diff mbox series

[4/4] m68k: add Virtual M68k Machine

Message ID 20201013155124.451774-5-laurent@vivier.eu (mailing list archive)
State New, archived
Headers show
Series m68k: add Virtual M68k Machine | expand

Commit Message

Laurent Vivier Oct. 13, 2020, 3:51 p.m. UTC
The machine is based on Goldfish interfaces defined by Google
for Android simulator. It uses Goldfish-rtc (timer and RTC),
Goldfish-pic (PIC) and Goldfish-tty (for serial port and early tty).

The machine is created with 128 virtio-mmio bus, and they can
be used to use serial console, GPU, disk, NIC, HID, ...

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 default-configs/devices/m68k-softmmu.mak      |   1 +
 .../standard-headers/asm-m68k/bootinfo-virt.h |  17 +
 hw/m68k/virt.c                                | 296 ++++++++++++++++++
 MAINTAINERS                                   |   9 +
 hw/m68k/Kconfig                               |   8 +
 hw/m68k/meson.build                           |   1 +
 6 files changed, 332 insertions(+)
 create mode 100644 include/standard-headers/asm-m68k/bootinfo-virt.h
 create mode 100644 hw/m68k/virt.c

Comments

Laurent Vivier Oct. 13, 2020, 7:01 p.m. UTC | #1
Le 13/10/2020 à 19:56, Philippe Mathieu-Daudé a écrit :
> On 10/13/20 5:51 PM, Laurent Vivier wrote:
>> The machine is based on Goldfish interfaces defined by Google
>> for Android simulator. It uses Goldfish-rtc (timer and RTC),
>> Goldfish-pic (PIC) and Goldfish-tty (for serial port and early tty).
>>
>> The machine is created with 128 virtio-mmio bus, and they can
>> be used to use serial console, GPU, disk, NIC, HID, ...
>>
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>> ---
>>   default-configs/devices/m68k-softmmu.mak      |   1 +
>>   .../standard-headers/asm-m68k/bootinfo-virt.h |  17 +
>>   hw/m68k/virt.c                                | 296 ++++++++++++++++++
>>   MAINTAINERS                                   |   9 +
>>   hw/m68k/Kconfig                               |   8 +
>>   hw/m68k/meson.build                           |   1 +
>>   6 files changed, 332 insertions(+)
>>   create mode 100644 include/standard-headers/asm-m68k/bootinfo-virt.h
>>   create mode 100644 hw/m68k/virt.c
...
>> +/*
>> + * The GLUE (General Logic Unit) is an Apple custom integrated
>> circuit chip
>> + * that performs a variety of functions (RAM management, clock
>> generation, ...).
>> + * The GLUE chip receives interrupt requests from various devices,
>> + * assign priority to each, and asserts one or more interrupt line to
>> the
>> + * CPU.
> 
> Does your virt machine really requires a GLUE? Or only another
> cascaded PIC?

I agree code needs cleanup here.

We need something to set the ÌRQ level (priority) and vector (see
m68k_set_irq_level()).

