virt: vbox: Add vbg_set_host_capabilities() helper function

Add vbg_set_host_capabilities() helper function,  this is a preparation
patch for adding support for the VBGL_IOCTL_GUEST_CAPS_ACQUIRE ioctl.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200709120858.63928-5-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 aee5eff..15b3cb6 100644 (file)
--- a/drivers/virt/vboxguest/vboxguest_core.c
+++ b/drivers/virt/vboxguest/vboxguest_core.c
@@ -661,6 +661,48 @@ static int vbg_reset_host_capabilities(struct vbg_dev *gdev)
        return vbg_status_code_to_errno(rc);
 }
 
+/**
+ * Set guest capabilities on the host.
+ * Must be called with gdev->session_mutex hold.
+ * Return: 0 or negative errno value.
+ * @gdev:                      The Guest extension device.
+ * @session:                   The session.
+ * @session_termination:       Set if we're called by the session cleanup code.
+ */
+static int vbg_set_host_capabilities(struct vbg_dev *gdev,
+                                    struct vbg_session *session,
+                                    bool session_termination)
+{
+       struct vmmdev_mask *req;
+       u32 caps;
+       int rc;
+
+       WARN_ON(!mutex_is_locked(&gdev->session_mutex));
+
+       caps = gdev->set_guest_caps_tracker.mask;
+
+       if (gdev->guest_caps_host == caps)
+               return 0;
+
+       /* On termination the requestor is the kernel, as we're cleaning up. */
+       req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_GUEST_CAPABILITIES,
+                           session_termination ? VBG_KERNEL_REQUEST :
+                                                 session->requestor);
+       if (!req) {
+               gdev->guest_caps_host = U32_MAX;
+               return -ENOMEM;
+       }
+
+       req->or_mask = caps;
+       req->not_mask = ~caps;
+       rc = vbg_req_perform(gdev, req);
+       vbg_req_free(req, sizeof(*req));
+
+       gdev->guest_caps_host = (rc >= 0) ? caps : U32_MAX;
+
+       return vbg_status_code_to_errno(rc);
+}
+
 /**
  * Sets the guest capabilities for a session. Takes the session spinlock.
  * Return: 0 or negative errno value.
@@ -678,23 +720,8 @@ static int vbg_set_session_capabilities(struct vbg_dev *gdev,
                                        u32 or_mask, u32 not_mask,
                                        bool session_termination)
 {
-       struct vmmdev_mask *req;
        u32 changed, previous;
-       int rc, ret = 0;
-
-       /*
-        * Allocate a request buffer before taking the spinlock, when
-        * the session is being terminated the requestor is the kernel,
-        * as we're cleaning up.
-        */
-       req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_GUEST_CAPABILITIES,
-                           session_termination ? VBG_KERNEL_REQUEST :
-                                                 session->requestor);
-       if (!req) {
-               if (!session_termination)
-                       return -ENOMEM;
-               /* Ignore allocation failure, we must do session cleanup. */
-       }
+       int ret = 0;
 
        mutex_lock(&gdev->session_mutex);
 
@@ -709,23 +736,10 @@ static int vbg_set_session_capabilities(struct vbg_dev *gdev,
                goto out;
 
        vbg_track_bit_usage(&gdev->set_guest_caps_tracker, changed, previous);
-       or_mask = gdev->set_guest_caps_tracker.mask;
-
-       if (gdev->guest_caps_host == or_mask || !req)
-               goto out;
-
-       gdev->guest_caps_host = or_mask;
-       req->or_mask = or_mask;
-       req->not_mask = ~or_mask;
-       rc = vbg_req_perform(gdev, req);
-       if (rc < 0) {
-               ret = vbg_status_code_to_errno(rc);
-
-               /* Failed, roll back (unless it's session termination time). */
-               gdev->guest_caps_host = U32_MAX;
-               if (session_termination)
-                       goto out;
 
+       ret = vbg_set_host_capabilities(gdev, session, session_termination);
+       /* Roll back on failure, unless it's session termination time. */
+       if (ret < 0 && !session_termination) {
                vbg_track_bit_usage(&gdev->set_guest_caps_tracker, changed,
                                    session->set_guest_caps);
                session->set_guest_caps = previous;
@@ -733,7 +747,6 @@ static int vbg_set_session_capabilities(struct vbg_dev *gdev,
 
 out:
        mutex_unlock(&gdev->session_mutex);
-       vbg_req_free(req, sizeof(*req));
 
        return ret;
 }