From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nutanix.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=proofpoint20171006; bh=h1NJIbRguLdzUy9OLkiVyJFm0+t+aOHwiSjQ/nd21Nc=; b=hbTfhF9A3pay0flUAninKYUMV/0XdjMGk70famESK8tKjSXcwOXvg96UT5JIhnaejVA8 IHEcvupaU7U1EMQLjKQNAHw8LjSqhDqERCpV2C0SRdrJrPEYuhIiPpgkUgd89n209ftk BLVHWTDjk0EpB8DjCHYGbygLBiJGXqSwBIT7T3zMwH76xE3y5Nt2UGvStfZCCEiLiseY 7EIVVTCICbmmsmwOfbMILeLsWMkaAFbZWvRuXVPCQ+kEjSJWhGjItNnjapGu/KulfzSs PZ+X9Plf1x7/xeMPD6BrVUTz93KmSj9dnP4g7uFU3oSwJ92F50jzNgG1GYMhE6N4rboO mg== From: Raphael Norwitz Date: Sun, 7 Aug 2022 20:13:13 +0000 Message-ID: <20220807201307.GA32495@raphael-debian-dev> References: <20220802095010.3330793-1-alex.bennee@linaro.org> <20220802095010.3330793-12-alex.bennee@linaro.org> In-Reply-To: <20220802095010.3330793-12-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Language: en-US Content-Type: text/plain; charset=WINDOWS-1252 Content-ID: Content-Transfer-Encoding: quoted-printable Subject: Re: [Virtio-fs] [PATCH v4 11/22] hw/virtio: move vhd->started check into helper and add FIXME List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Alex_Benn=E9e?= Cc: "qemu-devel@nongnu.org" , "slp@redhat.com" , "mst@redhat.com" , "marcandre.lureau@redhat.com" , "stefanha@redhat.com" , "mathieu.poirier@linaro.org" , "viresh.kumar@linaro.org" , Raphael Norwitz , Kevin Wolf , Hanna Reitz , Paolo Bonzini , Fam Zheng , "Dr. David Alan Gilbert" , "open list:Block layer core" , "open list:virtiofs" On Tue, Aug 02, 2022 at 10:49:59AM +0100, Alex Benn=E9e wrote: > The `started` field is manipulated internally within the vhost code > except for one place, vhost-user-blk via f5b22d06fb (vhost: recheck > dev state in the vhost_migration_log routine). Mark that as a FIXME > because it introduces a potential race. I think the referenced fix > should be tracking its state locally. I don't think we can track the state locally. As described in the commit message for f5b22d06fb, the state is used by vhost code in the vhost_migration_log() function so we probably need something at the vhost level. I do agree we shouldn't re-use vdev->started. Maybe we should add another 'active' variable in vhost_dev? I'm happy to send a patch for that. Until we agree on a better solution I'm happy with the FIXME. Reviewed-by: Raphael Norwitz >=20 > Signed-off-by: Alex Benn=E9e > --- > include/hw/virtio/vhost.h | 12 ++++++++++++ > hw/block/vhost-user-blk.c | 10 ++++++++-- > hw/scsi/vhost-scsi.c | 4 ++-- > hw/scsi/vhost-user-scsi.c | 2 +- > hw/virtio/vhost-user-fs.c | 3 ++- > hw/virtio/vhost-user-i2c.c | 4 ++-- > hw/virtio/vhost-user-rng.c | 4 ++-- > hw/virtio/vhost-user-vsock.c | 2 +- > hw/virtio/vhost-vsock-common.c | 3 ++- > hw/virtio/vhost-vsock.c | 2 +- > 10 files changed, 33 insertions(+), 13 deletions(-) >=20 > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h > index 586c5457e2..61b957e927 100644 > --- a/include/hw/virtio/vhost.h > +++ b/include/hw/virtio/vhost.h > @@ -94,6 +94,7 @@ struct vhost_dev { > uint64_t protocol_features; > uint64_t max_queues; > uint64_t backend_cap; > + /* @started: is the vhost device started? */ > bool started; > bool log_enabled; > uint64_t log_size; > @@ -165,6 +166,17 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hde= v, VirtIODevice *vdev); > */ > void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *v= dev); > =20 > +/** > + * vhost_dev_is_started() - report status of vhost device > + * @hdev: common vhost_dev structure > + * > + * Return the started status of the vhost device > + */ > +static inline bool vhost_dev_is_started(struct vhost_dev *hdev) > +{ > + return hdev->started; > +} > + > /** > * vhost_dev_start() - start the vhost device > * @hdev: common vhost_dev structure > diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c > index 9117222456..2bba42478d 100644 > --- a/hw/block/vhost-user-blk.c > +++ b/hw/block/vhost-user-blk.c > @@ -229,7 +229,7 @@ static void vhost_user_blk_set_status(VirtIODevice *v= dev, uint8_t status) > return; > } > =20 > - if (s->dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&s->dev) =3D=3D should_start) { > return; > } > =20 > @@ -286,7 +286,7 @@ static void vhost_user_blk_handle_output(VirtIODevice= *vdev, VirtQueue *vq) > return; > } > =20 > - if (s->dev.started) { > + if (vhost_dev_is_started(&s->dev)) { > return; > } > =20 > @@ -415,6 +415,12 @@ static void vhost_user_blk_event(void *opaque, QEMUC= hrEvent event) > * the vhost migration code. If disconnect was caught there = is an > * option for the general vhost code to get the dev state wi= thout > * knowing its type (in this case vhost-user). > + * > + * FIXME: this is sketchy to be reaching into vhost_dev > + * now because we are forcing something that implies we > + * have executed vhost_dev_stop() but that won't happen > + * until vhost_user_blk_stop() gets called from the bh. > + * Really this state check should be tracked locally. > */ > s->dev.started =3D false; > } > diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c > index 3059068175..bdf337a7a2 100644 > --- a/hw/scsi/vhost-scsi.c > +++ b/hw/scsi/vhost-scsi.c > @@ -120,7 +120,7 @@ static void vhost_scsi_set_status(VirtIODevice *vdev,= uint8_t val) > start =3D false; > } > =20 > - if (vsc->dev.started =3D=3D start) { > + if (vhost_dev_is_started(&vsc->dev) =3D=3D start) { > return; > } > =20 > @@ -147,7 +147,7 @@ static int vhost_scsi_pre_save(void *opaque) > =20 > /* At this point, backend must be stopped, otherwise > * it might keep writing to memory. */ > - assert(!vsc->dev.started); > + assert(!vhost_dev_is_started(&vsc->dev)); > =20 > return 0; > } > diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c > index 1b2f7eed98..bc37317d55 100644 > --- a/hw/scsi/vhost-user-scsi.c > +++ b/hw/scsi/vhost-user-scsi.c > @@ -49,7 +49,7 @@ static void vhost_user_scsi_set_status(VirtIODevice *vd= ev, uint8_t status) > VHostSCSICommon *vsc =3D VHOST_SCSI_COMMON(s); > bool start =3D (status & VIRTIO_CONFIG_S_DRIVER_OK) && vdev->vm_runn= ing; > =20 > - if (vsc->dev.started =3D=3D start) { > + if (vhost_dev_is_started(&vsc->dev) =3D=3D start) { > return; > } > =20 > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > index d2bebba785..ad0f91c607 100644 > --- a/hw/virtio/vhost-user-fs.c > +++ b/hw/virtio/vhost-user-fs.c > @@ -20,6 +20,7 @@ > #include "hw/virtio/virtio-bus.h" > #include "hw/virtio/virtio-access.h" > #include "qemu/error-report.h" > +#include "hw/virtio/vhost.h" > #include "hw/virtio/vhost-user-fs.h" > #include "monitor/monitor.h" > #include "sysemu/sysemu.h" > @@ -124,7 +125,7 @@ static void vuf_set_status(VirtIODevice *vdev, uint8_= t status) > VHostUserFS *fs =3D VHOST_USER_FS(vdev); > bool