Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 442 insertions, 0 deletions

diff --git a/hw/misc/edu.c b/hw/misc/edu.c
new file mode 100644
index 000000000..e935c418d
--- /dev/null
+++ b/hw/misc/edu.c
@@ -0,0 +1,442 @@
+/*
+ * QEMU educational PCI device
+ *
+ * Copyright (c) 2012-2015 Jiri Slaby
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "hw/pci/pci.h"
+#include "hw/hw.h"
+#include "hw/pci/msi.h"
+#include "qemu/timer.h"
+#include "qom/object.h"
+#include "qemu/main-loop.h" /* iothread mutex */
+#include "qemu/module.h"
+#include "qapi/visitor.h"
+
+#define TYPE_PCI_EDU_DEVICE "edu"
+typedef struct EduState EduState;
+DECLARE_INSTANCE_CHECKER(EduState, EDU,
+                         TYPE_PCI_EDU_DEVICE)
+
+#define FACT_IRQ        0x00000001
+#define DMA_IRQ         0x00000100
+
+#define DMA_START       0x40000
+#define DMA_SIZE        4096
+
+struct EduState {
+    PCIDevice pdev;
+    MemoryRegion mmio;
+
+    QemuThread thread;
+    QemuMutex thr_mutex;
+    QemuCond thr_cond;
+    bool stopping;
+
+    uint32_t addr4;
+    uint32_t fact;
+#define EDU_STATUS_COMPUTING    0x01
+#define EDU_STATUS_IRQFACT      0x80
+    uint32_t status;
+
+    uint32_t irq_status;
+
+#define EDU_DMA_RUN             0x1
+#define EDU_DMA_DIR(cmd)        (((cmd) & 0x2) >> 1)
+# define EDU_DMA_FROM_PCI       0
+# define EDU_DMA_TO_PCI         1
+#define EDU_DMA_IRQ             0x4
+    struct dma_state {
+        dma_addr_t src;
+        dma_addr_t dst;
+        dma_addr_t cnt;
+        dma_addr_t cmd;
+    } dma;
+    QEMUTimer dma_timer;
+    char dma_buf[DMA_SIZE];
+    uint64_t dma_mask;
+};
+
+static bool edu_msi_enabled(EduState *edu)
+{
+    return msi_enabled(&edu->pdev);
+}
+
+static void edu_raise_irq(EduState *edu, uint32_t val)
+{
+    edu->irq_status |= val;
+    if (edu->irq_status) {
+        if (edu_msi_enabled(edu)) {
+            msi_notify(&edu->pdev, 0);
+        } else {
+            pci_set_irq(&edu->pdev, 1);
+        }
+    }
+}
+
+static void edu_lower_irq(EduState *edu, uint32_t val)
+{
+    edu->irq_status &= ~val;
+
+    if (!edu->irq_status && !edu_msi_enabled(edu)) {
+        pci_set_irq(&edu->pdev, 0);
+    }
+}
+
+static bool within(uint64_t addr, uint64_t start, uint64_t end)
+{
+    return start <= addr && addr < end;
+}
+
+static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start,
+                uint64_t size2)
+{
+    uint64_t end1 = addr + size1;
+    uint64_t end2 = start + size2;
+
+    if (within(addr, start, end2) &&
+            end1 > addr && within(end1, start, end2)) {
+        return;
+    }
+
+    hw_error("EDU: DMA range 0x%016"PRIx64"-0x%016"PRIx64
+             " out of bounds (0x%016"PRIx64"-0x%016"PRIx64")!",
+            addr, end1 - 1, start, end2 - 1);
+}
+
+static dma_addr_t edu_clamp_addr(const EduState *edu, dma_addr_t addr)
+{
+    dma_addr_t res = addr & edu->dma_mask;
+
+    if (addr != res) {
+        printf("EDU: clamping DMA %#.16"PRIx64" to %#.16"PRIx64"!\n", addr, res);
+    }
+
+    return res;
+}
+
+static void edu_dma_timer(void *opaque)
+{
+    EduState *edu = opaque;
+    bool raise_irq = false;
+
+    if (!(edu->dma.cmd & EDU_DMA_RUN)) {
+        return;
+    }
+
+    if (EDU_DMA_DIR(edu->dma.cmd) == EDU_DMA_FROM_PCI) {
+        uint64_t dst = edu->dma.dst;
+        edu_check_range(dst, edu->dma.cnt, DMA_START, DMA_SIZE);
+        dst -= DMA_START;
+        pci_dma_read(&edu->pdev, edu_clamp_addr(edu, edu->dma.src),
+                edu->dma_buf + dst, edu->dma.cnt);
+    } else {
+        uint64_t src = edu->dma.src;
+        edu_check_range(src, edu->dma.cnt, DMA_START, DMA_SIZE);
+        src -= DMA_START;
