virt: vbox: Add support for the new VBG_IOCTL_ACQUIRE_GUEST_CAPABILITIES ioctl

Add support for the new VBG_IOCTL_ACQUIRE_GUEST_CAPABILITIES ioctl, this
is necessary for automatic resizing of the guest resolution to match the
VM-window size to work with the new VMSVGA virtual GPU which is now the
new default in VirtualBox.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1789545
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200709120858.63928-6-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/virt/vboxguest/vboxguest_core.c b/drivers/virt/vboxguest/vboxguest_core.c
index 15b3cb6..4f1adda 100644 (file)
--- a/drivers/virt/vboxguest/vboxguest_core.c
+++ b/drivers/virt/vboxguest/vboxguest_core.c
@@ -679,7 +679,7 @@ static int vbg_set_host_capabilities(struct vbg_dev *gdev,
 
        WARN_ON(!mutex_is_locked(&gdev->session_mutex));
 
-       caps = gdev->set_guest_caps_tracker.mask;
+       caps = gdev->acquired_guest_caps | gdev->set_guest_caps_tracker.mask;
 
        if (gdev->guest_caps_host == caps)
                return 0;
@@ -704,6 +704,113 @@ static int vbg_set_host_capabilities(struct vbg_dev *gdev,
 }
 
 /**
+ * Acquire (get exclusive access) guest capabilities for a session.
+ * Takes the session mutex.
+ * Return: 0 or negative errno value.
+ * @gdev:                      The Guest extension device.
+ * @session:                   The session.
+ * @flags:                     Flags (VBGL_IOC_AGC_FLAGS_XXX).
+ * @or_mask:                   The capabilities to add.
+ * @not_mask:                  The capabilities to remove.
+ * @session_termination:       Set if we're called by the session cleanup code.
+ *                             This tweaks the error handling so we perform
+ *                             proper session cleanup even if the host
+ *                             misbehaves.
+ */
+static int vbg_acquire_session_capabilities(struct vbg_dev *gdev,
+                                           struct vbg_session *session,
+                                           u32 or_mask, u32 not_mask,
+                                           u32 flags, bool session_termination)
+{
+       unsigned long irqflags;
+       bool wakeup = false;
+       int ret = 0;
+
+       mutex_lock(&gdev->session_mutex);
+
+       if (gdev->set_guest_caps_tracker.mask & or_mask) {
+               vbg_err("%s error: cannot acquire caps which are currently set\n",
+                       __func__);
+               ret = -EINVAL;
+               goto out;
+       }
+
+       /*
+        * Mark any caps in the or_mask as now being in acquire-mode. Note
+        * once caps are in acquire_mode they always stay in this mode.
+        * This impacts event handling, so we take the event-lock.
+        */
+       spin_lock_irqsave(&gdev->event_spinlock, irqflags);
+       gdev->acquire_mode_guest_caps |= or_mask;
+       spin_unlock_irqrestore(&gdev->event_spinlock, irqflags);
+
+       /* If we only have to switch the caps to acquire mode, we're done. */
+       if (flags & VBGL_IOC_AGC_FLAGS_CONFIG_ACQUIRE_MODE)
+               goto out;
+
+       not_mask &= ~or_mask; /* or_mask takes priority over not_mask */
+       not_mask &= session->acquired_guest_caps;
+       or_mask &= ~session->acquired_guest_caps;
+
+       if (or_mask == 0 && not_mask == 0)
+               goto out;
+
+       if (gdev->acquired_guest_caps & or_mask) {
+               ret = -EBUSY;
+               goto out;
+       }
+
+       gdev->acquired_guest_caps |= or_mask;
+       gdev->acquired_guest_caps &= ~not_mask;
+       /* session->acquired_guest_caps impacts event handling, take the lock */
+       spin_lock_irqsave(&gdev->event_spinlock, irqflags);
+       session->acquired_guest_caps |= or_mask;
+       session->acquired_guest_caps &= ~not_mask;
+       spin_unlock_irqrestore(&gdev->event_spinlock, irqflags);
+
+       ret = vbg_set_host_capabilities(gdev, session, session_termination);
+       /* Roll back on failure, unless it's session termination time. */
+       if (ret < 0 && !session_termination) {
+               gdev->acquired_guest_caps &= ~or_mask;
+               gdev->acquired_guest_caps |= not_mask;
+               spin_lock_irqsave(&gdev->event_spinlock, irqflags);
+               session->acquired_guest_caps &= ~or_mask;
+               session->acquired_guest_caps |= not_mask;
+               spin_unlock_irqrestore(&gdev->event_spinlock, irqflags);
+       }
+
+       /*
+        * If we added a capability, check if that means some other thread in
+        * our session should be unblocked because there are events pending
+        * (the result of vbg_get_allowed_event_mask_for_session() may change).
+        *
+        * HACK ALERT! When the seamless support capability is added we generate
+        *      a seamless change event so that the ring-3 client can sync with
+        *      the seamless state.
+        */
+       if (ret == 0 && or_mask != 0) {
+               spin_lock_irqsave(&gdev->event_spinlock, irqflags);
+
+               if (or_mask & VMMDEV_GUEST_SUPPORTS_SEAMLESS)
+                       gdev->pending_events |=
+                               VMMDEV_EVENT_SEAMLESS_MODE_CHANGE_REQUEST;
+
+               if (gdev->pending_events)
+                       wakeup = true;
+
+               spin_unlock_irqrestore(&gdev->event_spinlock, irqflags);
+
+               if (wakeup)
+                       wake_up(&gdev->event_wq);
+       }
+
+out:
+       mutex_unlock(&gdev->session_mutex);
+
+       return ret;
+}
+
+/**
  * Sets the guest capabilities for a session. Takes the session spinlock.
  * Return: 0 or negative errno value.
  * @gdev:                      The Guest extension device.
@@ -725,6 +832,13 @@ static int vbg_set_session_capabilities(struct vbg_dev *gdev,
 
