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From: Alex Williamson <alex.williamson@redhat.com>
To: qemu-devel@nongnu.org
Cc: Artem Polyakov <artemp@nvidia.com>,
	Yan Zhao <yan.y.zhao@intel.com>,
	Kirti Wankhede <kwankhede@nvidia.com>, Neo Jia <cjia@nvidia.com>,
	Zhi Wang <zhi.wang.linux@gmail.com>
Subject: [PULL 08/32] vfio: Add save state functions to SaveVMHandlers
Date: Mon, 26 Oct 2020 13:33:37 -0600
Message-ID: <160374081749.22414.8462899562917230404.stgit@gimli.home> (raw)
In-Reply-To: <160374054442.22414.10832953989449611268.stgit@gimli.home>

From: Kirti Wankhede <kwankhede@nvidia.com>

Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy
functions. These functions handles pre-copy and stop-and-copy phase.

In _SAVING|_RUNNING device state or pre-copy phase:
- read pending_bytes. If pending_bytes > 0, go through below steps.
- read data_offset - indicates kernel driver to write data to staging
  buffer.
- read data_size - amount of data in bytes written by vendor driver in
  migration region.
- read data_size bytes of data from data_offset in the migration region.
- Write data packet to file stream as below:
{VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data,
VFIO_MIG_FLAG_END_OF_STATE }

In _SAVING device state or stop-and-copy phase
a. read config space of device and save to migration file stream. This
   doesn't need to be from vendor driver. Any other special config state
   from driver can be saved as data in following iteration.
b. read pending_bytes. If pending_bytes > 0, go through below steps.
c. read data_offset - indicates kernel driver to write data to staging
   buffer.
d. read data_size - amount of data in bytes written by vendor driver in
   migration region.
e. read data_size bytes of data from data_offset in the migration region.
f. Write data packet as below:
   {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data}
g. iterate through steps b to f while (pending_bytes > 0)
h. Write {VFIO_MIG_FLAG_END_OF_STATE}

When data region is mapped, its user's responsibility to read data from
data_offset of data_size before moving to next steps.

Added fix suggested by Artem Polyakov to reset pending_bytes in
vfio_save_iterate().
Added fix suggested by Zhi Wang to add 0 as data size in migration stream and
add END_OF_STATE delimiter to indicate phase complete.

Suggested-by: Artem Polyakov <artemp@nvidia.com>
Suggested-by: Zhi Wang <zhi.wang.linux@gmail.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/migration.c           |  276 +++++++++++++++++++++++++++++++++++++++++
 hw/vfio/trace-events          |    6 +
 include/hw/vfio/vfio-common.h |    1 
 3 files changed, 283 insertions(+)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index d3ef9e18f39c..41d568558479 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -148,6 +148,151 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask,
     return 0;
 }
 