+        pci_dma_write(&edu->pdev, edu_clamp_addr(edu, edu->dma.dst),
+                edu->dma_buf + src, edu->dma.cnt);
+    }
+
+    edu->dma.cmd &= ~EDU_DMA_RUN;
+    if (edu->dma.cmd & EDU_DMA_IRQ) {
+        raise_irq = true;
+    }
+
+    if (raise_irq) {
+        edu_raise_irq(edu, DMA_IRQ);
+    }
+}
+
+static void dma_rw(EduState *edu, bool write, dma_addr_t *val, dma_addr_t *dma,
+                bool timer)
+{
+    if (write && (edu->dma.cmd & EDU_DMA_RUN)) {
+        return;
+    }
+
+    if (write) {
+        *dma = *val;
+    } else {
+        *val = *dma;
+    }
+
+    if (timer) {
+        timer_mod(&edu->dma_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 100);
+    }
+}
+
+static uint64_t edu_mmio_read(void *opaque, hwaddr addr, unsigned size)
+{
+    EduState *edu = opaque;
+    uint64_t val = ~0ULL;
+
+    if (addr < 0x80 && size != 4) {
+        return val;
+    }
+
+    if (addr >= 0x80 && size != 4 && size != 8) {
+        return val;
+    }
+
+    switch (addr) {
+    case 0x00:
+        val = 0x010000edu;
+        break;
+    case 0x04:
+        val = edu->addr4;
+        break;
+    case 0x08:
+        qemu_mutex_lock(&edu->thr_mutex);
+        val = edu->fact;
+        qemu_mutex_unlock(&edu->thr_mutex);
+        break;
+    case 0x20:
+        val = qatomic_read(&edu->status);
+        break;
+    case 0x24:
+        val = edu->irq_status;
+        break;
+    case 0x80:
+        dma_rw(edu, false, &val, &edu->dma.src, false);
+        break;
+    case 0x88:
+        dma_rw(edu, false, &val, &edu->dma.dst, false);
+        break;
+    case 0x90:
+        dma_rw(edu, false, &val, &edu->dma.cnt, false);
+        break;
+    case 0x98:
+        dma_rw(edu, false, &val, &edu->dma.cmd, false);
+        break;
+    }
+
+    return val;
+}
+
+static void edu_mmio_write(void *opaque, hwaddr addr, uint64_t val,
+                unsigned size)
+{
+    EduState *edu = opaque;
+
+    if (addr < 0x80 && size != 4) {
+        return;
+    }
+
+    if (addr >= 0x80 && size != 4 && size != 8) {
+        return;
+    }
+
+    switch (addr) {
+    case 0x04:
+        edu->addr4 = ~val;
+        break;
+    case 0x08:
+        if (qatomic_read(&edu->status) & EDU_STATUS_COMPUTING) {
+            break;
+        }
+        /* EDU_STATUS_COMPUTING cannot go 0->1 concurrently, because it is only
+         * set in this function and it is under the iothread mutex.
+         */
+        qemu_mutex_lock(&edu->thr_mutex);
+        edu->fact = val;
+        qatomic_or(&edu->status, EDU_STATUS_COMPUTING);
+        qemu_cond_signal(&edu->thr_cond);
+        qemu_mutex_unlock(&edu->thr_mutex);
+        break;
+    case 0x20:
+        if (val & EDU_STATUS_IRQFACT) {
+            qatomic_or(&edu->status, EDU_STATUS_IRQFACT);
+        } else {
+            qatomic_and(&edu->status, ~EDU_STATUS_IRQFACT);
+        }
+        break;
+    case 0x60:
+        edu_raise_irq(edu, val);
+        break;
+    case 0x64:
+        edu_lower_irq(edu, val);
+        break;
+    case 0x80:
+        dma_rw(edu, true, &val, &edu->dma.src, false);
+        break;
+    case 0x88:
+        dma_rw(edu, true, &val, &edu->dma.dst, false);
+        break;
+    case 0x90:
+        dma_rw(edu, true, &val, &edu->dma.cnt, false);
+        break;
+    case 0x98:
+        if (!(val & EDU_DMA_RUN)) {
+            break;
+        }
+        dma_rw(edu, true, &val, &edu->dma.cmd, true);
+        break;
+    }
+}
+
+static const MemoryRegionOps edu_mmio_ops = {
+    .read = edu_mmio_read,
+    .write = edu_mmio_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+
+};
+
+/*
+ * We purposely use a thread, so that users are forced to wait for the status
+ * register.
