[Intel-gfx] [PATCH 10/10] drm/i915: Disable use of stolen area by User when Intel RST is present

[Chris Wilson]

On Tue, Dec 22, 2015 at 11:50:53AM +0530, ankitprasad.r.sharma at intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> 
> The BIOS RapidStartTechnology may corrupt the stolen memory across S3
> suspend due to unalarmed hibernation, in which case we will not be able
> to preserve the User data stored in the stolen region. Hence this patch
> tries to identify presence of the RST device on the ACPI bus, and
> disables use of stolen memory (for persistent data) if found.
> 
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h        |  7 +++++++
>  drivers/gpu/drm/i915/i915_gem.c        |  8 ++++++++
>  drivers/gpu/drm/i915/i915_gem_stolen.c | 14 ++++++++++++++
>  drivers/gpu/drm/i915/intel_acpi.c      | 20 ++++++++++++++++++++
>  4 files changed, 49 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 492878a..d26a8f1 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1309,6 +1309,9 @@ struct i915_gem_mm {
>  	 */
>  	bool busy;
>  
> +	/* Intel RapidStart Technology info */

This defeats the purpose of using a generic term.

/** Stolen will be lost upon hibernate (as the memory is unpowered).
 * Across resume, we expect stolen to be intact - however, it may
 * also be utililised by third parties (e.g. Intel RapidStart
 * Technology) and if so we hae to assume that any data stored in
 * stolen across resume is lost and we set this flag to indicate that
 * the stolen memory is volatile.
 */
> +	bool nonvolatile_stolen;
> +
>  	/* the indicator for dispatch video commands on two BSD rings */
>  	int bsd_ring_dispatch_index;
>  
> @@ -3417,9 +3420,13 @@ intel_opregion_notify_adapter(struct drm_device *dev, pci_power_t state)
>  #ifdef CONFIG_ACPI
>  extern void intel_register_dsm_handler(void);
>  extern void intel_unregister_dsm_handler(void);
> +extern bool intel_detect_acpi_rst(void);
> +extern int match_device(struct device *dev, void* ids);

As Tvrtko mentioned this is private to the driver.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre