hw/arm: Add 'virt' platform

Add 'virt' platform support corresponding to arch/arm/mach-virt
in the Linux kernel tree. This has no platform-specific code but
can use any device whose kernel driver is is able to work purely
from a device tree node. We use this to instantiate a minimal
set of devices: a GIC and some virtio-mmio transports.

Signed-off-by: John Rigby <john.rigby@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Message-id: 1385140638-10444-8-git-send-email-peter.maydell@linaro.org
[PMM:
 Significantly overhauled:
 * renamed user-facing machine to just "virt"
 * removed the A9 support (it can't work since the A9 has no
   generic timers)
 * added virtio-mmio transports instead of random set of 'soc' devices
   (though we retain a pl011 UART)
 * instead of updating io_base as we step through adding devices,
   define a memory map with an array (similar to vexpress)
 * similarly, define irqmap with an array
 * folded in some minor fixes from John's aarch64-support patch
 * rather than explicitly doing endian-swapping on FDT cells,
   use fdt APIs that let us just pass in host-endian values
   and let the fdt layer take care of the swapping
 * miscellaneous minor code cleanups and style fixes
]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 445 insertions, 1 deletions

diff --git a/hw/arm/Makefile.objs b/hw/arm/Makefile.objs
index 3671b42738..78b56149b6 100644
--- a/hw/arm/Makefile.objs
+++ b/hw/arm/Makefile.objs
@@ -1,7 +1,7 @@
 obj-y += boot.o collie.o exynos4_boards.o gumstix.o highbank.o
 obj-y += integratorcp.o kzm.o mainstone.o musicpal.o nseries.o
 obj-y += omap_sx1.o palm.o realview.o spitz.o stellaris.o
-obj-y += tosa.o versatilepb.o vexpress.o xilinx_zynq.o z2.o
+obj-y += tosa.o versatilepb.o vexpress.o virt.o xilinx_zynq.o z2.o
 
 obj-y += armv7m.o exynos4210.o pxa2xx.o pxa2xx_gpio.o pxa2xx_pic.o
 obj-y += omap1.o omap2.o strongarm.o
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
new file mode 100644
index 0000000000..1e42cc2666
--- /dev/null
+++ b/hw/arm/virt.c
@@ -0,0 +1,444 @@
+/*
+ * ARM mach-virt emulation
+ *
+ * Copyright (c) 2013 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Emulate a virtual board which works by passing Linux all the information
+ * it needs about what devices are present via the device tree.
+ * There are some restrictions about what we can do here:
+ *  + we can only present devices whose Linux drivers will work based
+ *    purely on the device tree with no platform data at all
+ *  + we want to present a very stripped-down minimalist platform,
+ *    both because this reduces the security attack surface from the guest
+ *    and also because it reduces our exposure to being broken when
+ *    the kernel updates its device tree bindings and requires further
+ *    information in a device binding that we aren't providing.
+ * This is essentially the same approach kvmtool uses.
+ */
+
+#include "hw/sysbus.h"
+#include "hw/arm/arm.h"
+#include "hw/arm/primecell.h"
+#include "hw/devices.h"
+#include "net/net.h"
+#include "sysemu/device_tree.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/kvm.h"
+#include "hw/boards.h"
+#include "exec/address-spaces.h"
+#include "qemu/bitops.h"
+#include "qemu/error-report.h"
+
+#define NUM_VIRTIO_TRANSPORTS 32
+
+/* Number of external interrupt lines to configure the GIC with */
+#define NUM_IRQS 128
+
+#define GIC_FDT_IRQ_TYPE_SPI 0
+#define GIC_FDT_IRQ_TYPE_PPI 1
+
+#define GIC_FDT_IRQ_FLAGS_EDGE_LO_HI 1
+#define GIC_FDT_IRQ_FLAGS_EDGE_HI_LO 2
+#define GIC_FDT_IRQ_FLAGS_LEVEL_HI 4
+#define GIC_FDT_IRQ_FLAGS_LEVEL_LO 8
+
+#define GIC_FDT_IRQ_PPI_CPU_START 8
+#define GIC_FDT_IRQ_PPI_CPU_WIDTH 8
+
+enum {
+    VIRT_FLASH,
+    VIRT_MEM,
+    VIRT_CPUPERIPHS,
+    VIRT_GIC_DIST,
+    VIRT_GIC_CPU,
+    VIRT_UART,
+    VIRT_MMIO,
+};
+
+typedef struct MemMapEntry {
+    hwaddr base;
+    hwaddr size;
+} MemMapEntry;
+
+typedef struct VirtBoardInfo {
+    struct arm_boot_info bootinfo;
+    const char *cpu_model;
+    const char *qdevname;
+    const char *gic_compatible;
+    const MemMapEntry *memmap;
+    const int *irqmap;
+    int smp_cpus;
+    void *fdt;
+    int fdt_size;
+    uint32_t clock_phandle;
+} VirtBoardInfo;
+
+/* Addresses and sizes of our components.