+ */
+static void *edu_fact_thread(void *opaque)
+{
+    EduState *edu = opaque;
+
+    while (1) {
+        uint32_t val, ret = 1;
+
+        qemu_mutex_lock(&edu->thr_mutex);
+        while ((qatomic_read(&edu->status) & EDU_STATUS_COMPUTING) == 0 &&
+                        !edu->stopping) {
+            qemu_cond_wait(&edu->thr_cond, &edu->thr_mutex);
+        }
+
+        if (edu->stopping) {
+            qemu_mutex_unlock(&edu->thr_mutex);
+            break;
+        }
+
+        val = edu->fact;
+        qemu_mutex_unlock(&edu->thr_mutex);
+
+        while (val > 0) {
+            ret *= val--;
+        }
+
+        /*
+         * We should sleep for a random period here, so that students are
+         * forced to check the status properly.
+         */
+
+        qemu_mutex_lock(&edu->thr_mutex);
+        edu->fact = ret;
+        qemu_mutex_unlock(&edu->thr_mutex);
+        qatomic_and(&edu->status, ~EDU_STATUS_COMPUTING);
+
+        if (qatomic_read(&edu->status) & EDU_STATUS_IRQFACT) {
+            qemu_mutex_lock_iothread();
+            edu_raise_irq(edu, FACT_IRQ);
+            qemu_mutex_unlock_iothread();
+        }
+    }
+
+    return NULL;
+}
+
+static void pci_edu_realize(PCIDevice *pdev, Error **errp)
+{
+    EduState *edu = EDU(pdev);
+    uint8_t *pci_conf = pdev->config;
+
+    pci_config_set_interrupt_pin(pci_conf, 1);
+
+    if (msi_init(pdev, 0, 1, true, false, errp)) {
+        return;
+    }
+
+    timer_init_ms(&edu->dma_timer, QEMU_CLOCK_VIRTUAL, edu_dma_timer, edu);
+
+    qemu_mutex_init(&edu->thr_mutex);
+    qemu_cond_init(&edu->thr_cond);
+    qemu_thread_create(&edu->thread, "edu", edu_fact_thread,
+                       edu, QEMU_THREAD_JOINABLE);
+
+    memory_region_init_io(&edu->mmio, OBJECT(edu), &edu_mmio_ops, edu,
+                    "edu-mmio", 1 * MiB);
+    pci_register_bar(pdev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &edu->mmio);
+}
+
+static void pci_edu_uninit(PCIDevice *pdev)
+{
+    EduState *edu = EDU(pdev);
+
+    qemu_mutex_lock(&edu->thr_mutex);
+    edu->stopping = true;
+    qemu_mutex_unlock(&edu->thr_mutex);
+    qemu_cond_signal(&edu->thr_cond);
+    qemu_thread_join(&edu->thread);
+
+    qemu_cond_destroy(&edu->thr_cond);
+    qemu_mutex_destroy(&edu->thr_mutex);
+
+    timer_del(&edu->dma_timer);
+    msi_uninit(pdev);
+}
+
+static void edu_instance_init(Object *obj)
+{
+    EduState *edu = EDU(obj);
+
+    edu->dma_mask = (1UL << 28) - 1;
+    object_property_add_uint64_ptr(obj, "dma_mask",
+                                   &edu->dma_mask, OBJ_PROP_FLAG_READWRITE);
+}
+
+static void edu_class_init(ObjectClass *class, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(class);
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(class);
+
+    k->realize = pci_edu_realize;
+    k->exit = pci_edu_uninit;
+    k->vendor_id = PCI_VENDOR_ID_QEMU;
+    k->device_id = 0x11e8;
+    k->revision = 0x10;
+    k->class_id = PCI_CLASS_OTHERS;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static void pci_edu_register_types(void)
+{
+    static InterfaceInfo interfaces[] = {
+        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
+        { },
+    };
+    static const TypeInfo edu_info = {
+        .name          = TYPE_PCI_EDU_DEVICE,
+        .parent        = TYPE_PCI_DEVICE,
+        .instance_size = sizeof(EduState),
+        .instance_init = edu_instance_init,
+        .class_init    = edu_class_init,
+        .interfaces = interfaces,
+    };
+
+    type_register_static(&edu_info);
+}
+type_init(pci_edu_register_types)