On Mon, Feb 19, 2024 at 11:45 AM Albert Esteve <aest...@redhat.com> wrote:
>
>
>
> On Thu, Feb 15, 2024 at 10:45 AM Albert Esteve <aest...@redhat.com> wrote:
>
>>
>>
>> On Tue, Feb 6, 2024 at 12:11 AM Alex Bennée <alex.ben...@linaro.org>
>> wrote:
>>
>>> Albert Esteve <aest...@redhat.com> writes:
>>>
>>> > Ensure that we cleanup all virtio shared
>>> > resources when the vhost devices is cleaned
>>> > up (after a hot unplug, or a crash).
>>> >
>>> > To do so, we add a new function to the virtio_dmabuf
>>> > API called `virtio_dmabuf_vhost_cleanup`, which
>>> > loop through the table and removes all
>>> > resources owned by the vhost device parameter.
>>> >
>>> > Also, add a test to verify that the new
>>> > function in the API behaves as expected.
>>> >
>>> > Signed-off-by: Albert Esteve <aest...@redhat.com>
>>> > Acked-by: Stefan Hajnoczi <stefa...@redhat.com>
>>> > ---
>>> > hw/display/virtio-dmabuf.c | 22 +++++++++++++++++++++
>>> > hw/virtio/vhost.c | 3 +++
>>> > include/hw/virtio/virtio-dmabuf.h | 10 ++++++++++
>>> > tests/unit/test-virtio-dmabuf.c | 33 +++++++++++++++++++++++++++++++
>>> > 4 files changed, 68 insertions(+)
>>> >
>>> > diff --git a/hw/display/virtio-dmabuf.c b/hw/display/virtio-dmabuf.c
>>> > index 3dba4577ca..6688809777 100644
>>> > --- a/hw/display/virtio-dmabuf.c
>>> > +++ b/hw/display/virtio-dmabuf.c
>>> > @@ -136,6 +136,28 @@ SharedObjectType virtio_object_type(const
>>> QemuUUID *uuid)
>>> > return vso->type;
>>> > }
>>> >
>>> > +static bool virtio_dmabuf_resource_is_owned(gpointer key,
>>> > + gpointer value,
>>> > + gpointer dev)
>>> > +{
>>> > + VirtioSharedObject *vso;
>>> > +
>>> > + vso = (VirtioSharedObject *) value;
>>> > + return vso->type == TYPE_VHOST_DEV && vso->value == dev;
>>>
>>> It's a bit surprising to see vso->value being an anonymous gpointer
>>> rather than the proper type and a bit confusing between value and
>>> vso->value.
>>>
>>>
>> It is the signature required for this to be used with
>> `g_hash_table_foreach_remove`.
>> For the naming, the HashMap stores gpointers, that point to
>> `VirtioSharedObject`, and
>> these point to the underlying type (stored at `vso->value`). It may sound
>> a bit confusing,
>> but is a byproduct of the VirtioSharedObject indirection. Not sure which
>> names could be
>> more fit for this, but I'm open to change them.
>>
>>
>>> > +}
>>> > +
>>> > +int virtio_dmabuf_vhost_cleanup(struct vhost_dev *dev)
>>> > +{
>>> > + int num_removed;
>>> > +
>>> > + g_mutex_lock(&lock);
>>> > + num_removed = g_hash_table_foreach_remove(
>>> > + resource_uuids, (GHRFunc) virtio_dmabuf_resource_is_owned,
>>> dev);
>>> > + g_mutex_unlock(&lock);
>>>
>>> I'll note if we used a QemuMutex for the lock we could:
>>>
>>> - use WITH_QEMU_LOCK_GUARD(&lock) { }
>>> - enable QSP porfiling for the lock
>>>
>>>
>> Was not aware of these QemuMutex's. I wouldn't mind changing the mutex in
>> this
>> file in a different commit.
>>
>
> The problem is that current lock is a global static, and `QemuMutex` needs
> to be
> initialised by doing `qemu_mutex_init(&lock);`.
>
> Maybe can be initialised at vhost-user.c by adding a public function?
>
I think `virtio_init` at `virtio.c` will be a better candidate.