        mutex_lock(&gdev->session_mutex);
 
+       if (gdev->acquire_mode_guest_caps & or_mask) {
+               vbg_err("%s error: cannot set caps which are in acquire_mode\n",
+                       __func__);
+               ret = -EBUSY;
+               goto out;
+       }
+
        /* Apply the changes to the session mask. */
        previous = session->set_guest_caps;
        session->set_guest_caps |= or_mask;
@@ -962,6 +1076,7 @@ void vbg_core_close_session(struct vbg_session *session)
        struct vbg_dev *gdev = session->gdev;
        int i, rc;
 
+       vbg_acquire_session_capabilities(gdev, session, 0, U32_MAX, 0, true);
        vbg_set_session_capabilities(gdev, session, 0, U32_MAX, true);
        vbg_set_session_event_filter(gdev, session, 0, U32_MAX, true);
 
@@ -1019,6 +1134,25 @@ static int vbg_ioctl_driver_version_info(
        return 0;
 }
 
+/* Must be called with the event_lock held */
+static u32 vbg_get_allowed_event_mask_for_session(struct vbg_dev *gdev,
+                                                 struct vbg_session *session)
+{
+       u32 acquire_mode_caps = gdev->acquire_mode_guest_caps;
+       u32 session_acquired_caps = session->acquired_guest_caps;
+       u32 allowed_events = VMMDEV_EVENT_VALID_EVENT_MASK;
+
+       if ((acquire_mode_caps & VMMDEV_GUEST_SUPPORTS_GRAPHICS) &&
+           !(session_acquired_caps & VMMDEV_GUEST_SUPPORTS_GRAPHICS))
+               allowed_events &= ~VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST;
+
+       if ((acquire_mode_caps & VMMDEV_GUEST_SUPPORTS_SEAMLESS) &&
+           !(session_acquired_caps & VMMDEV_GUEST_SUPPORTS_SEAMLESS))
+               allowed_events &= ~VMMDEV_EVENT_SEAMLESS_MODE_CHANGE_REQUEST;
+
+       return allowed_events;
+}
+
 static bool vbg_wait_event_cond(struct vbg_dev *gdev,
                                struct vbg_session *session,
                                u32 event_mask)
@@ -1030,6 +1164,7 @@ static bool vbg_wait_event_cond(struct vbg_dev *gdev,
        spin_lock_irqsave(&gdev->event_spinlock, flags);
 
        events = gdev->pending_events & event_mask;
+       events &= vbg_get_allowed_event_mask_for_session(gdev, session);
        wakeup = events || session->cancel_waiters;
 
        spin_unlock_irqrestore(&gdev->event_spinlock, flags);
@@ -1044,6 +1179,7 @@ static u32 vbg_consume_events_locked(struct vbg_dev *gdev,
 {
        u32 events = gdev->pending_events & event_mask;
 
+       events &= vbg_get_allowed_event_mask_for_session(gdev, session);
        gdev->pending_events &= ~events;
        return events;
 }
@@ -1445,6 +1581,29 @@ static int vbg_ioctl_change_filter_mask(struct vbg_dev *gdev,
                                            false);
 }
 
