From 2d93f960dc7e05c54bc5d3d7edcc0f4ee57e7006 Mon Sep 17 00:00:00 2001 From: Zack Rusin Date: Fri, 5 Nov 2021 15:38:44 -0400 Subject: [PATCH] drm/vmwgfx: Fail to initialize on broken configs [ Upstream commit c451af78f301ff5156998d571c37cab329c10051 ] Some of our hosts have a bug where rescaning a pci bus results in stale fifo memory being mapped on the host. This makes any fifo communication impossible resulting in various kernel crashes. Instead of unexpectedly crashing, predictably fail to load the driver which will preserve the system. Fixes: fb1d9738ca05 ("drm/vmwgfx: Add DRM driver for VMware Virtual GPU") Signed-off-by: Zack Rusin Reviewed-by: Martin Krastev Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-4-zackr@vmware.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c index 67db472d3493c..a3bfbb6c3e14a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c @@ -145,6 +145,13 @@ struct vmw_fifo_state *vmw_fifo_create(struct vmw_private *dev_priv) (unsigned int) max, (unsigned int) min, (unsigned int) fifo->capabilities); + + if (unlikely(min >= max)) { + drm_warn(&dev_priv->drm, + "FIFO memory is not usable. Driver failed to initialize."); + return ERR_PTR(-ENXIO); + } + return fifo; } -- 2.30.2