>> + */
>> +
>> +typedef struct {
>> +    M68kCPU *cpu;
>> +    uint8_t ipr;
>> +} GLUEState;
>> +
>> +static void GLUE_set_irq(void *opaque, int irq, int level)
>> +{
>> +    GLUEState *s = opaque;
>> +    int i;
>> +
>> +    if (level) {
>> +        s->ipr |= 1 << irq;
>> +    } else {
>> +        s->ipr &= ~(1 << irq);
>> +    }
>> +
>> +    for (i = 7; i >= 0; i--) {
>> +        if ((s->ipr >> i) & 1) {
>> +            m68k_set_irq_level(s->cpu, i + 1, i + 25);
>> +            return;
>> +        }
>> +    }
>> +    m68k_set_irq_level(s->cpu, 0, 0);
>> +}
>> +
>> +static void main_cpu_reset(void *opaque)
>> +{
>> +    M68kCPU *cpu = opaque;
>> +    CPUState *cs = CPU(cpu);
>> +
>> +    cpu_reset(cs);
>> +    cpu->env.aregs[7] = ldl_phys(cs->as, 0);
>> +    cpu->env.pc = ldl_phys(cs->as, 4);
>> +}
>> +
>> +static void virt_init(MachineState *machine)
>> +{
>> +    M68kCPU *cpu = NULL;
>> +    int32_t kernel_size;
>> +    uint64_t elf_entry;
>> +    ram_addr_t initrd_base;
>> +    int32_t initrd_size;
>> +    ram_addr_t ram_size = machine->ram_size;
>> +    const char *kernel_filename = machine->kernel_filename;
>> +    const char *initrd_filename = machine->initrd_filename;
>> +    const char *kernel_cmdline = machine->kernel_cmdline;
>> +    hwaddr parameters_base;
>> +    DeviceState *dev;
>> +    DeviceState *pic_dev[7];
>> +    GLUEState *irq;
>> +    qemu_irq *cpu_pic;
>> +    SysBusDevice *sysbus;
>> +    hwaddr io_base;
>> +    int i;
>> +
>> +
>> +    if (ram_size > 3399672 * KiB) {
>> +        /*
>> +         * The physical memory can be up to 4 GiB - 16 MiB, but linux
>> +         * kernel crashes after this limit (~ 3.2 GiB)
>> +         */
>> +        error_report("Too much memory for this machine: %" PRId64 "
>> KiB, "
>> +                     "maximum 3399672 KiB", ram_size / KiB);
>> +        exit(1);
>> +    }
>> +
>> +    /* init CPUs */
>> +    cpu = M68K_CPU(cpu_create(machine->cpu_type));
> 
> Due to BOOTINFO1(..., BI_CPUTYPE, CPU_68040) below, don't you
> need to check machine->cpu_type == M68K_CPU_TYPE_NAME("m68040")?

Yes, you're right.

68030MMU is not implemented. So we can't use other CPU than 68040.

> 
>> +    qemu_register_reset(main_cpu_reset, cpu);
>> +
>> +    /* RAM */
>> +    memory_region_add_subregion(get_system_memory(), 0, machine->ram);
>> +
>> +    /* IRQ Glue */
>> +
>> +    irq = g_new0(GLUEState, 1);
>> +    irq->cpu = cpu;
>> +    cpu_pic = qemu_allocate_irqs(GLUE_set_irq, irq, 8);
>> +
>> +    /*
>> +     * 6 goldfish-pic
>> +     *
>> +     * map: 0xff000000 - 0xff006fff = 28 KiB
>> +     * IRQ: #1 (lower priority) -> #6 (higher priority)
>> +     *
>> +     */
>> +    io_base = VIRT_GF_PIC_MMIO_BASE;
>> +    for (i = 0; i < 6; i++) {
>> +        pic_dev[i] = qdev_new(TYPE_GOLDFISH_PIC);
>> +        sysbus = SYS_BUS_DEVICE(pic_dev[i]);
>> +        sysbus_realize_and_unref(sysbus, &error_fatal);
>> +
>> +        sysbus_mmio_map(sysbus, 0, io_base);
>> +        sysbus_connect_irq(sysbus, 0, cpu_pic[i]);
>> +
>> +        io_base += 0x1000;
>> +    }
>> +
>> +    /* goldfish-rtc */
>> +    dev = qdev_new(TYPE_GOLDFISH_RTC);
>> +    sysbus = SYS_BUS_DEVICE(dev);
>> +    sysbus_realize_and_unref(sysbus, &error_fatal);
>> +    sysbus_mmio_map(sysbus, 0, VIRT_GF_RTC_MMIO_BASE);
>> +    sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_GF_RTC_IRQ_BASE));
>> +
>> +    /* goldfish-tty */
>> +    dev = qdev_new(TYPE_GOLDFISH_TTY);
>> +    sysbus = SYS_BUS_DEVICE(dev);
>> +    qdev_prop_set_chr(dev, "chardev", serial_hd(0));
>> +    sysbus_realize_and_unref(sysbus, &error_fatal);
>> +    sysbus_mmio_map(sysbus, 0, VIRT_GF_TTY_MMIO_BASE);
>> +    sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_GF_TTY_IRQ_BASE));
>> +
>> +    /* virtio-mmio */
>> +    io_base = VIRT_VIRTIO_MMIO_BASE;
>> +    for (i = 0; i < 128; i++) {
>> +        dev = qdev_new(TYPE_VIRTIO_MMIO);
>> +        qdev_prop_set_bit(dev, "force-legacy", false);
>> +        sysbus = SYS_BUS_DEVICE(dev);
>> +        sysbus_realize_and_unref(sysbus, &error_fatal);
>> +        sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_VIRTIO_IRQ_BASE +
>> i));
>> +        sysbus_mmio_map(sysbus, 0, io_base);
>> +        io_base += 0x200;
>> +    }
>> +
>> +    if (kernel_filename) {
>> +        CPUState *cs = CPU(cpu);
>> +        uint64_t high;
>> +
>> +        kernel_size = load_elf(kernel_filename, NULL, NULL, NULL,
>> +                               &elf_entry, NULL, &high, NULL, 1,
>> +                               EM_68K, 0, 0);
>> +        if (kernel_size < 0) {
>> +            error_report("could not load kernel '%s'", kernel_filename);
>> +            exit(1);
>> +        }
>> +        stl_phys(cs->as, 4, elf_entry); /* reset initial PC */
>> +        parameters_base = (high + 1) & ~1;
>> +
>> +        BOOTINFO1(cs->as, parameters_base, BI_MACHTYPE, MACH_VIRT);
>> +        BOOTINFO1(cs->as, parameters_base, BI_FPUTYPE, FPU_68040);
>> +        BOOTINFO1(cs->as, parameters_base, BI_MMUTYPE, MMU_68040);
>> +        BOOTINFO1(cs->as, parameters_base, BI_CPUTYPE, CPU_68040);
> 
> (see machine->cpu_type question earlier).