+static void *get_data_section_size(VFIORegion *region, uint64_t data_offset,
+                                   uint64_t data_size, uint64_t *size)
+{
+    void *ptr = NULL;
+    uint64_t limit = 0;
+    int i;
+
+    if (!region->mmaps) {
+        if (size) {
+            *size = MIN(data_size, region->size - data_offset);
+        }
+        return ptr;
+    }
+
+    for (i = 0; i < region->nr_mmaps; i++) {
+        VFIOMmap *map = region->mmaps + i;
+
+        if ((data_offset >= map->offset) &&
+            (data_offset < map->offset + map->size)) {
+
+            /* check if data_offset is within sparse mmap areas */
+            ptr = map->mmap + data_offset - map->offset;
+            if (size) {
+                *size = MIN(data_size, map->offset + map->size - data_offset);
+            }
+            break;
+        } else if ((data_offset < map->offset) &&
+                   (!limit || limit > map->offset)) {
+            /*
+             * data_offset is not within sparse mmap areas, find size of
+             * non-mapped area. Check through all list since region->mmaps list
+             * is not sorted.
+             */
+            limit = map->offset;
+        }
+    }
+
+    if (!ptr && size) {
+        *size = limit ? MIN(data_size, limit - data_offset) : data_size;
+    }
+    return ptr;
+}
+
+static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev, uint64_t *size)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    VFIORegion *region = &migration->region;
+    uint64_t data_offset = 0, data_size = 0, sz;
+    int ret;
+
+    ret = vfio_mig_read(vbasedev, &data_offset, sizeof(data_offset),
+                      region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_offset));
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = vfio_mig_read(vbasedev, &data_size, sizeof(data_size),
+                        region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_size));
+    if (ret < 0) {
+        return ret;
+    }
+
+    trace_vfio_save_buffer(vbasedev->name, data_offset, data_size,
+                           migration->pending_bytes);
+
+    qemu_put_be64(f, data_size);
+    sz = data_size;
+
+    while (sz) {
+        void *buf;
+        uint64_t sec_size;
+        bool buf_allocated = false;
+
+        buf = get_data_section_size(region, data_offset, sz, &sec_size);
+
+        if (!buf) {
+            buf = g_try_malloc(sec_size);
+            if (!buf) {
+                error_report("%s: Error allocating buffer ", __func__);
+                return -ENOMEM;
+            }
+            buf_allocated = true;
+
+            ret = vfio_mig_read(vbasedev, buf, sec_size,
+                                region->fd_offset + data_offset);
+            if (ret < 0) {
+                g_free(buf);
+                return ret;
+            }
+        }
+
+        qemu_put_buffer(f, buf, sec_size);
+
+        if (buf_allocated) {
+            g_free(buf);
+        }
+        sz -= sec_size;
+        data_offset += sec_size;
+    }
+
+    ret = qemu_file_get_error(f);
+
+    if (!ret && size) {
+        *size = data_size;
+    }
+
+    return ret;
+}
+
+static int vfio_update_pending(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    VFIORegion *region = &migration->region;
+    uint64_t pending_bytes = 0;
+    int ret;
+
+    ret = vfio_mig_read(vbasedev, &pending_bytes, sizeof(pending_bytes),
+                    region->fd_offset + VFIO_MIG_STRUCT_OFFSET(pending_bytes));
+    if (ret < 0) {
+        migration->pending_bytes = 0;
+        return ret;
+    }
+
+    migration->pending_bytes = pending_bytes;
+    trace_vfio_update_pending(vbasedev->name, pending_bytes);
+    return 0;
+}
+
+static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
+
+    if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
+        vbasedev->ops->vfio_save_config(vbasedev, f);
+    }
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+    trace_vfio_save_device_config_state(vbasedev->name);
+
+    return qemu_file_get_error(f);
+}
+
 static void vfio_migration_cleanup(VFIODevice *vbasedev)
 {
     VFIOMigration *migration = vbasedev->migration;
@@ -210,9 +355,140 @@ static void vfio_save_cleanup(void *opaque)
     trace_vfio_save_cleanup(vbasedev->name);
 }
 