+ * 0..128MB is space for a flash device so we can run bootrom code such as UEFI.
+ * 128MB..256MB is used for miscellaneous device I/O.
+ * 256MB..1GB is reserved for possible future PCI support (ie where the
+ * PCI memory window will go if we add a PCI host controller).
+ * 1GB and up is RAM (which may happily spill over into the
+ * high memory region beyond 4GB).
+ * This represents a compromise between how much RAM can be given to
+ * a 32 bit VM and leaving space for expansion and in particular for PCI.
+ */
+static const MemMapEntry a15memmap[] = {
+    /* Space up to 0x8000000 is reserved for a boot ROM */
+    [VIRT_FLASH] = { 0, 0x8000000 },
+    [VIRT_CPUPERIPHS] = { 0x8000000, 0x8000 },
+    /* GIC distributor and CPU interfaces sit inside the CPU peripheral space */
+    [VIRT_GIC_DIST] = { 0x8001000, 0x1000 },
+    [VIRT_GIC_CPU] = { 0x8002000, 0x1000 },
+    [VIRT_UART] = { 0x9000000, 0x1000 },
+    [VIRT_MMIO] = { 0xa000000, 0x200 },
+    /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size */
+    /* 0x10000000 .. 0x40000000 reserved for PCI */
+    [VIRT_MEM] = { 0x40000000, 30ULL * 1024 * 1024 * 1024 },
+};
+
+static const int a15irqmap[] = {
+    [VIRT_UART] = 1,
+    [VIRT_MMIO] = 16, /* ...to 16 + NUM_VIRTIO_TRANSPORTS - 1 */
+};
+
+static VirtBoardInfo machines[] = {
+    {
+        .cpu_model = "cortex-a15",
+        .qdevname = "a15mpcore_priv",
+        .gic_compatible = "arm,cortex-a15-gic",
+        .memmap = a15memmap,
+        .irqmap = a15irqmap,
+    },
+};
+
+static VirtBoardInfo *find_machine_info(const char *cpu)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(machines); i++) {
+        if (strcmp(cpu, machines[i].cpu_model) == 0) {
+            return &machines[i];
+        }
+    }
+    return NULL;
+}
+
+static void create_fdt(VirtBoardInfo *vbi)
+{
+    void *fdt = create_device_tree(&vbi->fdt_size);
+
+    if (!fdt) {
+        error_report("create_device_tree() failed");
+        exit(1);
+    }
+
+    vbi->fdt = fdt;
+
+    /* Header */
+    qemu_devtree_setprop_string(fdt, "/", "compatible", "linux,dummy-virt");
+    qemu_devtree_setprop_cell(fdt, "/", "#address-cells", 0x2);
+    qemu_devtree_setprop_cell(fdt, "/", "#size-cells", 0x2);
+
+    /*
+     * /chosen and /memory nodes must exist for load_dtb
+     * to fill in necessary properties later
+     */
+    qemu_devtree_add_subnode(fdt, "/chosen");
+    qemu_devtree_add_subnode(fdt, "/memory");
+    qemu_devtree_setprop_string(fdt, "/memory", "device_type", "memory");
+
+    /* Clock node, for the benefit of the UART. The kernel device tree
+     * binding documentation claims the PL011 node clock properties are
+     * optional but in practice if you omit them the kernel refuses to
+     * probe for the device.