see answer above.

>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index d0962a22e1b4..b08cf4251246 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1101,6 +1101,15 @@ F: include/hw/nubus/*
>>   F: include/hw/display/macfb.h
>>   F: include/hw/block/swim.h
>>   +virt
> 
> Maybe "m68k virt".

We have "virt" only for ARM, RISCV, Xtensa, ...
the m68k is implied by the qemu-system-m68k

> 
>> +M: Laurent Vivier <laurent@vivier.eu>
>> +S: Maintained
>> +F: hw/m68k/virt.c
>> +F: hw/char/goldfish_tty.c
>> +F: hw/intc/goldfish_pic.c
>> +F: include/hw/char/goldfish_tty.h
>> +F: include/hw/intc/goldfish_pic.h
>> +

Thanks,
Laurent
diff mbox series

Patch

diff --git a/default-configs/devices/m68k-softmmu.mak b/default-configs/devices/m68k-softmmu.mak
index 6629fd2aa330..7f8619e42786 100644
--- a/default-configs/devices/m68k-softmmu.mak
+++ b/default-configs/devices/m68k-softmmu.mak
@@ -8,3 +8,4 @@  CONFIG_AN5206=y
 CONFIG_MCF5208=y
 CONFIG_NEXTCUBE=y
 CONFIG_Q800=y
+CONFIG_M68K_VIRT=y
diff --git a/include/standard-headers/asm-m68k/bootinfo-virt.h b/include/standard-headers/asm-m68k/bootinfo-virt.h
new file mode 100644
index 000000000000..b3d90a601513
--- /dev/null
+++ b/include/standard-headers/asm-m68k/bootinfo-virt.h
@@ -0,0 +1,17 @@ 
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+** asm/bootinfo-virt.h -- Virtual-m68k-specific boot information definitions
+*/
+
+#ifndef _UAPI_ASM_M68K_BOOTINFO_VIRT_H
+#define _UAPI_ASM_M68K_BOOTINFO_VIRT_H
+
+#define BI_VIRT_QEMU_VERSION	0x8000
+#define BI_VIRT_GF_PIC_BASE	0x8001
+#define BI_VIRT_GF_RTC_BASE	0x8002
+#define BI_VIRT_GF_TTY_BASE	0x8003
+#define BI_VIRT_VIRTIO_BASE	0x8004
+
+#define VIRT_BOOTI_VERSION	MK_BI_VERSION(2, 0)
+
+#endif /* _UAPI_ASM_M68K_BOOTINFO_MAC_H */
diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c
new file mode 100644
index 000000000000..8b89373dafdb
--- /dev/null
+++ b/hw/m68k/virt.c
@@ -0,0 +1,296 @@ 
+/*
+ * SPDX-License-Identifer: GPL-2.0-or-later
+ *
+ * QEMU Vitual M68K Machine
+ *
+ * (c) 2020 Laurent Vivier <laurent@vivier.eu>
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "qemu-common.h"
+#include "sysemu/sysemu.h"
+#include "cpu.h"
+#include "hw/hw.h"
+#include "hw/boards.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "elf.h"
+#include "hw/loader.h"
+#include "ui/console.h"
+#include "exec/address-spaces.h"
+#include "hw/sysbus.h"
+#include "standard-headers/asm-m68k/bootinfo.h"
+#include "standard-headers/asm-m68k/bootinfo-virt.h"
+#include "bootinfo.h"
+#include "net/net.h"
+#include "qapi/error.h"
+#include "sysemu/qtest.h"
+#include "sysemu/runstate.h"
+#include "sysemu/reset.h"
+
+#include "hw/char/goldfish_tty.h"
+#include "hw/rtc/goldfish_rtc.h"
+#include "hw/intc/goldfish_pic.h"
+#include "hw/virtio/virtio-mmio.h"
+#include "hw/virtio/virtio-blk.h"
+
+/*
+ * 6 goldfish-pic for CPU IRQ #1 to IRQ #6
+ * CPU IRQ #1 -> PIC #1
+ *               IRQ #1 to IRQ #31 -> unused
+ *               IRQ #32 -> goldfish-tty
