[v2] drm/i915: check ppgtt validity when init reg state
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Message ID 20170109131453.3943-1-zhenyuw@linux.intel.com
State New
Headers show

Commit Message

Zhenyu Wang Jan. 9, 2017, 1:14 p.m. UTC
Check if ppgtt is valid for context when init reg state. For gvt
context which has no i915 allocated ppgtt, failed to check that
would cause kernel null ptr reference error.

v2: remove !48bit ppgtt case as we'll always update before submit (Chris)

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

Comments

Chris Wilson Jan. 9, 2017, 1:22 p.m. UTC | #1
On Mon, Jan 09, 2017 at 09:14:53PM +0800, Zhenyu Wang wrote:
> Check if ppgtt is valid for context when init reg state. For gvt
> context which has no i915 allocated ppgtt, failed to check that
> would cause kernel null ptr reference error.
> 
> v2: remove !48bit ppgtt case as we'll always update before submit (Chris)
> 
> Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

In the absence of any ppgtt, the reg state is zeroed (and before any use
by hw in !48bit). That seems reasonable,

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

Patch
diff mbox

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6db246ad2f13..37fc9d4e876a 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2103,19 +2103,12 @@  static void execlists_init_reg_state(u32 *reg_state,
 	ASSIGN_CTX_REG(reg_state, CTX_PDP0_LDW, GEN8_RING_PDP_LDW(engine, 0),
 		       0);
 
-	if (USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
+	if (ppgtt && USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
 		/* 64b PPGTT (48bit canonical)
 		 * PDP0_DESCRIPTOR contains the base address to PML4 and
 		 * other PDP Descriptors are ignored.
 		 */
 		ASSIGN_CTX_PML4(ppgtt, reg_state);
-	} else {
-		/* 32b PPGTT
-		 * PDP*_DESCRIPTOR contains the base address of space supported.
-		 * With dynamic page allocation, PDPs may not be allocated at
-		 * this point. Point the unallocated PDPs to the scratch page
-		 */
-		execlists_update_context_pdps(ppgtt, reg_state);
 	}
 
 	if (engine->id == RCS) {