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. > + 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. > + > + 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? > + } > + > + 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. > +} > + > +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. > + 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, Alex > } VFIODevice; > > struct VFIODeviceOps {