+ * CPU IRQ #2 -> PIC #2
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 1 to 32
+ * CPU IRQ #3 -> PIC #3
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 33 to 64
+ * CPU IRQ #4 -> PIC #4
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 65 to 96
+ * CPU IRQ #5 -> PIC #5
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 97 to 128
+ * CPU IRQ #6 -> PIC #5
+ *               IRQ #1 -> goldfish-rtc
+ *               IRQ #2 to IRQ #32 -> unused
+ * CPU IRQ #7 -> NMI
+ */
+
+#define PIC_IRQ_BASE(num)     (8 + (num - 1) * 32)
+#define PIC_IRQ(num, irq)     (PIC_IRQ_BASE(num) + irq - 1)
+#define PIC_GPIO(pic_irq)     (qdev_get_gpio_in(pic_dev[(pic_irq - 8) / 32], \
+                                                (pic_irq - 8) % 32))
+
+#define VIRT_GF_PIC_MMIO_BASE 0xff000000     /* MMIO: 0xff000000 - 0xff005fff */
+#define VIRT_GF_PIC_IRQ_BASE  1              /* IRQ: #1 -> #6 */
+
+/* 1 goldfish-rtc (and timer) */
+#define VIRT_GF_RTC_MMIO_BASE 0xff006000     /* MMIO: 0xff006000 - 0xff006fff */
+#define VIRT_GF_RTC_IRQ_BASE  PIC_IRQ(6, 1)  /* PIC: #6, IRQ: #1 */
+
+/* 1 goldfish-tty */
+#define VIRT_GF_TTY_MMIO_BASE 0xff007000     /* MMIO: 0xff007000 - 0xff007000 */
+#define VIRT_GF_TTY_IRQ_BASE  PIC_IRQ(1, 32) /* PIC: #1, IRQ: #32 */
+/*
+ * virtio-mmio size is 0x200 bytes
+ * we use 4 goldfish-pic to attach them,
+ * we can attach 32 virtio devices / goldfish-pic
+ * -> we can manage 32 * 4 = 128 virtio devices
+ */
+#define VIRT_VIRTIO_MMIO_BASE 0xff010000     /* MMIO: 0xff010000 - 0xff01ffff */
+#define VIRT_VIRTIO_IRQ_BASE  PIC_IRQ(2, 1)  /* PIC: 2, 3, 4, 5, IRQ: ALL */
+
+/*
+ * The GLUE (General Logic Unit) is an Apple custom integrated circuit chip
+ * that performs a variety of functions (RAM management, clock generation, ...).
+ * The GLUE chip receives interrupt requests from various devices,
+ * assign priority to each, and asserts one or more interrupt line to the
+ * CPU.
+ */
+
+typedef struct {
+    M68kCPU *cpu;
+    uint8_t ipr;
+} GLUEState;
+
+static void GLUE_set_irq(void *opaque, int irq, int level)
+{
+    GLUEState *s = opaque;
+    int i;
+
+    if (level) {
+        s->ipr |= 1 << irq;
+    } else {
+        s->ipr &= ~(1 << irq);
+    }
+
+    for (i = 7; i >= 0; i--) {
+        if ((s->ipr >> i) & 1) {
+            m68k_set_irq_level(s->cpu, i + 1, i + 25);
+            return;
+        }
+    }
+    m68k_set_irq_level(s->cpu, 0, 0);
+}
+
+static void main_cpu_reset(void *opaque)
+{
+    M68kCPU *cpu = opaque;
+    CPUState *cs = CPU(cpu);
+
+    cpu_reset(cs);
+    cpu->env.aregs[7] = ldl_phys(cs->as, 0);
+    cpu->env.pc = ldl_phys(cs->as, 4);
+}
+
+static void virt_init(MachineState *machine)
+{
+    M68kCPU *cpu = NULL;
+    int32_t kernel_size;
+    uint64_t elf_entry;
+    ram_addr_t initrd_base;
+    int32_t initrd_size;
+    ram_addr_t ram_size = machine->ram_size;
+    const char *kernel_filename = machine->kernel_filename;
+    const char *initrd_filename = machine->initrd_filename;