+static void vfio_save_pending(QEMUFile *f, void *opaque,
+                              uint64_t threshold_size,
+                              uint64_t *res_precopy_only,
+                              uint64_t *res_compatible,
+                              uint64_t *res_postcopy_only)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    int ret;
+
+    ret = vfio_update_pending(vbasedev);
+    if (ret) {
+        return;
+    }
+
+    *res_precopy_only += migration->pending_bytes;
+
+    trace_vfio_save_pending(vbasedev->name, *res_precopy_only,
+                            *res_postcopy_only, *res_compatible);
+}
+
+static int vfio_save_iterate(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    uint64_t data_size;
+    int ret;
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
+
+    if (migration->pending_bytes == 0) {
+        ret = vfio_update_pending(vbasedev);
+        if (ret) {
+            return ret;
+        }
+
+        if (migration->pending_bytes == 0) {
+            qemu_put_be64(f, 0);
+            qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+            /* indicates data finished, goto complete phase */
+            return 1;
+        }
+    }
+
+    ret = vfio_save_buffer(f, vbasedev, &data_size);
+    if (ret) {
+        error_report("%s: vfio_save_buffer failed %s", vbasedev->name,
+                     strerror(errno));
+        return ret;
+    }
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+    ret = qemu_file_get_error(f);
+    if (ret) {
+        return ret;
+    }
+
+    /*
+     * Reset pending_bytes as .save_live_pending is not called during savevm or
+     * snapshot case, in such case vfio_update_pending() at the start of this
+     * function updates pending_bytes.
+     */
+    migration->pending_bytes = 0;
+    trace_vfio_save_iterate(vbasedev->name, data_size);
+    return 0;
+}
+
+static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    uint64_t data_size;
+    int ret;
+
+    ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_RUNNING,
+                                   VFIO_DEVICE_STATE_SAVING);
+    if (ret) {
+        error_report("%s: Failed to set state STOP and SAVING",
+                     vbasedev->name);
+        return ret;
+    }
+
+    ret = vfio_save_device_config_state(f, opaque);
+    if (ret) {
+        return ret;
+    }
+
+    ret = vfio_update_pending(vbasedev);
+    if (ret) {
+        return ret;
+    }
+
+    while (migration->pending_bytes > 0) {
+        qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
+        ret = vfio_save_buffer(f, vbasedev, &data_size);
+        if (ret < 0) {
+            error_report("%s: Failed to save buffer", vbasedev->name);
+            return ret;
+        }
+
+        if (data_size == 0) {
+            break;
+        }
+
+        ret = vfio_update_pending(vbasedev);
+        if (ret) {
+            return ret;
+        }
+    }
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+    ret = qemu_file_get_error(f);
+    if (ret) {
+        return ret;
+    }
+
+    ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_SAVING, 0);
+    if (ret) {
+        error_report("%s: Failed to set state STOPPED", vbasedev->name);
+        return ret;
+    }
+
+    trace_vfio_save_complete_precopy(vbasedev->name);
+    return ret;
+}
+
 static SaveVMHandlers savevm_vfio_handlers = {
     .save_setup = vfio_save_setup,
     .save_cleanup = vfio_save_cleanup,
+    .save_live_pending = vfio_save_pending,
+    .save_live_iterate = vfio_save_iterate,
+    .save_live_complete_precopy = vfio_save_complete_precopy,
 };
 
 /* ---------------------------------------------------------------------- */
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index f148b5e828c1..9f5712dab1ea 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -153,3 +153,9 @@ vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t
 vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s"
 vfio_save_setup(const char *name) " (%s)"
 vfio_save_cleanup(const char *name) " (%s)"
+vfio_save_buffer(const char *name, uint64_t data_offset, uint64_t data_size, uint64_t pending) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64" pending 0x%"PRIx64
+vfio_update_pending(const char *name, uint64_t pending) " (%s) pending 0x%"PRIx64
+vfio_save_device_config_state(const char *name) " (%s)"
+vfio_save_pending(const char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64
+vfio_save_iterate(const char *name, int data_size) " (%s) data_size %d"
+vfio_save_complete_precopy(const char *name) " (%s)"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 2bd593ba38bb..f4ebdae013ad 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -65,6 +65,7 @@ typedef struct VFIOMigration {
     uint32_t device_state;
     int vm_running;
     Notifier migration_state;
+    uint64_t pending_bytes;
 } VFIOMigration;
 
