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Commit 88c0dead authored by Alex Williamson's avatar Alex Williamson
Browse files

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: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 0ea18b40

drivers/vfio/pci/vfio_pci.c

+16 −3
Original line number Diff line number Diff line
@@ -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;

}