[RFC] qemu: Add virtio pmem device

From: Pankaj Gupta
Date: Thu Apr 05 2018 - 06:49:39 EST


This patch adds virtio-pmem Qemu device.

This device configures memory address range information with file
backend type. It acts like persistent memory device for KVM guest.
It presents the memory address range to virtio-pmem driver over
virtio channel and does the block flush whenever there is request
from guest to flush/sync. (Qemu part for backing file flush
is yet to be implemented).

Current code is a RFC to support guest with persistent memory
range & DAX.

Signed-off-by: Pankaj Gupta <pagupta@xxxxxxxxxx>
---
hw/virtio/Makefile.objs | 2 +-
hw/virtio/virtio-pci.c | 44 +++++++++
hw/virtio/virtio-pci.h | 14 +++
hw/virtio/virtio-pmem.c | 133 ++++++++++++++++++++++++++++
include/hw/pci/pci.h | 1 +
include/hw/virtio/virtio-pmem.h | 43 +++++++++
include/standard-headers/linux/virtio_ids.h | 1 +
7 files changed, 237 insertions(+), 1 deletion(-)
create mode 100644 hw/virtio/virtio-pmem.c
create mode 100644 include/hw/virtio/virtio-pmem.h

diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index 765d363c1f..bb5573d2ef 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -5,7 +5,7 @@ common-obj-y += virtio-bus.o
common-obj-y += virtio-mmio.o

obj-y += virtio.o virtio-balloon.o
-obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o
+obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o virtio-pmem.o
obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o
obj-y += virtio-crypto.o
obj-$(CONFIG_VIRTIO_PCI) += virtio-crypto-pci.o
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index c20537f31d..114ca05497 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -2491,6 +2491,49 @@ static const TypeInfo virtio_rng_pci_info = {
.class_init = virtio_rng_pci_class_init,
};

+/* virtio-pmem-pci */
+
+static void virtio_pmem_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
+{
+ VirtIOPMEMPCI *vpmem = VIRTIO_PMEM_PCI(vpci_dev);
+ DeviceState *vdev = DEVICE(&vpmem->vdev);
+
+ qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
+ object_property_set_bool(OBJECT(vdev), true, "realized", errp);
+}
+
+static void virtio_pmem_pci_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
+ PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
+ k->realize = virtio_pmem_pci_realize;
+ set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+ pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
+ pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_PMEM;
+ pcidev_k->revision = VIRTIO_PCI_ABI_VERSION;
+ pcidev_k->class_id = PCI_CLASS_OTHERS;
+}
+
+static void virtio_pmem_pci_instance_init(Object *obj)
+{
+ VirtIOPMEMPCI *dev = VIRTIO_PMEM_PCI(obj);
+
+ virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+ TYPE_VIRTIO_PMEM);
+ object_property_add_alias(obj, "memdev", OBJECT(&dev->vdev), "memdev",
+ &error_abort);
+}
+
+static const TypeInfo virtio_pmem_pci_info = {
+ .name = TYPE_VIRTIO_PMEM_PCI,
+ .parent = TYPE_VIRTIO_PCI,
+ .instance_size = sizeof(VirtIOPMEMPCI),
+ .instance_init = virtio_pmem_pci_instance_init,
+ .class_init = virtio_pmem_pci_class_init,
+};
+
+
/* virtio-input-pci */

static Property virtio_input_pci_properties[] = {
@@ -2683,6 +2726,7 @@ static void virtio_pci_register_types(void)
type_register_static(&virtio_balloon_pci_info);
type_register_static(&virtio_serial_pci_info);
type_register_static(&virtio_net_pci_info);
+ type_register_static(&virtio_pmem_pci_info);
#ifdef CONFIG_VHOST_SCSI
type_register_static(&vhost_scsi_pci_info);
#endif
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index 813082b0d7..fe74fcad3f 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -19,6 +19,7 @@
#include "hw/virtio/virtio-blk.h"
#include "hw/virtio/virtio-net.h"
#include "hw/virtio/virtio-rng.h"
+#include "hw/virtio/virtio-pmem.h"
#include "hw/virtio/virtio-serial.h"
#include "hw/virtio/virtio-scsi.h"
#include "hw/virtio/virtio-balloon.h"
@@ -57,6 +58,7 @@ typedef struct VirtIOInputHostPCI VirtIOInputHostPCI;
typedef struct VirtIOGPUPCI VirtIOGPUPCI;
typedef struct VHostVSockPCI VHostVSockPCI;
typedef struct VirtIOCryptoPCI VirtIOCryptoPCI;
+typedef struct VirtIOPMEMPCI VirtIOPMEMPCI;