+    const char *kernel_cmdline = machine->kernel_cmdline;
+    hwaddr parameters_base;
+    DeviceState *dev;
+    DeviceState *pic_dev[7];
+    GLUEState *irq;
+    qemu_irq *cpu_pic;
+    SysBusDevice *sysbus;
+    hwaddr io_base;
+    int i;
+
+
+    if (ram_size > 3399672 * KiB) {
+        /*
+         * The physical memory can be up to 4 GiB - 16 MiB, but linux
+         * kernel crashes after this limit (~ 3.2 GiB)
+         */
+        error_report("Too much memory for this machine: %" PRId64 " KiB, "
+                     "maximum 3399672 KiB", ram_size / KiB);
+        exit(1);
+    }
+
+    /* init CPUs */
+    cpu = M68K_CPU(cpu_create(machine->cpu_type));
+    qemu_register_reset(main_cpu_reset, cpu);
+
+    /* RAM */
+    memory_region_add_subregion(get_system_memory(), 0, machine->ram);
+
+    /* IRQ Glue */
+
+    irq = g_new0(GLUEState, 1);
+    irq->cpu = cpu;
+    cpu_pic = qemu_allocate_irqs(GLUE_set_irq, irq, 8);
+
+    /*
+     * 6 goldfish-pic
+     *
+     * map: 0xff000000 - 0xff006fff = 28 KiB
+     * IRQ: #1 (lower priority) -> #6 (higher priority)
+     *
+     */
+    io_base = VIRT_GF_PIC_MMIO_BASE;
+    for (i = 0; i < 6; i++) {
+        pic_dev[i] = qdev_new(TYPE_GOLDFISH_PIC);
+        sysbus = SYS_BUS_DEVICE(pic_dev[i]);
+        sysbus_realize_and_unref(sysbus, &error_fatal);
+
+        sysbus_mmio_map(sysbus, 0, io_base);
+        sysbus_connect_irq(sysbus, 0, cpu_pic[i]);
+
+        io_base += 0x1000;
+    }
+
+    /* goldfish-rtc */
+    dev = qdev_new(TYPE_GOLDFISH_RTC);
+    sysbus = SYS_BUS_DEVICE(dev);
+    sysbus_realize_and_unref(sysbus, &error_fatal);
+    sysbus_mmio_map(sysbus, 0, VIRT_GF_RTC_MMIO_BASE);
+    sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_GF_RTC_IRQ_BASE));
+
+    /* goldfish-tty */
+    dev = qdev_new(TYPE_GOLDFISH_TTY);
+    sysbus = SYS_BUS_DEVICE(dev);
+    qdev_prop_set_chr(dev, "chardev", serial_hd(0));
+    sysbus_realize_and_unref(sysbus, &error_fatal);
+    sysbus_mmio_map(sysbus, 0, VIRT_GF_TTY_MMIO_BASE);
+    sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_GF_TTY_IRQ_BASE));
+
+    /* virtio-mmio */
+    io_base = VIRT_VIRTIO_MMIO_BASE;
+    for (i = 0; i < 128; i++) {
+        dev = qdev_new(TYPE_VIRTIO_MMIO);
+        qdev_prop_set_bit(dev, "force-legacy", false);
+        sysbus = SYS_BUS_DEVICE(dev);
+        sysbus_realize_and_unref(sysbus, &error_fatal);
+        sysbus_connect_irq(sysbus, 0, PIC_GPIO(VIRT_VIRTIO_IRQ_BASE + i));
+        sysbus_mmio_map(sysbus, 0, io_base);
+        io_base += 0x200;
+    }
+
+    if (kernel_filename) {
+        CPUState *cs = CPU(cpu);
+        uint64_t high;
+
+        kernel_size = load_elf(kernel_filename, NULL, NULL, NULL,
+                               &elf_entry, NULL, &high, NULL, 1,
+                               EM_68K, 0, 0);
+        if (kernel_size < 0) {
+            error_report("could not load kernel '%s'", kernel_filename);
+            exit(1);
+        }
