| Message ID | 20231121221023.419901-2-volodymyr_babchuk@epam.com |
|---|---|
| State | New |
| Headers | show |
| Series | xen-arm: add support for virtio-pci | expand |
On 21/11/2023 22:10, Volodymyr Babchuk wrote: > From: David Woodhouse <dwmw@amazon.co.uk> > > This allows a XenDevice implementation to know whether it was created > by QEMU, or merely discovered in XenStore after the toolstack created > it. This will allow us to create frontend/backend nodes only when we > should, rather than unconditionally attempting to overwrite them from > a driver domain which doesn't have privileges to do so. > > As an added benefit, it also means we no longer have to call the > xen_backend_set_device() function from the device models immediately > after calling qdev_realize_and_unref(). Even though we could make > the argument that it's safe to do so, and the pointer to the unreffed > device *will* actually still be valid, it still made my skin itch to > look at it. > > Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> > --- > hw/block/xen-block.c | 3 +-- > hw/char/xen_console.c | 2 +- > hw/net/xen_nic.c | 2 +- > hw/xen/xen-bus.c | 4 ++++ > include/hw/xen/xen-backend.h | 2 -- > include/hw/xen/xen-bus.h | 2 ++ > 6 files changed, 9 insertions(+), 6 deletions(-) > Reviewed-by: Paul Durrant <paul@xen.org>
On 21/11/2023 22:10, Volodymyr Babchuk wrote: > From: David Woodhouse <dwmw@amazon.co.uk> > > This allows a XenDevice implementation to know whether it was created > by QEMU, or merely discovered in XenStore after the toolstack created > it. This will allow us to create frontend/backend nodes only when we > should, rather than unconditionally attempting to overwrite them from > a driver domain which doesn't have privileges to do so. > > As an added benefit, it also means we no longer have to call the > xen_backend_set_device() function from the device models immediately > after calling qdev_realize_and_unref(). Even though we could make > the argument that it's safe to do so, and the pointer to the unreffed > device *will* actually still be valid, it still made my skin itch to > look at it. > > Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> > --- > hw/block/xen-block.c | 3 +-- > hw/char/xen_console.c | 2 +- > hw/net/xen_nic.c | 2 +- > hw/xen/xen-bus.c | 4 ++++ > include/hw/xen/xen-backend.h | 2 -- > include/hw/xen/xen-bus.h | 2 ++ > 6 files changed, 9 insertions(+), 6 deletions(-) > Actually, I think you should probably update xen_backend_try_device_destroy() in this patch too. It currently uses xen_backend_list_find() to check whether the specified XenDevice has an associated XenBackendInstance. Paul
Paul Durrant <xadimgnik@gmail.com> writes: > On 21/11/2023 22:10, Volodymyr Babchuk wrote: >> From: David Woodhouse <dwmw@amazon.co.uk> >> This allows a XenDevice implementation to know whether it was >> created >> by QEMU, or merely discovered in XenStore after the toolstack created >> it. This will allow us to create frontend/backend nodes only when we >> should, rather than unconditionally attempting to overwrite them from >> a driver domain which doesn't have privileges to do so. >> As an added benefit, it also means we no longer have to call the >> xen_backend_set_device() function from the device models immediately >> after calling qdev_realize_and_unref(). Even though we could make >> the argument that it's safe to do so, and the pointer to the unreffed >> device *will* actually still be valid, it still made my skin itch to >> look at it. >> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> >> --- >> hw/block/xen-block.c | 3 +-- >> hw/char/xen_console.c | 2 +- >> hw/net/xen_nic.c | 2 +- >> hw/xen/xen-bus.c | 4 ++++ >> include/hw/xen/xen-backend.h | 2 -- >> include/hw/xen/xen-bus.h | 2 ++ >> 6 files changed, 9 insertions(+), 6 deletions(-) >> > > Actually, I think you should probably update > xen_backend_try_device_destroy() in this patch too. It currently uses > xen_backend_list_find() to check whether the specified XenDevice has > an associated XenBackendInstance. Sure. Looks like it is the only user of xen_backend_list_find(), so we can get rid of it as well. I'll drop your R-b tag, because of those additional changes in the new version.
