Re: [PATCH v27 07/17] vfio: Register SaveVMHandlers for VFIO device
On 10/23/2020 12:21 AM, Alex Williamson wrote:
On Thu, 22 Oct 2020 16:41:57 +0530
Kirti Wankhede wrote:
Define flags to be used as delimiter in migration stream for VFIO devices.
Added .save_setup and .save_cleanup functions. Map & unmap migration
region from these functions at source during saving or pre-copy phase.
Set VFIO device state depending on VM's state. During live migration, VM is
running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO
device. During save-restore, VM is paused, _SAVING state is set for VFIO device.
Signed-off-by: Kirti Wankhede
Reviewed-by: Neo Jia
---
hw/vfio/migration.c | 96
hw/vfio/trace-events | 2 ++
2 files changed, 98 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 7c4fa0d08ea6..2e1054bf7f43 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -8,12 +8,15 @@
*/
#include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
#include
#include "sysemu/runstate.h"
#include "hw/vfio/vfio-common.h"
#include "cpu.h"
#include "migration/migration.h"
+#include "migration/vmstate.h"
#include "migration/qemu-file.h"
#include "migration/register.h"
#include "migration/blocker.h"
@@ -25,6 +28,22 @@
#include "trace.h"
#include "hw/hw.h"
+/*
+ * Flags to be used as unique delimiters for VFIO devices in the migration
+ * stream. These flags are composed as:
+ * 0x => MSB 32-bit all 1s
+ * 0xef10 => Magic ID, represents emulated (virtual) function IO
+ * 0x => 16-bits reserved for flags
+ *
+ * The beginning of state information is marked by _DEV_CONFIG_STATE,
+ * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
+ * certain state information is marked by _END_OF_STATE.
+ */
+#define VFIO_MIG_FLAG_END_OF_STATE (0xef11ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xef12ULL)
+#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xef13ULL)
+#define VFIO_MIG_FLAG_DEV_DATA_STATE(0xef14ULL)
+
static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
off_t off, bool iswrite)
{
@@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
uint32_t mask,
return 0;
}
+/* -- */
+
+static int vfio_save_setup(QEMUFile *f, void *opaque)
+{
+VFIODevice *vbasedev = opaque;
+VFIOMigration *migration = vbasedev->migration;
+int ret;
+
+trace_vfio_save_setup(vbasedev->name);
+
+qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
+
+if (migration->region.mmaps) {
+/*
+ * vfio_region_mmap() called from migration thread. Memory API called
+ * from vfio_regio_mmap() need it when called from outdide the main
loop
+ * thread.
+ */
Thanks for adding this detail, maybe refine slightly as:
Calling vfio_region_mmap() from migration thread. Memory APIs called
from this function require locking the iothread when called from
outside the main loop thread.
Does that capture the intent?
Ok.
+qemu_mutex_lock_iothread();
+ret = vfio_region_mmap(&migration->region);
+qemu_mutex_unlock_iothread();
+if (ret) {
+error_report("%s: Failed to mmap VFIO migration region: %s",
+ vbasedev->name, strerror(-ret));
+error_report("%s: Falling back to slow path", vbasedev->name);
+}
+}
+
+ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
+ VFIO_DEVICE_STATE_SAVING);
+if (ret) {
+error_report("%s: Failed to set state SAVING", vbasedev->name);
+return ret;
+}
+
+qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+ret = qemu_file_get_error(f);
+if (ret) {
+return ret;
+}
+
+return 0;
+}
+
+static void vfio_save_cleanup(void *opaque)
+{
+VFIODevice *vbasedev = opaque;
+VFIOMigration *migration = vbasedev->migration;
+
+if (migration->region.mmaps) {
+vfio_region_unmap(&migration->region);
+}
Are we in a different thread context here that we don't need that same
iothread locking?
qemu_savevm_state_setup() is called without holding iothread lock and
qemu_savevm_state_cleanup() is called holding iothread lock, so we don't
need lock here.
+trace_vfio_save_cleanup(vbasedev->name);
+}
+
+static SaveVMHandlers savevm_vfio_handlers = {
+.save_setup = vfio_save_setup,
+.save_cleanup = vfio_save_cleanup,
+};
+
+/* -- */
+
static void vfio_vmstate_change(void *opaque, int running, RunState state)
{
VFIODevice *vbasedev = opaque;
@@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
int ret;
Object *obj;
VFIOM
Re: [PATCH v27 07/17] vfio: Register SaveVMHandlers for VFIO device
On Thu, 22 Oct 2020 16:41:57 +0530
Kirti Wankhede wrote:
> Define flags to be used as delimiter in migration stream for VFIO devices.