+        stl_phys(cs->as, 4, elf_entry); /* reset initial PC */
+        parameters_base = (high + 1) & ~1;
+
+        BOOTINFO1(cs->as, parameters_base, BI_MACHTYPE, MACH_VIRT);
+        BOOTINFO1(cs->as, parameters_base, BI_FPUTYPE, FPU_68040);
+        BOOTINFO1(cs->as, parameters_base, BI_MMUTYPE, MMU_68040);
+        BOOTINFO1(cs->as, parameters_base, BI_CPUTYPE, CPU_68040);
+        BOOTINFO2(cs->as, parameters_base, BI_MEMCHUNK, 0, ram_size);
+
+        BOOTINFO1(cs->as, parameters_base, BI_VIRT_QEMU_VERSION,
+                  ((QEMU_VERSION_MAJOR << 24) | (QEMU_VERSION_MICRO << 16) |
+                   (QEMU_VERSION_MINOR << 8)));
+        BOOTINFO2(cs->as, parameters_base, BI_VIRT_GF_PIC_BASE,
+                  VIRT_GF_PIC_MMIO_BASE, VIRT_GF_PIC_IRQ_BASE);
+        BOOTINFO2(cs->as, parameters_base, BI_VIRT_GF_RTC_BASE,
+                  VIRT_GF_RTC_MMIO_BASE, VIRT_GF_RTC_IRQ_BASE);
+        BOOTINFO2(cs->as, parameters_base, BI_VIRT_GF_TTY_BASE,
+                  VIRT_GF_TTY_MMIO_BASE, VIRT_GF_TTY_IRQ_BASE);
+        BOOTINFO2(cs->as, parameters_base, BI_VIRT_VIRTIO_BASE,
+                  VIRT_VIRTIO_MMIO_BASE, VIRT_VIRTIO_IRQ_BASE);
+
+        if (kernel_cmdline) {
+            BOOTINFOSTR(cs->as, parameters_base, BI_COMMAND_LINE,
+                        kernel_cmdline);
+        }
+
+        /* load initrd */
+        if (initrd_filename) {
+            initrd_size = get_image_size(initrd_filename);
+            if (initrd_size < 0) {
+                error_report("could not load initial ram disk '%s'",
+                             initrd_filename);
+                exit(1);
+            }
+
+            initrd_base = (ram_size - initrd_size) & TARGET_PAGE_MASK;
+            load_image_targphys(initrd_filename, initrd_base,
+                                ram_size - initrd_base);
+            BOOTINFO2(cs->as, parameters_base, BI_RAMDISK, initrd_base,
+                      initrd_size);
+        } else {
+            initrd_base = 0;
+            initrd_size = 0;
+        }
+        BOOTINFO0(cs->as, parameters_base, BI_LAST);
+    }
+}
+
+static void virt_machine_class_init(ObjectClass *oc, void *data)
+{
+    MachineClass *mc = MACHINE_CLASS(oc);
+    mc->desc = "M68k Virtual Machine";
+    mc->init = virt_init;
+    mc->default_cpu_type = M68K_CPU_TYPE_NAME("m68040");
+    mc->max_cpus = 1;
+    mc->block_default_type = IF_SCSI;
+    mc->default_ram_id = "m68k_virt.ram";
+}
+
+static const TypeInfo virt_machine_typeinfo = {
+    .name       = MACHINE_TYPE_NAME("virt"),
+    .parent     = TYPE_MACHINE,
+    .class_init = virt_machine_class_init,
+};
+
+static void virt_machine_register_types(void)
+{
+    type_register_static(&virt_machine_typeinfo);
+}
+
+type_init(virt_machine_register_types)
diff --git a/MAINTAINERS b/MAINTAINERS
index d0962a22e1b4..b08cf4251246 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1101,6 +1101,15 @@  F: include/hw/nubus/*
 F: include/hw/display/macfb.h
 F: include/hw/block/swim.h
 
