On 9/26/2020 1:50 AM, Alex Williamson wrote:
On Wed, 23 Sep 2020 04:54:07 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
VM state change handler gets called on change in VM's state. This is used to set
VFIO device state to _RUNNING.
Signed-off-by: Kirti Wankhede <kwankh...@nvidia.com>
Reviewed-by: Neo Jia <c...@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
hw/vfio/migration.c | 136 ++++++++++++++++++++++++++++++++++++++++++
hw/vfio/trace-events | 3 +-
include/hw/vfio/vfio-common.h | 4 ++
3 files changed, 142 insertions(+), 1 deletion(-)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 2f760f1f9c47..a30d628ba963 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -10,6 +10,7 @@
#include "qemu/osdep.h"
#include <linux/vfio.h>
+#include "sysemu/runstate.h"
#include "hw/vfio/vfio-common.h"
#include "cpu.h"
#include "migration/migration.h"
@@ -22,6 +23,58 @@
#include "exec/ram_addr.h"
#include "pci.h"
#include "trace.h"
+#include "hw/hw.h"
+
+static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
+ off_t off, bool iswrite)
+{
+ int ret;
+
+ ret = iswrite ? pwrite(vbasedev->fd, val, count, off) :
+ pread(vbasedev->fd, val, count, off);
+ if (ret < count) {
+ error_report("vfio_mig_%s%d %s: failed at offset 0x%lx, err: %s",
+ iswrite ? "write" : "read", count * 8,
+ vbasedev->name, off, strerror(errno));
This would suggest from the log that there's, for example, a
vfio_mig_read8 function, which doesn't exist.
Changing to:
error_report("vfio_mig_%s %d byte %s: failed at offset 0x%lx, err: %s",
iswrite ? "write" : "read", count,
vbasedev->name, off, strerror(errno));
Hope this address your concern.
+ return (ret < 0) ? ret : -EINVAL;
+ }
+ return 0;
+}
+
+static int vfio_mig_rw(VFIODevice *vbasedev, __u8 *buf, size_t count,
+ off_t off, bool iswrite)
+{
+ int ret, done = 0;
+ __u8 *tbuf = buf;
+
+ while (count) {
+ int bytes = 0;
+
+ if (count >= 8 && !(off % 8)) {
+ bytes = 8;
+ } else if (count >= 4 && !(off % 4)) {
+ bytes = 4;
+ } else if (count >= 2 && !(off % 2)) {
+ bytes = 2;
+ } else {
+ bytes = 1;
+ }
+
+ ret = vfio_mig_access(vbasedev, tbuf, bytes, off, iswrite);
+ if (ret) {
+ return ret;
+ }
+
+ count -= bytes;
+ done += bytes;
+ off += bytes;
+ tbuf += bytes;
+ }
+ return done;
+}
+
+#define vfio_mig_read(f, v, c, o) vfio_mig_rw(f, (__u8 *)v, c, o, false)
+#define vfio_mig_write(f, v, c, o) vfio_mig_rw(f, (__u8 *)v, c, o, true)
static void vfio_migration_region_exit(VFIODevice *vbasedev)
{
@@ -70,6 +123,82 @@ err:
return ret;
}
+static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask,
+ uint32_t value)
+{
+ VFIOMigration *migration = vbasedev->migration;
+ VFIORegion *region = &migration->region;
+ off_t dev_state_off = region->fd_offset +
+ offsetof(struct vfio_device_migration_info,
device_state);
+ uint32_t device_state;
+ int ret;
+
+ ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state),
+ dev_state_off);
+ if (ret < 0) {
+ return ret;
+ }
+
+ device_state = (device_state & mask) | value;
Agree with Connie that mask and value args are not immediately obvious
how they're used. I don't have a naming convention that would be more
clear and the names do make some sense once they're understood, but a
comment to indicate mask bits are preserved, value bits are set,
remaining bits are cleared would probably help the reader.
Added comment.
