On Thu, 22 Oct 2020 23:11:39 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
> On 10/22/2020 10:05 PM, Alex Williamson wrote:
> > 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,
> >
>
> Yup.
> Updated patch 4, 5 and 6. So now vfio_migration_finalize() looks like:
>
> void vfio_migration_finalize(VFIODevice *vbasedev)
> {
> VFIOMigration *migration = vbasedev->migration;
>
> if (migration) {
> if (migration->migration_state.notify) {
>
> remove_migration_state_change_notifier(&migration->migration_state);
> }
>
> if (migration->vm_state) {
> qemu_del_vm_change_state_handler(migration->vm_state);
> }
We should be able to remove these based only on migration being
non-NULL, their setup cannot fail once we've setup the migration
pointer. Thanks,
Alex
>
> vfio_migration_region_exit(vbasedev);
> g_free(vbasedev->migration);
> vbasedev->migration = NULL;
> }
>
> if (vbasedev->migration_blocker) {
> migrate_del_blocker(vbasedev->migration_blocker);
> error_free(vbasedev->migration_blocker);
> vbasedev->migration_blocker = NULL;
> }
> }
>
> Thanks,
> Kirti
>
> > 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 {
> >
>