+virt
+M: Laurent Vivier <laurent@vivier.eu>
+S: Maintained
+F: hw/m68k/virt.c
+F: hw/char/goldfish_tty.c
+F: hw/intc/goldfish_pic.c
+F: include/hw/char/goldfish_tty.h
+F: include/hw/intc/goldfish_pic.h
+
 MicroBlaze Machines
 -------------------
 petalogix_s3adsp1800
diff --git a/hw/m68k/Kconfig b/hw/m68k/Kconfig
index c757e7dfa48b..f4b3b115270e 100644
--- a/hw/m68k/Kconfig
+++ b/hw/m68k/Kconfig
@@ -22,3 +22,11 @@  config Q800
     select ESCC
     select ESP
     select DP8393X
+
+config M68K_VIRT
+    bool
+    select GOLDFISH_PIC
+    select GOLDFISH_TTY
+    select GOLDFISH_RTC
+    select VIRTIO
+    select VIRTIO_MMIO
diff --git a/hw/m68k/meson.build b/hw/m68k/meson.build
index ca0044c652d3..31248641d301 100644
--- a/hw/m68k/meson.build
+++ b/hw/m68k/meson.build
@@ -3,5 +3,6 @@  m68k_ss.add(when: 'CONFIG_AN5206', if_true: files('an5206.c', 'mcf5206.c'))
 m68k_ss.add(when: 'CONFIG_MCF5208', if_true: files('mcf5208.c', 'mcf_intc.c'))
 m68k_ss.add(when: 'CONFIG_NEXTCUBE', if_true: files('next-kbd.c', 'next-cube.c'))
 m68k_ss.add(when: 'CONFIG_Q800', if_true: files('q800.c'))
+m68k_ss.add(when: 'CONFIG_M68K_VIRT', if_true: files('virt.c'))
 
 hw_arch += {'m68k': m68k_ss}