/* virtio-pci-bus */

@@ -274,6 +276,18 @@ struct VirtIOBlkPCI {
VirtIOBlock vdev;
};

+/*
+ * virtio-pmem-pci: This extends VirtioPCIProxy.
+ */
+#define TYPE_VIRTIO_PMEM_PCI "virtio-pmem-pci"
+#define VIRTIO_PMEM_PCI(obj) \
+ OBJECT_CHECK(VirtIOPMEMPCI, (obj), TYPE_VIRTIO_PMEM_PCI)
+
+struct VirtIOPMEMPCI {
+ VirtIOPCIProxy parent_obj;
+ VirtIOPMEM vdev;
+};
+
/*
* virtio-balloon-pci: This extends VirtioPCIProxy.
*/
diff --git a/hw/virtio/virtio-pmem.c b/hw/virtio/virtio-pmem.c
new file mode 100644
index 0000000000..28d06fc501
--- /dev/null
+++ b/hw/virtio/virtio-pmem.c
@@ -0,0 +1,133 @@
+/*
+ * Virtio pmem device
+ *
+ */
+
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "qemu/error-report.h"
+#include "hw/virtio/virtio-pmem.h"
+
+
+static void virtio_pmem_system_reset(void *opaque)
+{
+
+}
+
+static void virtio_pmem_flush(VirtIODevice *vdev, VirtQueue *vq)
+{
+ VirtQueueElement *elem;
+
+ elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
+ if (!elem) {
+ return;
+ }
+ /* todo flush raw file */
+
+ virtio_notify(vdev, vq);
+ g_free(elem);
+
+}
+
+static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
+{
+ VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
+ struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
+
+ pmemcfg->start = pmem->start;
+ pmemcfg->size = pmem->size;
+ pmemcfg->align = pmem->align;
+}
+
+static uint64_t virtio_pmem_get_features(VirtIODevice *vdev, uint64_t features,
+ Error **errp)
+{
+ virtio_add_feature(&features, VIRTIO_PMEM_PLUG);
+ return features;
+}
+
+
+static void virtio_pmem_realize(DeviceState *dev, Error **errp)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VirtIOPMEM *pmem = VIRTIO_PMEM(dev);
+ MachineState *ms = MACHINE(qdev_get_machine());
+ MemoryRegion *mr;
+ PCMachineState *pcms = PC_MACHINE(object_dynamic_cast(OBJECT(ms), TYPE_PC_MACHINE));
+ uint64_t addr;
+
+ if (!pmem->memdev) {
+ error_setg(errp, "virtio-pmem not set");
+ return;
+ }
+
+ mr = host_memory_backend_get_memory(pmem->memdev, errp);
+ addr = pcms->hotplug_memory.base;
+ pmem->start = addr;
+ pmem->size = memory_region_size(mr);
+ pmem->align = memory_region_get_alignment(mr);
+
+ memory_region_init_alias(&pmem->mr, OBJECT(ms),
+ "virtio_pmem-memory", mr, 0, pmem->size);
+
+ host_memory_backend_set_mapped(pmem->memdev, true);
+ virtio_init(vdev, TYPE_VIRTIO_PMEM, VIRTIO_ID_PMEM,
+ sizeof(struct virtio_pmem_config));
+
+ pmem->rq_vq = virtio_add_queue(vdev, 128, virtio_pmem_flush);
+ qemu_register_reset(virtio_pmem_system_reset, pmem);
+}
+
+static void virtio_mem_check_memdev(Object *obj, const char *name, Object *val,
+ Error **errp)
+{
+ if (host_memory_backend_is_mapped(MEMORY_BACKEND(val))) {
+
+ char *path = object_get_canonical_path_component(val);
+ error_setg(errp, "Can't use already busy memdev: %s", path);
+ g_free(path);
+ return;
+ }
+
+ qdev_prop_allow_set_link_before_realize(obj, name, val, errp);
+}
+
+static void virtio_pmem_instance_init(Object *obj)
+{
+
+ VirtIOPMEM *vm = VIRTIO_PMEM(obj);
+
+ object_property_add_link(obj, "memdev", TYPE_MEMORY_BACKEND,
+ (Object **)&vm->memdev,
+ (void *) virtio_mem_check_memdev,
+ OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ &error_abort);
+}
+
+
+static void virtio_pmem_class_init(ObjectClass *klass, void *data)
+{
+ VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+ vdc->realize = virtio_pmem_realize;
+ vdc->get_config = virtio_pmem_get_config;
+ vdc->get_features = virtio_pmem_get_features;
+}
+
+static TypeInfo virtio_pmem_info = {
+ .name = TYPE_VIRTIO_PMEM,
+ .parent = TYPE_VIRTIO_DEVICE,
+ .class_size = sizeof(VirtIOPMEM),
+ .class_init = virtio_pmem_class_init,
+ .instance_init = virtio_pmem_instance_init,
+};
+
+
+static void virtio_register_types(void)
+{
+ type_register_static(&virtio_pmem_info);
+}
+
+type_init(virtio_register_types)
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 15ced9648c..0f9091e6cc 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -85,6 +85,7 @@ extern bool pci_available;
#define PCI_DEVICE_ID_VIRTIO_RNG 0x1005
#define PCI_DEVICE_ID_VIRTIO_9P 0x1009
#define PCI_DEVICE_ID_VIRTIO_VSOCK 0x1012
+#define PCI_DEVICE_ID_VIRTIO_PMEM 0x1013

