On Thu, 22 Oct 2020 16:41:55 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
> VM state change handler is called on change in VM's state. Based on
> VM state, VFIO device state should be changed.
> Added read/write helper functions for migration region.
> Added function to set device_state.
>
> 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 | 158
> ++++++++++++++++++++++++++++++++++++++++++
> hw/vfio/trace-events | 2 +
> include/hw/vfio/vfio-common.h | 4 ++
> 3 files changed, 164 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index 5f74a3ad1d72..34f39c7e2e28 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 +23,157 @@
> #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 byte %s: failed at offset 0x%lx, err:
> %s",
> + iswrite ? "write" : "read", count,
> + vbasedev->name, off, strerror(errno));
> + 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)
> +
> +#define VFIO_MIG_STRUCT_OFFSET(f) \
> + offsetof(struct vfio_device_migration_info,
> f)
> +/*
> + * Change the device_state register for device @vbasedev. Bits set in @mask
> + * are preserved, bits set in @value are set, and bits not set in either
> @mask
> + * or @value are cleared in device_state. If the register cannot be accessed,
> + * the resulting state would be invalid, or the device enters an error state,
> + * an error is returned.
> + */
> +
> +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 +
> + VFIO_MIG_STRUCT_OFFSET(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;
> +
> + 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) {
> + int rret;
> +
> + rret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state),
> + dev_state_off);
> +
> + if ((rret < 0) || (VFIO_DEVICE_STATE_IS_ERROR(device_state))) {
> + hw_error("%s: Device in error state 0x%x", vbasedev->name,
> + device_state);
> + return rret ? rret : -EIO;
> + }
> + return ret;
> + }
> +
> + migration->device_state = device_state;
> + trace_vfio_migration_set_state(vbasedev->name, device_state);
> + return 0;
> +}
> +
> +static void vfio_vmstate_change(void *opaque, int running, RunState state)
> +{
> + VFIODevice *vbasedev = opaque;
> + VFIOMigration *migration = vbasedev->migration;
> + uint32_t value, mask;
> + int ret;
> +
> + if ((vbasedev->migration->vm_running == running)) {
> + return;
> + }
> +
> + if (running) {
> + /*
> + * Here device state can have one of _SAVING, _RESUMING or _STOP bit.
> + * Transition from _SAVING to _RUNNING can happen if there is
> migration
> + * failure, in that case clear _SAVING bit.
> + * Transition from _RESUMING to _RUNNING occurs during resuming
> + * phase, in that case clear _RESUMING bit.
> + * In both the above cases, set _RUNNING bit.
> + */
> + mask = ~VFIO_DEVICE_STATE_MASK;
> + value = VFIO_DEVICE_STATE_RUNNING;
> + } else {
> + /*
> + * Here device state could be either _RUNNING or _SAVING|_RUNNING.
> Reset
> + * _RUNNING bit
> + */
> + mask = ~VFIO_DEVICE_STATE_RUNNING;
> + value = 0;
> + }
> +
> + ret = vfio_migration_set_state(vbasedev, mask, value);
> + if (ret) {
> + /*
> + * Migration should be aborted in this case, but vm_state_notify()
> + * currently does not support reporting failures.
> + */
> + error_report("%s: Failed to set device state 0x%x", vbasedev->name,
> + (migration->device_state & mask) | value);
> + qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
> + }
> + vbasedev->migration->vm_running = running;
> + trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
> + (migration->device_state & mask) | value);
> +}
>
> static void vfio_migration_region_exit(VFIODevice *vbasedev)
> {
> @@ -71,6 +223,8 @@ static int vfio_migration_init(VFIODevice *vbasedev,
> }
>
> vbasedev->migration = migration;
> + migration->vm_state =
> qemu_add_vm_change_state_handler(vfio_vmstate_change,
> + vbasedev);
> return 0;
>
> err:
> @@ -118,6 +272,10 @@ add_blocker:
>
> void vfio_migration_finalize(VFIODevice *vbasedev)
> {
> + if (vbasedev->migration->vm_state) {
> + qemu_del_vm_change_state_handler(vbasedev->migration->vm_state);
> + }
This looks like a segfault, vfio_migration_teardown() is eventually
called unconditionally. The next patch modifies this function further,
but never checks that vbasedev->migration is non-NULL. Thanks,
Alex
> +
> 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 9ced5ec6277c..41de81f12f60 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -148,3 +148,5 @@ vfio_display_edid_write_error(void) ""
>
> # migration.c
> vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d"
> +vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d"
> +vfio_vmstate_change(const 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..9a571f1fb552 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: "
>
> @@ -58,7 +59,10 @@ typedef struct VFIORegion {
> } VFIORegion;
>
> typedef struct VFIOMigration {
> + VMChangeStateEntry *vm_state;
> VFIORegion region;
> + uint32_t device_state;
> + int vm_running;
> } VFIOMigration;
>
> typedef struct VFIOAddressSpace {