On Wed, 2023-11-22 at 22:56 +0000, Volodymyr Babchuk wrote: > > > Paul Durrant <xadimgnik@gmail.com> writes: > > > On 21/11/2023 22:10, Volodymyr Babchuk wrote: > > > From: David Woodhouse <dwmw@amazon.co.uk> > > > This allows a XenDevice implementation to know whether it was > > > created > > > by QEMU, or merely discovered in XenStore after the toolstack created > > > it. This will allow us to create frontend/backend nodes only when we > > > should, rather than unconditionally attempting to overwrite them from > > > a driver domain which doesn't have privileges to do so. > > > As an added benefit, it also means we no longer have to call the > > > xen_backend_set_device() function from the device models immediately > > > after calling qdev_realize_and_unref(). Even though we could make > > > the argument that it's safe to do so, and the pointer to the unreffed > > > device *will* actually still be valid, it still made my skin itch to > > > look at it. > > > Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> > > > --- > > > hw/block/xen-block.c | 3 +-- > > > hw/char/xen_console.c | 2 +- > > > hw/net/xen_nic.c | 2 +- > > > hw/xen/xen-bus.c | 4 ++++ > > > include/hw/xen/xen-backend.h | 2 -- > > > include/hw/xen/xen-bus.h | 2 ++ > > > 6 files changed, 9 insertions(+), 6 deletions(-) > > > > > > > Actually, I think you should probably update > > xen_backend_try_device_destroy() in this patch too. It currently uses > > xen_backend_list_find() to check whether the specified XenDevice has > > an associated XenBackendInstance. > > Sure. Looks like it is the only user of xen_backend_list_find(), so we > can get rid of it as well. > > I'll drop your R-b tag, because of those additional changes in the new > version. I think it's fine to keep. He told me to do it :)
Hi David, "Woodhouse, David" <dwmw@amazon.co.uk> writes: > On Wed, 2023-11-22 at 17:05 +0000, Paul Durrant wrote: >> On 21/11/2023 22:10, Volodymyr Babchuk wrote: >> > From: David Woodhouse <dwmw@amazon.co.uk> >> > >> > This allows a XenDevice implementation to know whether it was created >> > by QEMU, or merely discovered in XenStore after the toolstack created >> > it. This will allow us to create frontend/backend nodes only when we >> > should, rather than unconditionally attempting to overwrite them from >> > a driver domain which doesn't have privileges to do so. >> > >> > As an added benefit, it also means we no longer have to call the >> > xen_backend_set_device() function from the device models immediately >> > after calling qdev_realize_and_unref(). Even though we could make >> > the argument that it's safe to do so, and the pointer to the unreffed >> > device *will* actually still be valid, it still made my skin itch to >> > look at it. >> > >> > Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> >> > --- >> > hw/block/xen-block.c | 3 +-- >> > hw/char/xen_console.c | 2 +- >> > hw/net/xen_nic.c | 2 +- >> > hw/xen/xen-bus.c | 4 ++++ >> > include/hw/xen/xen-backend.h | 2 -- >> > include/hw/xen/xen-bus.h | 2 ++ >> > 6 files changed, 9 insertions(+), 6 deletions(-) >> > >> >> Actually, I think you should probably update >> xen_backend_try_device_destroy() in this patch too. It currently uses >> xen_backend_list_find() to check whether the specified XenDevice has an >> associated XenBackendInstance. > > I think I did that in > https://git.infradead.org/users/dwmw2/qemu.git/commitdiff/94f1b474478ce0ede > but didn't get round to sending it out again because of travel. I can just pull it from this link, if you don't mind.
