

drivers/firmware/smccc/kvm_guest.c

@@ -9,6 +9,8 @@
 
 #include <asm/hypervisor.h>
 
+void __weak kvm_arm_init_hyp_services(void) {}
+
 static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { };
 
 void __init kvm_init_hyp_services(void)
@@ -38,6 +40,8 @@ void __init kvm_init_hyp_services(void)
 
 	pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n",
 		 res.a3, res.a2, res.a1, res.a0);
+
+	kvm_arm_init_hyp_services();
 }
 
 bool kvm_arm_hyp_service_available(u32 func_id)