>
>
>>
>>
>>> > +
>>> > + return num_removed;
>>> > +}
>>> > +
>>> > void virtio_free_resources(void)
>>> > {
>>> > g_mutex_lock(&lock);
>>> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>>> > index 2c9ac79468..c5622eac14 100644
>>> > --- a/hw/virtio/vhost.c
>>> > +++ b/hw/virtio/vhost.c
>>> > @@ -16,6 +16,7 @@
>>> > #include "qemu/osdep.h"
>>> > #include "qapi/error.h"
>>> > #include "hw/virtio/vhost.h"
>>> > +#include "hw/virtio/virtio-dmabuf.h"
>>> > #include "qemu/atomic.h"
>>> > #include "qemu/range.h"
>>> > #include "qemu/error-report.h"
>>> > @@ -1599,6 +1600,8 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
>>> > migrate_del_blocker(&hdev->migration_blocker);
>>> > g_free(hdev->mem);
>>> > g_free(hdev->mem_sections);
>>> > + /* free virtio shared objects */
>>> > + virtio_dmabuf_vhost_cleanup(hdev);
>>> > if (hdev->vhost_ops) {
>>> > hdev->vhost_ops->vhost_backend_cleanup(hdev);
>>> > }
>>> > diff --git a/include/hw/virtio/virtio-dmabuf.h
>>> b/include/hw/virtio/virtio-dmabuf.h
>>> > index 627c3b6db7..73f70fb482 100644
>>> > --- a/include/hw/virtio/virtio-dmabuf.h
>>> > +++ b/include/hw/virtio/virtio-dmabuf.h
>>> > @@ -91,6 +91,16 @@ struct vhost_dev *virtio_lookup_vhost_device(const
>>> QemuUUID *uuid);
>>> > */
>>> > SharedObjectType virtio_object_type(const QemuUUID *uuid);
>>> >
>>> > +/**
>>> > + * virtio_dmabuf_vhost_cleanup() - Destroys all entries of the shared
>>> > + * resources lookup table that are owned by the vhost backend
>>> > + * @dev: the pointer to the vhost device that owns the entries. Data
>>> is owned
>>> > + * by the called of the function.
>>> > + *
>>> > + * Return: the number of resource entries removed.
>>> > + */
>>> > +int virtio_dmabuf_vhost_cleanup(struct vhost_dev *dev);
>>> > +
>>> > /**
>>> > * virtio_free_resources() - Destroys all keys and values of the
>>> shared
>>> > * resources lookup table, and frees them
>>> > diff --git a/tests/unit/test-virtio-dmabuf.c
>>> b/tests/unit/test-virtio-dmabuf.c
>>> > index a45ec52f42..1c8123c2d2 100644
>>> > --- a/tests/unit/test-virtio-dmabuf.c
>>> > +++ b/tests/unit/test-virtio-dmabuf.c
>>> > @@ -103,6 +103,38 @@ static void test_add_invalid_resource(void)
>>> > }
>>> > }
>>> >
>>> > +static void test_cleanup_res(void)
>>> > +{
>>> > + QemuUUID uuids[20], uuid_alt;
>>> > + struct vhost_dev *dev = g_new0(struct vhost_dev, 1);
>>> > + struct vhost_dev *dev_alt = g_new0(struct vhost_dev, 1);
>>> > + int i, num_removed;
>>> > +
>>> > + for (i = 0; i < ARRAY_SIZE(uuids); ++i) {
>>> > + qemu_uuid_generate(&uuids[i]);
>>> > + virtio_add_vhost_device(&uuids[i], dev);
>>> > + /* vhost device is found */
>>> > + g_assert(virtio_lookup_vhost_device(&uuids[i]) != NULL);
>>> > + }
>>> > + qemu_uuid_generate(&uuid_alt);
>>> > + virtio_add_vhost_device(&uuid_alt, dev_alt);
>>> > + /* vhost device is found */
>>> > + g_assert(virtio_lookup_vhost_device(&uuid_alt) != NULL);
>>> > + /* cleanup all dev resources */
>>> > + num_removed = virtio_dmabuf_vhost_cleanup(dev);
>>> > + g_assert_cmpint(num_removed, ==, ARRAY_SIZE(uuids));
>>> > + for (i = 0; i < ARRAY_SIZE(uuids); ++i) {
>>> > + /* None of the dev resources is found after free'd */
>>> > + g_assert_cmpint(virtio_lookup_dmabuf(&uuids[i]), ==, -1);
>>> > + }
>>> > + /* uuid_alt is still in the hash table */
>>> > + g_assert(virtio_lookup_vhost_device(&uuid_alt) != NULL);
>>> > +
>>> > + virtio_free_resources();
>>> > + g_free(dev);
>>> > + g_free(dev_alt);
>>> > +}
>>> > +
>>> > static void test_free_resources(void)
>>> > {
>>> > QemuUUID uuids[20];
>>> > @@ -131,6 +163,7 @@ int main(int argc, char **argv)
>>> > test_remove_invalid_resource);
>>> > g_test_add_func("/virtio-dmabuf/add_invalid_res",
>>> > test_add_invalid_resource);
>>> > + g_test_add_func("/virtio-dmabuf/cleanup_dev", test_cleanup_res);
>>> > g_test_add_func("/virtio-dmabuf/free_res", test_free_resources);
>>> >
>>> > return g_test_run();
>>>
>>> --
>>> Alex Bennée
>>> Virtualisation Tech Lead @ Linaro
>>>
>>>
