From fb8bf0a8513e09b22054e8d9020b9a79a2fce1fc Mon Sep 17 00:00:00 2001 From: Zhenyu Wang Date: Wed, 6 May 2020 17:59:18 +0800 Subject: [PATCH] drm/i915/gvt: Fix kernel oops for 3-level ppgtt guest As i915 won't allocate extra PDP for current default PML4 table, so for 3-level ppgtt guest, we would hit kernel pointer access failure on extra PDP pointers. So this trys to bypass that now. It won't impact real shadow PPGTT setup, so guest context still works. This is verified on 4.15 guest kernel with i915.enable_ppgtt=1 to force on old aliasing ppgtt behavior. Fixes: a161183cd554 ("drm/i915: Add ppgtt to GVT GEM context") Reviewed-by: Xiong Zhang Signed-off-by: Zhenyu Wang Link: http://patchwork.freedesktop.org/patch/msgid/20200506095918.124913-1-zhenyuw@linux.intel.com --- drivers/gpu/drm/i915/gvt/scheduler.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c index cb11c31840857..0f1d6998cf9ce 100644 --- a/drivers/gpu/drm/i915/gvt/scheduler.c +++ b/drivers/gpu/drm/i915/gvt/scheduler.c @@ -379,7 +379,11 @@ static void set_context_ppgtt_from_shadow(struct intel_vgpu_workload *workload, for (i = 0; i < GVT_RING_CTX_NR_PDPS; i++) { struct i915_page_directory * const pd = i915_pd_entry(ppgtt->pd, i); - + /* skip now as current i915 ppgtt alloc won't allocate + top level pdp for non 4-level table, won't impact + shadow ppgtt. */ + if (!pd) + break; px_dma(pd) = mm->ppgtt_mm.shadow_pdps[i]; } } -- 2.39.5