[Qemu-devel] [PATCH v5 4/5] hypertrace: [softmmu] Add QEMU-side proxy to "guest_hypertrace" event

["Lluís Vilanova" <vilanova@ac.upc.edu>]

Uses a virtual device to trigger the hypertrace channel event.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 hypertrace/Makefile.objs |    4 +
 hypertrace/softmmu.c     |  235 ++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/pci/pci.h     |    2 
 3 files changed, 241 insertions(+)
 create mode 100644 hypertrace/softmmu.c

diff --git a/hypertrace/Makefile.objs b/hypertrace/Makefile.objs
index 2bda105c2f..01c56c910c 100644
--- a/hypertrace/Makefile.objs
+++ b/hypertrace/Makefile.objs
@@ -1,10 +1,14 @@
 # -*- mode: makefile -*-
 
 target-obj-$(CONFIG_USER_ONLY) += user.o
+ifdef CONFIG_PCI
+target-obj-$(CONFIG_SOFTMMU) += softmmu.o
+endif
 target-obj-y += common.o
 
 $(obj)/user.o: $(obj)/emit.c
 $(obj)/common.o: $(obj)/emit.c
+$(obj)/softmmu.o: $(obj)/emit.c
 
 $(obj)/emit.c: $(obj)/emit.c-timestamp $(BUILD_DIR)/config-host.mak
 	@cmp $< $@ >/dev/null 2>&1 || cp $< $@
diff --git a/hypertrace/softmmu.c b/hypertrace/softmmu.c
new file mode 100644
index 0000000000..8b98938e01
--- /dev/null
+++ b/hypertrace/softmmu.c
@@ -0,0 +1,235 @@
+/*
+ * QEMU-side management of hypertrace in softmmu emulation.
+ *
+ * Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+/*
+ * Implementation details
+ * ======================
+ *
+ * There are 3 channels, each a BAR of a virtual device that can be used through
+ * MMIO.
+ *
+ *
+ * - Configuration channel: Exposes configuration parameters.
+ *
+ * - Data channel: Lets guests write argument values. Each guest client should
+ *   use a different offset to avoid concurrency problems.
+ *
+ * - Control channel: Triggers the hypertrace event on a write, providing the
+ *   first argument. Offset in the control channel sets the offset in the data
+ *   channel.
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "hypertrace/common.h"
+#include "hypertrace/trace.h"
+#include "hw/pci/pci.h"
+#include "migration/blocker.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+
+
+typedef struct HypertraceState {
+    PCIDevice dev;
+
+    uint64_t max_clients;
+    struct hypertrace_config hconfig;
+
+    MemoryRegion config;
+    void *config_ptr;
+    MemoryRegion data;
+    void *data_ptr;
+    MemoryRegion control;
+    void *control_ptr;
+
+    Error *migration_blocker;
+} HypertraceState;
+
+
+static uint64_t hypertrace_control_io_read(void *opaque, hwaddr addr,
+                                           unsigned size)
+{
+    uint64_t res;
+    HypertraceState *s = opaque;
+    char *mem = &((char *)s->control_ptr)[addr];
+
+    switch (size) {
+    case 1:
+    {
+        res = ((uint8_t *)mem)[0];
+        break;
+    }
+    case 2:
+    {
+        res = ((uint16_t *)mem)[0];
+        break;
+    }
+    case 4:
+    {
+        res = ((uint32_t *)mem)[0];
+        break;
+    }
+    case 8:
+    {
+        res = ((uint64_t *)mem)[0];
+        break;
+    }
+    default:
+        error_report("error: hypertrace: Unexpected read of size %d", size);
+    }
+
+    return res;
+}
+
+static void hypertrace_control_io_write(void *opaque, hwaddr addr,
+                                        uint64_t data, unsigned size)
+{
+    HypertraceState *s = opaque;
+    char *mem = &((char *)s->control_ptr)[addr];
+
+    switch (size) {
+    case 1:
+    {
+        uint8_t *res = (uint8_t *)mem;
+        *res = (uint8_t)data;
+        break;
+    }
+    case 2:
+    {
+        uint16_t *res = (uint16_t *)mem;
+        *res = (uint16_t)data;
+        break;
+    }
+    case 4:
+    {
+        uint32_t *res = (uint32_t *)mem;
+        *res = (uint32_t)data;
+        break;
+    }
+    case 8:
+    {
+        uint64_t *res = (uint64_t *)mem;
+        *res = (uint64_t)data;
+        break;
+    }
+    default:
+        error_report("error: hypertrace: Unexpected write of size %d", size);
+    }
+
+    if ((addr + size) % sizeof(uint64_t) == 0) {
