From bc8a76a152c5f9ef3b48104154a65a68a8b76946 Mon Sep 17 00:00:00 2001 From: Akeem G Abodunrin Date: Wed, 8 Jan 2020 09:25:00 -0800 Subject: [PATCH] drm/i915/gen9: Clear residual context state on context switch Intel ID: PSIRT-TA-201910-001 CVEID: CVE-2019-14615 Intel GPU Hardware prior to Gen11 does not clear EU state during a context switch. This can result in information leakage between contexts. For Gen8 and Gen9, hardware provides a mechanism for fast cleardown of the EU state, by issuing a PIPE_CONTROL with bit 27 set. We can use this in a context batch buffer to explicitly cleardown the state on every context switch. As this workaround is already in place for gen8, we can borrow the code verbatim for Gen9. Signed-off-by: Mika Kuoppala Signed-off-by: Akeem G Abodunrin Cc: Kumar Valsan Prathap Cc: Chris Wilson Cc: Balestrieri Francesco Cc: Bloomfield Jon Cc: Dutt Sudeep --- drivers/gpu/drm/i915/gt/intel_lrc.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 75dd0e0367b7..f0485784afbe 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -2664,6 +2664,14 @@ static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch) /* WaFlushCoherentL3CacheLinesAtContextSwitch:skl,bxt,glk */ batch = gen8_emit_flush_coherentl3_wa(engine, batch); + /* WaClearSlmSpaceAtContextSwitch:skl,bxt,kbl,glk,cfl */ + batch = gen8_emit_pipe_control(batch, + PIPE_CONTROL_FLUSH_L3 | + PIPE_CONTROL_STORE_DATA_INDEX | + PIPE_CONTROL_CS_STALL | + PIPE_CONTROL_QW_WRITE, + LRC_PPHWSP_SCRATCH_ADDR); + batch = emit_lri(batch, lri, ARRAY_SIZE(lri)); /* WaMediaPoolStateCmdInWABB:bxt,glk */