Adds another qemu platform.

qemu_virt: One core, deterministic.
qemu_virt4: Four core, non-deterministic.

common/inc/plat/config.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#if defined(PLATFORM_qemu_virt)
+#if defined(PLATFORM_qemu_virt) || defined(PLATFORM_qemu_virt4)
 #include "plat/qemu_virt.h"
 #elif defined(PLATFORM_sifive_unleashed)
 #include "plat/sifive_unleashed.h"

common/plat/qemu_virt.mk

@@ -2,7 +2,8 @@ export ARCH=rv64imac_zicsr
 export ABI=lp64
 export CMODEL=medany
 export QEMU_MACHINE=virt
-export QEMU_SMP=4
+export QEMU_SMP=1
+export QEMU_OPTIONS=-icount 3
 export COMMON_INC:=${ROOT}/common/inc
 export COMMON_LIB:=${ROOT}/common/build/${PLATFORM}
 export STARTFILES:=${ROOT}/common/build/${PLATFORM}/start

common/plat/qemu_virt4.mk

@@ -0,0 +1,9 @@
+export ARCH=rv64imac_zicsr
+export ABI=lp64
+export CMODEL=medany
+export QEMU_MACHINE=virt
+export QEMU_SMP=4
+export COMMON_INC:=${ROOT}/common/inc
+export COMMON_LIB:=${ROOT}/common/build/${PLATFORM}
+export STARTFILES:=${ROOT}/common/build/${PLATFORM}/start
+PLAT_SRCS=src/drivers/uart/ns16550a.c src/drivers/time.c

projects/ping-pong/app0/main.c

@@ -89,7 +89,7 @@ int main(void)
 	s3k_msg_t msg;
 	s3k_reply_t reply;
 	memcpy(msg.data, "pong", 5);
-	s3k_reg_write(S3K_REG_SERVTIME, 4500);
+	s3k_reg_write(S3K_REG_SERVTIME, 100);
 	while (1) {
 		do {
 			reply = s3k_sock_sendrecv(11, &msg);

scripts/qemu.sh

@@ -15,4 +15,4 @@ if [[ -z "$QEMU_SMP" ]]; then
 fi
 
 qemu-system-riscv64 -M $QEMU_MACHINE -smp $QEMU_SMP -m 128M -nographic -bios none \
-	$LOADER $@
+	$LOADER $QEMU_OPTIONS $@