+     */
+    vbi->clock_phandle = qemu_devtree_alloc_phandle(fdt);
+    qemu_devtree_add_subnode(fdt, "/apb-pclk");
+    qemu_devtree_setprop_string(fdt, "/apb-pclk", "compatible", "fixed-clock");
+    qemu_devtree_setprop_cell(fdt, "/apb-pclk", "#clock-cells", 0x0);
+    qemu_devtree_setprop_cell(fdt, "/apb-pclk", "clock-frequency", 24000000);
+    qemu_devtree_setprop_string(fdt, "/apb-pclk", "clock-output-names",
+                                "clk24mhz");
+    qemu_devtree_setprop_cell(fdt, "/apb-pclk", "phandle", vbi->clock_phandle);
+
+    /* No PSCI for TCG yet */
+    if (kvm_enabled()) {
+        qemu_devtree_add_subnode(fdt, "/psci");
+        qemu_devtree_setprop_string(fdt, "/psci", "compatible", "arm,psci");
+        qemu_devtree_setprop_string(fdt, "/psci", "method", "hvc");
+        qemu_devtree_setprop_cell(fdt, "/psci", "cpu_suspend",
+                                  PSCI_FN_CPU_SUSPEND);
+        qemu_devtree_setprop_cell(fdt, "/psci", "cpu_off", PSCI_FN_CPU_OFF);
+        qemu_devtree_setprop_cell(fdt, "/psci", "cpu_on", PSCI_FN_CPU_ON);
+        qemu_devtree_setprop_cell(fdt, "/psci", "migrate", PSCI_FN_MIGRATE);
+    }
+}
+
+static void fdt_add_timer_nodes(const VirtBoardInfo *vbi)
+{
+    /* Note that on A15 h/w these interrupts are level-triggered,
+     * but for the GIC implementation provided by both QEMU and KVM
+     * they are edge-triggered.
+     */
+    uint32_t irqflags = GIC_FDT_IRQ_FLAGS_EDGE_LO_HI;
+
+    irqflags = deposit32(irqflags, GIC_FDT_IRQ_PPI_CPU_START,
+                         GIC_FDT_IRQ_PPI_CPU_WIDTH, (1 << vbi->smp_cpus) - 1);
+
+    qemu_devtree_add_subnode(vbi->fdt, "/timer");
+    qemu_devtree_setprop_string(vbi->fdt, "/timer",
+                                "compatible", "arm,armv7-timer");
+    qemu_devtree_setprop_cells(vbi->fdt, "/timer", "interrupts",
+                               GIC_FDT_IRQ_TYPE_PPI, 13, irqflags,
+                               GIC_FDT_IRQ_TYPE_PPI, 14, irqflags,
+                               GIC_FDT_IRQ_TYPE_PPI, 11, irqflags,
+                               GIC_FDT_IRQ_TYPE_PPI, 10, irqflags);
+}
+
+static void fdt_add_cpu_nodes(const VirtBoardInfo *vbi)
+{
+    int cpu;
+
+    qemu_devtree_add_subnode(vbi->fdt, "/cpus");
+    qemu_devtree_setprop_cell(vbi->fdt, "/cpus", "#address-cells", 0x1);
+    qemu_devtree_setprop_cell(vbi->fdt, "/cpus", "#size-cells", 0x0);
+
+    for (cpu = vbi->smp_cpus - 1; cpu >= 0; cpu--) {
+        char *nodename = g_strdup_printf("/cpus/cpu@%d", cpu);
+        ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(cpu));
+
+        qemu_devtree_add_subnode(vbi->fdt, nodename);
+        qemu_devtree_setprop_string(vbi->fdt, nodename, "device_type", "cpu");
+        qemu_devtree_setprop_string(vbi->fdt, nodename, "compatible",
+                                    armcpu->dtb_compatible);
+
+        if (vbi->smp_cpus > 1) {
+            qemu_devtree_setprop_string(vbi->fdt, nodename,
+                                        "enable-method", "psci");
+        }
+
+        qemu_devtree_setprop_cell(vbi->fdt, nodename, "reg", cpu);
+        g_free(nodename);
+    }
+}
+
+static void fdt_add_gic_node(const VirtBoardInfo *vbi)
+{
+    uint32_t gic_phandle;
+
+    gic_phandle = qemu_devtree_alloc_phandle(vbi->fdt);
+    qemu_devtree_setprop_cell(vbi->fdt, "/", "interrupt-parent", gic_phandle);
+
+    qemu_devtree_add_subnode(vbi->fdt, "/intc");
+    qemu_devtree_setprop_string(vbi->fdt, "/intc", "compatible",
+                                vbi->gic_compatible);
+    qemu_devtree_setprop_cell(vbi->fdt, "/intc", "#interrupt-cells", 3);
+    qemu_devtree_setprop(vbi->fdt, "/intc", "interrupt-controller", NULL, 0);
+    qemu_devtree_setprop_sized_cells(vbi->fdt, "/intc", "reg",
+                                     2, vbi->memmap[VIRT_GIC_DIST].base,
+                                     2, vbi->memmap[VIRT_GIC_DIST].size,
