builtin-run: Pass console= parameter based on active console

x86 already does this in the backend, but doing it in the generic code
means that it is possible to boot a defconfig arm64 kernel under kvmtool
without having to specify any additional parameters at all.
Signed-off-by: Will Deacon <will.deacon@arm.com>

builtin-run.c

@@ -454,6 +454,7 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
 	static char real_cmdline[2048], default_name[20];
 	unsigned int nr_online_cpus;
 	struct kvm *kvm = kvm__new();
+	bool video;
 
 	if (IS_ERR(kvm))
 		return kvm;
@@ -536,6 +537,8 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
 	if (!kvm->cfg.console)
 		kvm->cfg.console = DEFAULT_CONSOLE;
 
+	video = kvm->cfg.vnc || kvm->cfg.sdl || kvm->cfg.gtk;
+
 	if (!strncmp(kvm->cfg.console, "virtio", 6))
 		kvm->cfg.active_console  = CONSOLE_VIRTIO;
 	else if (!strncmp(kvm->cfg.console, "serial", 6))
@@ -564,7 +567,22 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
                 kvm->cfg.network = DEFAULT_NETWORK;
 
 	memset(real_cmdline, 0, sizeof(real_cmdline));
-	kvm__arch_set_cmdline(real_cmdline, kvm->cfg.vnc || kvm->cfg.sdl || kvm->cfg.gtk);
+	kvm__arch_set_cmdline(real_cmdline, video);
+
+	if (video) {
+		strcat(real_cmdline, "console=tty0");
+	} else {
+		switch (kvm->cfg.active_console) {
+		case CONSOLE_HV:
+			/* Fallthrough */
+		case CONSOLE_VIRTIO:
+			strcat(real_cmdline, "console=hvc0");
+			break;
+		case CONSOLE_8250:
+			strcat(real_cmdline, "console=ttyS0");
+			break;
+		}
+	}
 
 	if (!kvm->cfg.guest_name) {
 		if (kvm->cfg.custom_rootfs) {

x86/kvm.c

@@ -124,9 +124,9 @@ void kvm__arch_set_cmdline(char *cmdline, bool video)
 	strcpy(cmdline, "noapic noacpi pci=conf1 reboot=k panic=1 i8042.direct=1 "
 				"i8042.dumbkbd=1 i8042.nopnp=1");
 	if (video)
-		strcat(cmdline, " video=vesafb console=tty0");
+		strcat(cmdline, " video=vesafb");
 	else
-		strcat(cmdline, " console=ttyS0 earlyprintk=serial i8042.noaux=1");
+		strcat(cmdline, " earlyprintk=serial i8042.noaux=1");
 }
 
 /* Architecture-specific KVM init */