platform: generic-arm64: Guard vsock-rust

Only add vsock-rust dependency if we're building Trusty for a regular or
protected VM (-virt builds) where ARM64_BOOT_PROTOCOL is set to X0_DTB.

Bug: None
Test: Presubmit
Change-Id: I5bbb7e79528d211cd3e850c03914050cf38db313

platform/generic-arm64/platform.c

diff --git a/platform/generic-arm64/platform.c b/platform/generic-arm64/platform.c
index bff837a..16568a3 100644
--- a/platform/generic-arm64/platform.c
+++ b/platform/generic-arm64/platform.c
@@ -31,7 +31,9 @@
 #include <platform/gic.h>
 #include <string.h>
 #include <sys/types.h>
+#if ARM64_BOOT_PROTOCOL_X0_DTB
 #include <vsock/vsock.h>
+#endif
 
 #include "debug.h"
 
@@ -156,6 +158,7 @@
 
 #endif
 
+#if ARM64_BOOT_PROTOCOL_X0_DTB
 int static pci_init_fdt(const void* fdt) {
     int fdt_pci_offset =
             fdt_node_offset_by_compatible(fdt, 0, "pci-host-cam-generic");
@@ -174,6 +177,7 @@
 
     return pci_init_mmio(pci_paddr, pci_size, 1 << 11);
 }
+#endif /* ARM64_BOOT_PROTOCOL_X0_DTB */
 
 static void platform_after_vm_init(uint level) {
 #ifdef GIC_VERSION

platform/generic-arm64/rules.mk

diff --git a/platform/generic-arm64/rules.mk b/platform/generic-arm64/rules.mk
index 6c25bd8..a58b0f6 100644
--- a/platform/generic-arm64/rules.mk
+++ b/platform/generic-arm64/rules.mk
@@ -68,8 +68,14 @@
 
 MODULE_DEPS += \
 	dev/timer/arm_generic \
+
+# vsock-rust only supports aarch64 (and x86_64)
+ifeq (X0_DTB,$(ARM64_BOOT_PROTOCOL))
+MODULE_DEPS += \
 	dev/virtio/vsock-rust \
 
+endif
+
 GLOBAL_DEFINES += \
 	MEMBASE=$(MEMBASE) \
 	MEMSIZE=$(MEMSIZE) \