From 88c0dead9fb2cc66962b64064770558eecf3eafd Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Tue, 7 Apr 2015 11:14:40 -0600 Subject: [PATCH] vfio-pci: Add module option to disable VGA region access Add a module option so that we don't require a CONFIG change and kernel rebuild to disable VGA support. Not only can VGA support be troublesome in itself, but by disabling it we can reduce the impact to host devices by doing a VGA arbitration opt-out. Signed-off-by: Alex Williamson --- drivers/vfio/pci/vfio_pci.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 2f865d07df90..7053110e4734 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -37,8 +37,23 @@ module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(nointxmask, "Disable support for PCI 2.3 style INTx masking. If this resolves problems for specific devices, report lspci -vvvxxx to linux-pci@vger.kernel.org so the device can be fixed automatically via the broken_intx_masking flag."); +#ifdef CONFIG_VFIO_PCI_VGA +static bool disable_vga; +module_param(disable_vga, bool, S_IRUGO); +MODULE_PARM_DESC(disable_vga, "Disable VGA resource access through vfio-pci"); +#endif + static DEFINE_MUTEX(driver_lock); +static inline bool vfio_vga_disabled(void) +{ +#ifdef CONFIG_VFIO_PCI_VGA + return disable_vga; +#else + return true; +#endif +} + static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev); static int vfio_pci_enable(struct vfio_pci_device *vdev) @@ -93,10 +108,8 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) } else vdev->msix_bar = 0xFF; -#ifdef CONFIG_VFIO_PCI_VGA - if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) + if (!vfio_vga_disabled() && (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) vdev->has_vga = true; -#endif return 0; }