+                                     2, vbi->memmap[VIRT_GIC_CPU].base,
+                                     2, vbi->memmap[VIRT_GIC_CPU].size);
+    qemu_devtree_setprop_cell(vbi->fdt, "/intc", "phandle", gic_phandle);
+}
+
+static void create_uart(const VirtBoardInfo *vbi, qemu_irq *pic)
+{
+    char *nodename;
+    hwaddr base = vbi->memmap[VIRT_UART].base;
+    hwaddr size = vbi->memmap[VIRT_UART].size;
+    int irq = vbi->irqmap[VIRT_UART];
+    const char compat[] = "arm,pl011\0arm,primecell";
+    const char clocknames[] = "uartclk\0apb_pclk";
+
+    sysbus_create_simple("pl011", base, pic[irq]);
+
+    nodename = g_strdup_printf("/pl011@%" PRIx64, base);
+    qemu_devtree_add_subnode(vbi->fdt, nodename);
+    /* Note that we can't use setprop_string because of the embedded NUL */
+    qemu_devtree_setprop(vbi->fdt, nodename, "compatible",
+                         compat, sizeof(compat));
+    qemu_devtree_setprop_sized_cells(vbi->fdt, nodename, "reg",
+                                     2, base, 2, size);
+    qemu_devtree_setprop_cells(vbi->fdt, nodename, "interrupts",
+                               GIC_FDT_IRQ_TYPE_SPI, irq,
+                               GIC_FDT_IRQ_FLAGS_EDGE_LO_HI);
+    qemu_devtree_setprop_cells(vbi->fdt, nodename, "clocks",
+                               vbi->clock_phandle, vbi->clock_phandle);
+    qemu_devtree_setprop(vbi->fdt, nodename, "clock-names",
+                         clocknames, sizeof(clocknames));
+    g_free(nodename);
+}
+
+static void create_virtio_devices(const VirtBoardInfo *vbi, qemu_irq *pic)
+{
+    int i;
+    hwaddr size = vbi->memmap[VIRT_MMIO].size;
+
+    /* Note that we have to create the transports in forwards order
+     * so that command line devices are inserted lowest address first,
+     * and then add dtb nodes in reverse order so that they appear in
+     * the finished device tree lowest address first.
+     */
+    for (i = 0; i < NUM_VIRTIO_TRANSPORTS; i++) {
+        int irq = vbi->irqmap[VIRT_MMIO] + i;
+        hwaddr base = vbi->memmap[VIRT_MMIO].base + i * size;
+
+        sysbus_create_simple("virtio-mmio", base, pic[irq]);
+    }
+
+    for (i = NUM_VIRTIO_TRANSPORTS - 1; i >= 0; i--) {
+        char *nodename;
+        int irq = vbi->irqmap[VIRT_MMIO] + i;
+        hwaddr base = vbi->memmap[VIRT_MMIO].base + i * size;
+
+        nodename = g_strdup_printf("/virtio_mmio@%" PRIx64, base);
+        qemu_devtree_add_subnode(vbi->fdt, nodename);
+        qemu_devtree_setprop_string(vbi->fdt, nodename,
+                                    "compatible", "virtio,mmio");
+        qemu_devtree_setprop_sized_cells(vbi->fdt, nodename, "reg",
+                                         2, base, 2, size);
+        qemu_devtree_setprop_cells(vbi->fdt, nodename, "interrupts",
+                                   GIC_FDT_IRQ_TYPE_SPI, irq,
+                                   GIC_FDT_IRQ_FLAGS_EDGE_LO_HI);
+        g_free(nodename);
+    }
+}
+
+static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)
+{
+    const VirtBoardInfo *board = (const VirtBoardInfo *)binfo;
+
+    *fdt_size = board->fdt_size;
+    return board->fdt;
+}
+
+static void machvirt_init(QEMUMachineInitArgs *args)
+{
+    qemu_irq pic[NUM_IRQS];
+    MemoryRegion *sysmem = get_system_memory();
+    int n;
+    MemoryRegion *ram = g_new(MemoryRegion, 1);
+    DeviceState *dev;
+    SysBusDevice *busdev;
+    const char *cpu_model = args->cpu_model;
+    VirtBoardInfo *vbi;
+
+    if (!cpu_model) {
+        cpu_model = "cortex-a15";
+    }
+
+    vbi = find_machine_info(cpu_model);
+
+    if (!vbi) {
+        error_report("mach-virt: CPU %s not supported", cpu_model);
+        exit(1);
+    }
+
+    vbi->smp_cpus = smp_cpus;
+
+    /*
+     * Only supported method of starting secondary CPUs is PSCI and
+     * PSCI is not yet supported with TCG, so limit smp_cpus to 1
+     * if we're not using KVM.