> Added .save_setup and .save_cleanup functions. Map & unmap migration
> region from these functions at source during saving or pre-copy phase.
>
> Set VFIO device state depending on VM's state. During live migration, VM is
> running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO
> device. During save-restore, VM is paused, _SAVING state is set for VFIO
> device.
>
> Signed-off-by: Kirti Wankhede
> Reviewed-by: Neo Jia
> ---
> hw/vfio/migration.c | 96
>
> hw/vfio/trace-events | 2 ++
> 2 files changed, 98 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index 7c4fa0d08ea6..2e1054bf7f43 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -8,12 +8,15 @@
> */
>
> #include "qemu/osdep.h"
> +#include "qemu/main-loop.h"
> +#include "qemu/cutils.h"
> #include
>
> #include "sysemu/runstate.h"
> #include "hw/vfio/vfio-common.h"
> #include "cpu.h"
> #include "migration/migration.h"
> +#include "migration/vmstate.h"
> #include "migration/qemu-file.h"
> #include "migration/register.h"
> #include "migration/blocker.h"
> @@ -25,6 +28,22 @@
> #include "trace.h"
> #include "hw/hw.h"
>
> +/*
> + * Flags to be used as unique delimiters for VFIO devices in the migration
> + * stream. These flags are composed as:
> + * 0x => MSB 32-bit all 1s
> + * 0xef10 => Magic ID, represents emulated (virtual) function IO
> + * 0x => 16-bits reserved for flags
> + *
> + * The beginning of state information is marked by _DEV_CONFIG_STATE,
> + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
> + * certain state information is marked by _END_OF_STATE.
> + */
> +#define VFIO_MIG_FLAG_END_OF_STATE (0xef11ULL)
> +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xef12ULL)
> +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xef13ULL)
> +#define VFIO_MIG_FLAG_DEV_DATA_STATE(0xef14ULL)
> +
> static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
>off_t off, bool iswrite)
> {
> @@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice
> *vbasedev, uint32_t mask,
> return 0;
> }
>
> +/* -- */
> +
> +static int vfio_save_setup(QEMUFile *f, void *opaque)
> +{
> +VFIODevice *vbasedev = opaque;
> +VFIOMigration *migration = vbasedev->migration;
> +int ret;
> +
> +trace_vfio_save_setup(vbasedev->name);
> +
> +qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
> +
> +if (migration->region.mmaps) {
> +/*
> + * vfio_region_mmap() called from migration thread. Memory API called
> + * from vfio_regio_mmap() need it when called from outdide the main
> loop
> + * thread.
> + */
Thanks for adding this detail, maybe refine slightly as:
Calling vfio_region_mmap() from migration thread. Memory APIs called
from this function require locking the iothread when called from
outside the main loop thread.
Does that capture the intent?
> +qemu_mutex_lock_iothread();
> +ret = vfio_region_mmap(&migration->region);
> +qemu_mutex_unlock_iothread();
> +if (ret) {
> +error_report("%s: Failed to mmap VFIO migration region: %s",
> + vbasedev->name, strerror(-ret));
> +error_report("%s: Falling back to slow path", vbasedev->name);
> +}
> +}
> +
> +ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
> + VFIO_DEVICE_STATE_SAVING);
> +if (ret) {
> +error_report("%s: Failed to set state SAVING", vbasedev->name);
> +return ret;
> +}
> +
> +qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> +
> +ret = qemu_file_get_error(f);
> +if (ret) {
> +return ret;
> +}
> +
> +return 0;
> +}
> +
> +static void vfio_save_cleanup(void *opaque)
> +{
> +VFIODevice *vbasedev = opaque;
> +VFIOMigration *migration = vbasedev->migration;
> +
> +if (migration->region.mmaps) {
> +vfio_region_unmap(&migration->region);
> +}
Are we in a different thread context here that we don't need that same
iothread locking?
> +trace_vfio_save_cleanup(vbasedev->name);
> +}
> +
> +static SaveVMHandlers savevm_vfio_handlers = {
> +.save_setup = vfio_save_setup,
> +.save_cleanup = vfio_save_cleanup,
> +};
> +
> +/* -- */
> +
> static void vfio_vmstate_change(void *opaque, int running, RunState state)
> {
> VFIODevice *vbasedev = opaque;
> @@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
> int ret;
> Object *obj;
>
[PATCH v27 07/17] vfio: Register SaveVMHandlers for VFIO device
Define flags to be used as delimiter in migration stream for VFIO devices.