+        uint64_t client = addr / sizeof(uint64_t);
+        uint64_t vcontrol = ((uint64_t *)s->control_ptr)[client];
+        uint64_t *data_ptr = (uint64_t *)s->data_ptr;
+        data_ptr = &data_ptr[client * s->hconfig.client_data_size];
+        hypertrace_emit(current_cpu, vcontrol, data_ptr);
+    }
+}
+
+static const MemoryRegionOps hypertrace_control_ops = {
+    .read = &hypertrace_control_io_read,
+    .write = &hypertrace_control_io_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+    },
+};
+
+
+static void hypertrace_realize(PCIDevice *dev, Error **errp)
+{
+    Error *local_err = NULL;
+    struct hypertrace_config *config;
+    HypertraceState *s = DO_UPCAST(HypertraceState, dev, dev);
+    Error *err = NULL;
+
+    if (s->max_clients < 1) {
+        error_setg(errp, "hypertrace: must have at least one client");
+        return;
+    }
+
+    hypertrace_init_config(&s->hconfig, s->max_clients);
+
+    error_setg(&s->migration_blocker,
+               "The 'hypertrace' device cannot be migrated");
+    migrate_add_blocker(s->migration_blocker, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        error_free(s->migration_blocker);
+        return;
+    }
+
+    pci_set_word(s->dev.config + PCI_COMMAND,
+                 PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
+
+    /* config channel */
+    memory_region_init_ram(&s->config, OBJECT(s), "hypertrace.config",
+                           TARGET_PAGE_SIZE, &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+    pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->config);
+    s->config_ptr = qemu_map_ram_ptr(s->config.ram_block, 0);
+    config = s->config_ptr;
+    config->max_clients = tswap64(s->hconfig.max_clients);
+    config->client_args = tswap64(s->hconfig.client_args);
+    config->client_data_size = tswap64(s->hconfig.client_data_size);
+    config->control_size = tswap64(s->hconfig.control_size);
+    config->data_size = tswap64(s->hconfig.data_size);
+
+    /* data channel */
+    memory_region_init_ram(&s->data, OBJECT(s), "hypertrace.data",
+                           s->hconfig.data_size, &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+    pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->data);
+    s->data_ptr = qemu_map_ram_ptr(s->data.ram_block, 0);
+
+    /* control channel */
+    memory_region_init_io(&s->control, OBJECT(s), &hypertrace_control_ops, s,
+                          "hypertrace.control", s->hconfig.control_size);
+    pci_register_bar(&s->dev, 2, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->control);
+    s->control_ptr = qemu_map_ram_ptr(s->control.ram_block, 0);
+}
+
+
+static Property hypertrace_properties[] = {
+    DEFINE_PROP_UINT64("max-clients", HypertraceState, max_clients, 1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void hypertrace_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->realize = hypertrace_realize;
+    k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
+    k->device_id = PCI_DEVICE_ID_HYPERTRACE;
+    k->class_id = PCI_CLASS_MEMORY_RAM;
+    dc->desc  = "Hypertrace communication channel",
+    dc->props = hypertrace_properties;
+}
+
+static TypeInfo hypertrace_info = {
+    .name          = "hypertrace",
+    .parent        = TYPE_PCI_DEVICE,
+    .instance_size = sizeof(HypertraceState),
+    .class_init    = hypertrace_class_init,
+};
+
+static void hypertrace_register_types(void)
+{
+    type_register_static(&hypertrace_info);
+}
+
+type_init(hypertrace_register_types)
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index e598b095eb..3910a9b89f 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -84,6 +84,8 @@
 #define PCI_DEVICE_ID_VIRTIO_9P          0x1009
 #define PCI_DEVICE_ID_VIRTIO_VSOCK       0x1012
 
+#define PCI_DEVICE_ID_HYPERTRACE         0x10f0
+
 #define PCI_VENDOR_ID_REDHAT             0x1b36
 #define PCI_DEVICE_ID_REDHAT_BRIDGE      0x0001
 #define PCI_DEVICE_ID_REDHAT_SERIAL      0x0002