+     */
+    if (!kvm_enabled() && smp_cpus > 1) {
+        error_report("mach-virt: must enable KVM to use multiple CPUs");
+        exit(1);
+    }
+
+    if (args->ram_size > vbi->memmap[VIRT_MEM].size) {
+        error_report("mach-virt: cannot model more than 30GB RAM");
+        exit(1);
+    }
+
+    create_fdt(vbi);
+    fdt_add_timer_nodes(vbi);
+
+    for (n = 0; n < smp_cpus; n++) {
+        ObjectClass *oc = cpu_class_by_name(TYPE_ARM_CPU, cpu_model);
+        Object *cpuobj;
+
+        if (!oc) {
+            fprintf(stderr, "Unable to find CPU definition\n");
+            exit(1);
+        }
+        cpuobj = object_new(object_class_get_name(oc));
+
+        /* Secondary CPUs start in PSCI powered-down state */
+        if (n > 0) {
+            object_property_set_bool(cpuobj, true, "start-powered-off", NULL);
+        }
+        object_property_set_bool(cpuobj, true, "realized", NULL);
+    }
+    fdt_add_cpu_nodes(vbi);
+
+    memory_region_init_ram(ram, NULL, "mach-virt.ram", args->ram_size);
+    vmstate_register_ram_global(ram);
+    memory_region_add_subregion(sysmem, vbi->memmap[VIRT_MEM].base, ram);
+
+    dev = qdev_create(NULL, vbi->qdevname);
+    qdev_prop_set_uint32(dev, "num-cpu", smp_cpus);
+    /* Note that the num-irq property counts both internal and external
+     * interrupts; there are always 32 of the former (mandated by GIC spec).
+     */
+    qdev_prop_set_uint32(dev, "num-irq", NUM_IRQS + 32);
+    qdev_init_nofail(dev);
+    busdev = SYS_BUS_DEVICE(dev);
+    sysbus_mmio_map(busdev, 0, vbi->memmap[VIRT_CPUPERIPHS].base);
+    fdt_add_gic_node(vbi);
+    for (n = 0; n < smp_cpus; n++) {
+        DeviceState *cpudev = DEVICE(qemu_get_cpu(n));
+
+        sysbus_connect_irq(busdev, n, qdev_get_gpio_in(cpudev, ARM_CPU_IRQ));
+    }
+
+    for (n = 0; n < NUM_IRQS; n++) {
+        pic[n] = qdev_get_gpio_in(dev, n);
+    }
+
+    create_uart(vbi, pic);
+
+    /* Create mmio transports, so the user can create virtio backends
+     * (which will be automatically plugged in to the transports). If
+     * no backend is created the transport will just sit harmlessly idle.
+     */
+    create_virtio_devices(vbi, pic);
+
+    vbi->bootinfo.ram_size = args->ram_size;
+    vbi->bootinfo.kernel_filename = args->kernel_filename;
+    vbi->bootinfo.kernel_cmdline = args->kernel_cmdline;
+    vbi->bootinfo.initrd_filename = args->initrd_filename;
+    vbi->bootinfo.nb_cpus = smp_cpus;
+    vbi->bootinfo.board_id = -1;
+    vbi->bootinfo.loader_start = vbi->memmap[VIRT_MEM].base;
+    vbi->bootinfo.get_dtb = machvirt_dtb;
+    arm_load_kernel(ARM_CPU(first_cpu), &vbi->bootinfo);
+}
+
+static QEMUMachine machvirt_a15_machine = {
+    .name = "virt",
+    .desc = "ARM Virtual Machine",
+    .init = machvirt_init,
+    .max_cpus = 4,
+};
+
+static void machvirt_machine_init(void)
+{
+    qemu_register_machine(&machvirt_a15_machine);
+}
+
+machine_init(machvirt_machine_init);