should_start =3D virtio_device_started(vdev, status); > =20 > - if (fs->vhost_dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&fs->vhost_dev) =3D=3D should_start) { > return; > } > =20 > diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c > index b930cf6d5e..bc58b6c0d1 100644 > --- a/hw/virtio/vhost-user-i2c.c > +++ b/hw/virtio/vhost-user-i2c.c > @@ -95,7 +95,7 @@ static void vu_i2c_set_status(VirtIODevice *vdev, uint8= _t status) > VHostUserI2C *i2c =3D VHOST_USER_I2C(vdev); > bool should_start =3D virtio_device_started(vdev, status); > =20 > - if (i2c->vhost_dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&i2c->vhost_dev) =3D=3D should_start) { > return; > } > =20 > @@ -174,7 +174,7 @@ static void vu_i2c_disconnect(DeviceState *dev) > } > i2c->connected =3D false; > =20 > - if (i2c->vhost_dev.started) { > + if (vhost_dev_is_started(&i2c->vhost_dev)) { > vu_i2c_stop(vdev); > } > } > diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c > index a9c1c4bc79..bc1f36c5ac 100644 > --- a/hw/virtio/vhost-user-rng.c > +++ b/hw/virtio/vhost-user-rng.c > @@ -92,7 +92,7 @@ static void vu_rng_set_status(VirtIODevice *vdev, uint8= _t status) > VHostUserRNG *rng =3D VHOST_USER_RNG(vdev); > bool should_start =3D virtio_device_started(vdev, status); > =20 > - if (rng->vhost_dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&rng->vhost_dev) =3D=3D should_start) { > return; > } > =20 > @@ -160,7 +160,7 @@ static void vu_rng_disconnect(DeviceState *dev) > =20 > rng->connected =3D false; > =20 > - if (rng->vhost_dev.started) { > + if (vhost_dev_is_started(&rng->vhost_dev)) { > vu_rng_stop(vdev); > } > } > diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c > index 22c1616ebd..7b67e29d83 100644 > --- a/hw/virtio/vhost-user-vsock.c > +++ b/hw/virtio/vhost-user-vsock.c > @@ -57,7 +57,7 @@ static void vuv_set_status(VirtIODevice *vdev, uint8_t = status) > VHostVSockCommon *vvc =3D VHOST_VSOCK_COMMON(vdev); > bool should_start =3D virtio_device_started(vdev, status); > =20 > - if (vvc->vhost_dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&vvc->vhost_dev) =3D=3D should_start) { > return; > } > =20 > diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-commo= n.c > index 7394818e00..29b9ab4f72 100644 > --- a/hw/virtio/vhost-vsock-common.c > +++ b/hw/virtio/vhost-vsock-common.c > @@ -14,6 +14,7 @@ > #include "hw/virtio/virtio-access.h" > #include "qemu/error-report.h" > #include "hw/qdev-properties.h" > +#include "hw/virtio/vhost.h" > #include "hw/virtio/vhost-vsock.h" > #include "qemu/iov.h" > #include "monitor/monitor.h" > @@ -199,7 +200,7 @@ int vhost_vsock_common_pre_save(void *opaque) > * At this point, backend must be stopped, otherwise > * it might keep writing to memory. > */ > - assert(!vvc->vhost_dev.started); > + assert(!vhost_dev_is_started(&vvc->vhost_dev)); > =20 > return 0; > } > diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c > index 8031c164a5..7dc3c73931 100644 > --- a/hw/virtio/vhost-vsock.c > +++ b/hw/virtio/vhost-vsock.c > @@ -73,7 +73,7 @@ static void vhost_vsock_set_status(VirtIODevice *vdev, = uint8_t status) > bool should_start =3D virtio_device_started(vdev, status); > int ret; > =20 > - if (vvc->vhost_dev.started =3D=3D should_start) { > + if (vhost_dev_is_started(&vvc->vhost_dev) =3D=3D should_start) { > return; > } > =20 > --=20 > 2.30.2 >