On 22/11/2023 23:04, David Woodhouse wrote: > On Wed, 2023-11-22 at 22:56 +0000, Volodymyr Babchuk wrote: >> >> >> Paul Durrant <xadimgnik@gmail.com> writes: >> >>> On 21/11/2023 22:10, Volodymyr Babchuk wrote: >>>> From: David Woodhouse <dwmw@amazon.co.uk> >>>> This allows a XenDevice implementation to know whether it was >>>> created >>>> by QEMU, or merely discovered in XenStore after the toolstack created >>>> it. This will allow us to create frontend/backend nodes only when we >>>> should, rather than unconditionally attempting to overwrite them from >>>> a driver domain which doesn't have privileges to do so. >>>> As an added benefit, it also means we no longer have to call the >>>> xen_backend_set_device() function from the device models immediately >>>> after calling qdev_realize_and_unref(). Even though we could make >>>> the argument that it's safe to do so, and the pointer to the unreffed >>>> device *will* actually still be valid, it still made my skin itch to >>>> look at it. >>>> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> >>>> --- >>>> hw/block/xen-block.c | 3 +-- >>>> hw/char/xen_console.c | 2 +- >>>> hw/net/xen_nic.c | 2 +- >>>> hw/xen/xen-bus.c | 4 ++++ >>>> include/hw/xen/xen-backend.h | 2 -- >>>> include/hw/xen/xen-bus.h | 2 ++ >>>> 6 files changed, 9 insertions(+), 6 deletions(-) >>>> >>> >>> Actually, I think you should probably update >>> xen_backend_try_device_destroy() in this patch too. It currently uses >>> xen_backend_list_find() to check whether the specified XenDevice has >>> an associated XenBackendInstance. >> >> Sure. Looks like it is the only user of xen_backend_list_find(), so we >> can get rid of it as well. >> >> I'll drop your R-b tag, because of those additional changes in the new >> version. > > I think it's fine to keep. He told me to do it :) I confirm that :-)
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c index 6d64ede94f..c2ac9db4a2 100644 --- a/hw/block/xen-block.c +++ b/hw/block/xen-block.c @@ -1081,13 +1081,12 @@ static void xen_block_device_create(XenBackendInstance *backend, blockdev->iothread = iothread; blockdev->drive = drive; + xendev->backend = backend; if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) { error_prepend(errp, "realization of device %s failed: ", type); goto fail; } - - xen_backend_set_device(backend, xendev); return; fail: diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c index 5cbee2f184..bef8a3a621 100644 --- a/hw/char/xen_console.c +++ b/hw/char/xen_console.c @@ -600,8 +600,8 @@ static void xen_console_device_create(XenBackendInstance *backend, goto fail; } + xendev->backend = backend; if (qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) { - xen_backend_set_device(backend, xendev); goto done; } diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c index af4ba3f1e6..afa10c96e8 100644 --- a/hw/net/xen_nic.c +++ b/hw/net/xen_nic.c @@ -627,8 +627,8 @@ static void xen_net_device_create(XenBackendInstance *backend, net->dev = number; memcpy(&net->conf.macaddr, &mac, sizeof(mac)); + xendev->backend = backend; if (qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) { - xen_backend_set_device(backend, xendev); return; } diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index 4973e7d9c9..dd0171ab98 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -1079,6 +1079,10 @@ static void xen_device_realize(DeviceState *dev, Error **errp) } } + if (xendev->backend) { + xen_backend_set_device(xendev->backend, xendev); + } + xendev->exit.notify = xen_device_exit; qemu_add_exit_notifier(&xendev->exit); return; diff --git a/include/hw/xen/xen-backend.h b/include/hw/xen/xen-backend.h index 0f01631ae7..ea080ba7c9 100644 --- a/include/hw/xen/xen-backend.h +++ b/include/hw/xen/xen-backend.h @@ -10,8 +10,6 @@ #include "hw/xen/xen-bus.h" -typedef struct XenBackendInstance XenBackendInstance; - typedef void (*XenBackendDeviceCreate)(XenBackendInstance *backend, QDict *opts, Error **errp); typedef void (*XenBackendDeviceDestroy)(XenBackendInstance *backend, diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h index 334ddd1ff6..7647c4c38e 100644 --- a/include/hw/xen/xen-bus.h +++ b/include/hw/xen/xen-bus.h @@ -14,9 +14,11 @@ #include "qom/object.h" typedef struct XenEventChannel XenEventChannel; +typedef struct XenBackendInstance XenBackendInstance; struct XenDevice { DeviceState qdev; + XenBackendInstance *backend; domid_t frontend_id; char *name; struct qemu_xs_handle *xsh;