+static int vbg_ioctl_acquire_guest_capabilities(struct vbg_dev *gdev,
+            struct vbg_session *session,
+            struct vbg_ioctl_acquire_guest_caps *caps)
+{
+       u32 flags, or_mask, not_mask;
+
+       if (vbg_ioctl_chk(&caps->hdr, sizeof(caps->u.in), 0))
+               return -EINVAL;
+
+       flags = caps->u.in.flags;
+       or_mask = caps->u.in.or_mask;
+       not_mask = caps->u.in.not_mask;
+
+       if (flags & ~VBGL_IOC_AGC_FLAGS_VALID_MASK)
+               return -EINVAL;
+
+       if ((or_mask | not_mask) & ~VMMDEV_GUEST_CAPABILITIES_MASK)
+               return -EINVAL;
+
+       return vbg_acquire_session_capabilities(gdev, session, or_mask,
+                                               not_mask, flags, false);
+}
+
 static int vbg_ioctl_change_guest_capabilities(struct vbg_dev *gdev,
             struct vbg_session *session, struct vbg_ioctl_set_guest_caps *caps)
 {
@@ -1554,6 +1713,8 @@ int vbg_core_ioctl(struct vbg_session *session, unsigned int req, void *data)
                return vbg_ioctl_interrupt_all_wait_events(gdev, session, data);
        case VBG_IOCTL_CHANGE_FILTER_MASK:
                return vbg_ioctl_change_filter_mask(gdev, session, data);
+       case VBG_IOCTL_ACQUIRE_GUEST_CAPABILITIES:
+               return vbg_ioctl_acquire_guest_capabilities(gdev, session, data);
        case VBG_IOCTL_CHANGE_GUEST_CAPABILITIES:
                return vbg_ioctl_change_guest_capabilities(gdev, session, data);
        case VBG_IOCTL_CHECK_BALLOON:

diff --git a/drivers/virt/vboxguest/vboxguest_core.h b/drivers/virt/vboxguest/vboxguest_core.h
index dc745a0..ab4bf64 100644 (file)
--- a/drivers/virt/vboxguest/vboxguest_core.h
+++ b/drivers/virt/vboxguest/vboxguest_core.h
@@ -118,6 +118,15 @@ struct vbg_dev {
        u32 event_filter_host;
 
        /**
+        * Guest capabilities which have been switched to acquire_mode.
+        */
+       u32 acquire_mode_guest_caps;
+       /**
+        * Guest capabilities acquired by vbg_acquire_session_capabilities().
+        * Only one session can acquire a capability at a time.
+        */
+       u32 acquired_guest_caps;
+       /**
         * Usage counters for guest capabilities requested through
         * vbg_set_session_capabilities(). Indexed by capability bit
         * number, one count per session using a capability.
@@ -165,6 +174,11 @@ struct vbg_session {
         */
        u32 event_filter;
        /**
+        * Guest capabilities acquired by vbg_acquire_session_capabilities().
+        * Only one session can acquire a capability at a time.
+        */
+       u32 acquired_guest_caps;
+       /**
         * Guest capabilities set through vbg_set_session_capabilities().
         * A capability claimed by any guest session will be reported to the
         * host. Protected by vbg_gdev.session_mutex.

diff --git a/include/uapi/linux/vboxguest.h b/include/uapi/linux/vboxguest.h
index f79d7ab..15125f6 100644 (file)
--- a/include/uapi/linux/vboxguest.h
+++ b/include/uapi/linux/vboxguest.h
@@ -257,6 +257,30 @@ VMMDEV_ASSERT_SIZE(vbg_ioctl_change_filter, 24 + 8);
        _IOWR('V', 12, struct vbg_ioctl_change_filter)
 
 
+/** VBG_IOCTL_ACQUIRE_GUEST_CAPABILITIES data structure. */
+struct vbg_ioctl_acquire_guest_caps {
+       /** The header. */
+       struct vbg_ioctl_hdr hdr;
+       union {
+               struct {
+                       /** Flags (VBGL_IOC_AGC_FLAGS_XXX). */
+                       __u32 flags;
+                       /** Capabilities to set (VMMDEV_GUEST_SUPPORTS_XXX). */
+                       __u32 or_mask;
+                       /** Capabilities to drop (VMMDEV_GUEST_SUPPORTS_XXX). */
+                       __u32 not_mask;
+               } in;
+       } u;
+};
+VMMDEV_ASSERT_SIZE(vbg_ioctl_acquire_guest_caps, 24 + 12);
+
+#define VBGL_IOC_AGC_FLAGS_CONFIG_ACQUIRE_MODE         0x00000001
+#define VBGL_IOC_AGC_FLAGS_VALID_MASK                  0x00000001
+
+#define VBG_IOCTL_ACQUIRE_GUEST_CAPABILITIES \
+       _IOWR('V', 13, struct vbg_ioctl_acquire_guest_caps)
+
+
 /** VBG_IOCTL_CHANGE_GUEST_CAPABILITIES data structure. */
 struct vbg_ioctl_set_guest_caps {
        /** The header. */