 typedef struct VFIOAddressSpace {



  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-26 19:32 [PULL 00/32] VFIO updates 2020-10-26 (for QEMU 5.2 soft-freeze) Alex Williamson
2020-10-26 19:32 ` [PULL 01/32] vfio: Add function to unmap VFIO region Alex Williamson
2020-10-26 19:32 ` [PULL 02/32] vfio: Add vfio_get_object callback to VFIODeviceOps Alex Williamson
2020-10-26 19:32 ` [PULL 03/32] vfio: Add save and load functions for VFIO PCI devices Alex Williamson
2020-10-26 19:32 ` [PULL 04/32] vfio: Add migration region initialization and finalize function Alex Williamson
2020-10-26 19:33 ` [PULL 05/32] vfio: Add VM state change handler to know state of VM Alex Williamson
2020-10-26 19:33 ` [PULL 06/32] vfio: Add migration state change notifier Alex Williamson
2020-10-26 19:33 ` [PULL 07/32] vfio: Register SaveVMHandlers for VFIO device Alex Williamson
2020-10-26 19:33 ` Alex Williamson [this message]
2020-10-26 19:33 ` [PULL 09/32] vfio: Add load state functions to SaveVMHandlers Alex Williamson
2020-10-26 19:33 ` [PULL 10/32] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Alex Williamson
2020-10-26 19:34 ` [PULL 11/32] vfio: Get migration capability flags for container Alex Williamson
2020-10-26 19:34 ` [PULL 12/32] vfio: Add function to start and stop dirty pages tracking Alex Williamson
2020-10-26 19:34 ` [PULL 13/32] vfio: Add vfio_listener_log_sync to mark dirty pages Alex Williamson
2020-10-26 19:34 ` [PULL 14/32] vfio: Dirty page tracking when vIOMMU is enabled Alex Williamson
2020-10-26 19:34 ` [PULL 15/32] vfio: Add ioctl to get dirty pages bitmap during dma unmap Alex Williamson
2020-10-26 19:34 ` [PULL 16/32] vfio: Make vfio-pci device migration capable Alex Williamson
2020-10-26 19:34 ` [PULL 17/32] qapi: Add VFIO devices migration stats in Migration stats Alex Williamson
2020-10-26 19:35 ` [PULL 18/32] update-linux-headers: Add vfio_zdev.h Alex Williamson
2020-10-26 19:35 ` [PULL 19/32] linux-headers: update against 5.10-rc1 Alex Williamson
2020-10-26 19:35 ` [PULL 20/32] s390x/pci: Move header files to include/hw/s390x Alex Williamson
2020-10-26 19:35 ` [PULL 21/32] vfio: Create shared routine for scanning info capabilities Alex Williamson
2020-10-26 19:35 ` [PULL 22/32] vfio: Find DMA available capability Alex Williamson
2020-10-26 19:35 ` [PULL 23/32] s390x/pci: Add routine to get the vfio dma available count Alex Williamson
2020-10-26 19:35 ` [PULL 24/32] s390x/pci: Honor DMA limits set by vfio Alex Williamson
2020-10-26 19:35 ` [PULL 25/32] s390x/pci: create a header dedicated to PCI CLP Alex Williamson
2020-10-26 19:36 ` [PULL 26/32] s390x/pci: use a PCI Group structure Alex Williamson
2020-10-26 19:36 ` [PULL 27/32] s390x/pci: clean up s390 PCI groups Alex Williamson
2020-10-26 19:36 ` [PULL 28/32] s390x/pci: use a PCI Function structure Alex Williamson
2020-10-26 19:36 ` [PULL 29/32] vfio: Add routine for finding VFIO_DEVICE_GET_INFO capabilities Alex Williamson
2020-10-26 19:36 ` [PULL 30/32] s390x/pci: get zPCI function info from host Alex Williamson
2020-10-26 19:36 ` [PULL 31/32] hw/vfio: Use lock guard macros Alex Williamson
2020-10-26 19:36 ` [PULL 32/32] vfio: fix incorrect print type Alex Williamson
2020-10-27 23:42 ` [PULL 00/32] VFIO updates 2020-10-26 (for QEMU 5.2 soft-freeze) Peter Maydell
2020-10-28  2:00   ` Alex Williamson
2020-10-28  9:18     ` Dr. David Alan Gilbert
2020-10-28 15:23       ` Miklos Szeredi
2020-10-28  9:21     ` Max Reitz
2020-10-28  8:11   ` Cornelia Huck
2020-10-28  9:28     ` Max Reitz
2020-10-28  9:41       ` Max Reitz
2020-10-28 10:12       ` Cornelia Huck
2020-10-28 15:07 ` Peter Maydell
2020-10-28 15:20   ` Matthew Rosato
2020-10-28 15:41     ` Alex Williamson

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