drm/nouveau/svm: fail NOUVEAU_SVM_INIT ioctl on unsupported devices

BugLink: https://bugs.launchpad.net/bugs/1916056
commit dcd602cc5fe2803bf532d407cde24ba0b7808ff3 upstream.

Fixes a crash when trying to create a channel on e.g. Turing GPUs when
NOUVEAU_SVM_INIT was called before.

Fixes: eeaf06ac1a558 ("drm/nouveau/svm: initial support for shared virtual memory")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 0be4668c780bf6086678baaa4f3e73be39afa388..8556804e96efd13644d2742029f5b027d498ae63 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -306,6 +306,10 @@ nouveau_svmm_init(struct drm_device *dev, void *data,
        struct drm_nouveau_svm_init *args = data;
        int ret;
 
+       /* We need to fail if svm is disabled */
+       if (!cli->drm->svm)
+               return -ENOSYS;
+
        /* Allocate tracking for SVM-enabled VMM. */
        if (!(svmm = kzalloc(sizeof(*svmm), GFP_KERNEL)))
                return -ENOMEM;