+
+ if (!VFIO_DEVICE_STATE_VALID(device_state)) {
+ return -EINVAL;
+ }
+
+ ret = vfio_mig_write(vbasedev, &device_state, sizeof(device_state),
+ dev_state_off);
+ if (ret < 0) {
+ ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state),
+ dev_state_off);
+ if (ret < 0) {
+ return ret;
Seems like we're in pretty bad shape here, should this be combined with
below to trigger a hw_error?
Ok.
+ }
+
+ if (VFIO_DEVICE_STATE_IS_ERROR(device_state)) {
+ hw_error("%s: Device is in error state 0x%x",
+ vbasedev->name, device_state);
+ return -EFAULT;
+ }
+ }
+
+ vbasedev->device_state = device_state;
+ trace_vfio_migration_set_state(vbasedev->name, device_state);
+ return 0;
So we return success even if we failed to write the desired state as
long as we were able to read back any non-error state?
vbasedev->device_state remains correct, but it seems confusing form a
caller perspective that a set-state can succeed but it's then necessary
to check the state.
Correcting here. If vfio_mig_write() had retured error, return error
from vfio_migration_set_state()
+}
+
+static void vfio_vmstate_change(void *opaque, int running, RunState state)
+{
+ VFIODevice *vbasedev = opaque;
+
+ if ((vbasedev->vm_running != running)) {
+ int ret;
+ uint32_t value = 0, mask = 0;
+
+ if (running) {
+ value = VFIO_DEVICE_STATE_RUNNING;
+ if (vbasedev->device_state & VFIO_DEVICE_STATE_RESUMING) {
+ mask = ~VFIO_DEVICE_STATE_RESUMING;
+ }
+ } else {
+ mask = ~VFIO_DEVICE_STATE_RUNNING;
+ }
+
+ ret = vfio_migration_set_state(vbasedev, mask, value);
+ if (ret) {
+ /*
+ * vm_state_notify() doesn't support reporting failure. If such
+ * error reporting support added in furure, migration should be
+ * aborted.
+ */
+ error_report("%s: Failed to set device state 0x%x",
+ vbasedev->name, value & mask);
+ }
Here for instance we assume that success means the device is now in the
desired state, but we'd actually need to evaluate
vbasedev->device_state to determine that.
Updating.
+ vbasedev->vm_running = running;
+ trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
+ value & mask);
+ }
+}
+
static int vfio_migration_init(VFIODevice *vbasedev,
struct vfio_region_info *info)
{
@@ -87,8 +216,11 @@ static int vfio_migration_init(VFIODevice *vbasedev,
vbasedev->name);
g_free(vbasedev->migration);
vbasedev->migration = NULL;
+ return ret;
}
+ vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
+ vbasedev);
return ret;
}
@@ -131,6 +263,10 @@ add_blocker:
void vfio_migration_finalize(VFIODevice *vbasedev)
{
+ if (vbasedev->vm_state) {
+ qemu_del_vm_change_state_handler(vbasedev->vm_state);
+ }
+
if (vbasedev->migration_blocker) {
migrate_del_blocker(vbasedev->migration_blocker);
error_free(vbasedev->migration_blocker);
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 8fe913175d85..6524734bf7b4 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -149,4 +149,5 @@ vfio_display_edid_write_error(void) ""
# migration.c
vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d"
-
+vfio_migration_set_state(char *name, uint32_t state) " (%s) state %d"
+vfio_vmstate_change(char *name, int running, const char *reason, uint32_t dev_state)
" (%s) running %d reason %s device state %d"
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 8275c4c68f45..25e3b1a3b90a 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -29,6 +29,7 @@
#ifdef CONFIG_LINUX
#include <linux/vfio.h>
#endif
+#include "sysemu/sysemu.h"
#define VFIO_MSG_PREFIX "vfio %s: "
@@ -119,6 +120,9 @@ typedef struct VFIODevice {
unsigned int flags;
VFIOMigration *migration;
Error *migration_blocker;
+ VMChangeStateEntry *vm_state;
+ uint32_t device_state;
+ int vm_running;
Could these be placed in VFIOMigration? Thanks,
I think device_state should be part of VFIODevice since its about device
rather than only related to migration, others can be moved to VFIOMigration.
Thanks,
Kirti
Alex
} VFIODevice;
struct VFIODeviceOps {