Added .save_setup and .save_cleanup functions. Map & unmap migration
region from these functions at source during saving or pre-copy phase.
Set VFIO device state depending on VM's state. During live migration, VM is
running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO
device. During save-restore, VM is paused, _SAVING state is set for VFIO device.
Signed-off-by: Kirti Wankhede
Reviewed-by: Neo Jia
---
hw/vfio/migration.c | 96
hw/vfio/trace-events | 2 ++
2 files changed, 98 insertions(+)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 7c4fa0d08ea6..2e1054bf7f43 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -8,12 +8,15 @@
*/
#include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
#include
#include "sysemu/runstate.h"
#include "hw/vfio/vfio-common.h"
#include "cpu.h"
#include "migration/migration.h"
+#include "migration/vmstate.h"
#include "migration/qemu-file.h"
#include "migration/register.h"
#include "migration/blocker.h"
@@ -25,6 +28,22 @@
#include "trace.h"
#include "hw/hw.h"
+/*
+ * Flags to be used as unique delimiters for VFIO devices in the migration
+ * stream. These flags are composed as:
+ * 0x => MSB 32-bit all 1s
+ * 0xef10 => Magic ID, represents emulated (virtual) function IO
+ * 0x => 16-bits reserved for flags
+ *
+ * The beginning of state information is marked by _DEV_CONFIG_STATE,
+ * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
+ * certain state information is marked by _END_OF_STATE.
+ */
+#define VFIO_MIG_FLAG_END_OF_STATE (0xef11ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xef12ULL)
+#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xef13ULL)
+#define VFIO_MIG_FLAG_DEV_DATA_STATE(0xef14ULL)
+
static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
off_t off, bool iswrite)
{
@@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
uint32_t mask,
return 0;
}
+/* -- */
+
+static int vfio_save_setup(QEMUFile *f, void *opaque)
+{
+VFIODevice *vbasedev = opaque;
+VFIOMigration *migration = vbasedev->migration;
+int ret;
+
+trace_vfio_save_setup(vbasedev->name);
+
+qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
+
+if (migration->region.mmaps) {
+/*
+ * vfio_region_mmap() called from migration thread. Memory API called
+ * from vfio_regio_mmap() need it when called from outdide the main
loop
+ * thread.
+ */
+qemu_mutex_lock_iothread();
+ret = vfio_region_mmap(&migration->region);
+qemu_mutex_unlock_iothread();
+if (ret) {
+error_report("%s: Failed to mmap VFIO migration region: %s",
+ vbasedev->name, strerror(-ret));
+error_report("%s: Falling back to slow path", vbasedev->name);
+}
+}
+
+ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
+ VFIO_DEVICE_STATE_SAVING);
+if (ret) {
+error_report("%s: Failed to set state SAVING", vbasedev->name);
+return ret;
+}
+
+qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+ret = qemu_file_get_error(f);
+if (ret) {
+return ret;
+}
+
+return 0;
+}
+
+static void vfio_save_cleanup(void *opaque)
+{
+VFIODevice *vbasedev = opaque;
+VFIOMigration *migration = vbasedev->migration;
+
+if (migration->region.mmaps) {
+vfio_region_unmap(&migration->region);
+}
+trace_vfio_save_cleanup(vbasedev->name);
+}
+
+static SaveVMHandlers savevm_vfio_handlers = {
+.save_setup = vfio_save_setup,
+.save_cleanup = vfio_save_cleanup,
+};
+
+/* -- */
+
static void vfio_vmstate_change(void *opaque, int running, RunState state)
{
VFIODevice *vbasedev = opaque;
@@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
int ret;
Object *obj;
VFIOMigration *migration;
+char id[256] = "";
+g_autofree char *path = NULL, *oid;
if (!vbasedev->ops->vfio_get_object) {
return -EINVAL;
@@ -248,6 +332,18 @@ static int vfio_migration_init(VFIODevice *vbasedev,
vbasedev->migration = migration;
migration->vbasedev = vbasedev;
+
+oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
+if (oid) {
+path = g_strdup_printf("%s/vfio", oid);
+} else {
+path = g_strdup("vfio");
+}
+strpadcpy(id, sizeof(id), path, '\0');
+
+register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
+ vbasedev);
+
migration->vm_state = qem