#define PCI_VENDOR_ID_REDHAT 0x1b36
#define PCI_DEVICE_ID_REDHAT_BRIDGE 0x0001
diff --git a/include/hw/virtio/virtio-pmem.h b/include/hw/virtio/virtio-pmem.h
new file mode 100644
index 0000000000..f4be2f54f3
--- /dev/null
+++ b/include/hw/virtio/virtio-pmem.h
@@ -0,0 +1,43 @@
+/*
+ * Virtio pmem Device
+ *
+ *
+ */
+
+#ifndef QEMU_VIRTIO_PMEM_H
+#define QEMU_VIRTIO_PMEM_H
+
+#include "hw/virtio/virtio.h"
+#include "exec/memory.h"
+#include "sysemu/hostmem.h"
+#include "standard-headers/linux/virtio_ids.h"
+#include "hw/boards.h"
+#include "hw/i386/pc.h"
+
+#define VIRTIO_PMEM_PLUG 0
+
+#define TYPE_VIRTIO_PMEM "virtio-pmem"
+
+#define VIRTIO_PMEM(obj) \
+ OBJECT_CHECK(VirtIOPMEM, (obj), TYPE_VIRTIO_PMEM)
+
+typedef struct VirtIOPMEM {
+
+ VirtIODevice parent_obj;
+ VirtQueue *rq_vq;
+ uint64_t start;
+ uint64_t size;
+ uint64_t align;
+
+ MemoryRegion mr;
+ HostMemoryBackend *memdev;
+} VirtIOPMEM;
+
+struct virtio_pmem_config {
+
+ uint64_t start;
+ uint64_t size;
+ uint64_t align;
+};
+
+#endif
diff --git a/include/standard-headers/linux/virtio_ids.h b/include/standard-headers/linux/virtio_ids.h
index 6d5c3b2d4f..5ebd04980d 100644
--- a/include/standard-headers/linux/virtio_ids.h
+++ b/include/standard-headers/linux/virtio_ids.h
@@ -43,5 +43,6 @@
#define VIRTIO_ID_INPUT 18 /* virtio input */
#define VIRTIO_ID_VSOCK 19 /* virtio vsock transport */
#define VIRTIO_ID_CRYPTO 20 /* virtio crypto */
+#define VIRTIO_ID_PMEM 21 /* virtio pmem */

#endif /* _LINUX_VIRTIO_IDS_H */
--
2.14.3