drm/i915/gvt: Support PPGTT table load command

The PPGTT in context image can be overridden by LRI cmd with another
PPGTT's pdps. In such case, the load mm is used instead of the one in
the context image. So we need to load its shadow mm in GVT and replace
ppgtt pointers in command.

This feature is used by guest IGD driver to share gfx VM between
different contexts. Verified by IGT "gem_ctx_clone" test.

v4:
- consolidate shadow mm handlers (Yan)
- fix cmd shadow mm pin error path

v3: (Zhenyu Wang)
- Cleanup PDP register offset check
- Add debug check for guest context ppgtt update
- Skip 3-level ppgtt guest handling code. The reason is that all
  guests now use 4-level ppgtt table and the only left case for
  3-level table is ancient aliasing ppgtt case. But those guest
  kernel has no use of PPGTT LRI command. So 3-level ppgtt guest
  for this feature becomes simply un-testable.

v2: (Zhenyu Wang)
- Change to list for handling possible multiple ppgtt table loads
  in one submission. Make sure shadow mm is to replace for each one.

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200508031409.2562-1-zhenyuw@linux.intel.com

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index 9e065ad0658f..956e5a9fd11b 100644
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -881,6 +881,47 @@ static int mocs_cmd_reg_handler(struct parser_exec_state *s,
 	return 0;
 }
 
+static int is_cmd_update_pdps(unsigned int offset,
+			      struct parser_exec_state *s)
+{
+	u32 base = s->workload->engine->mmio_base;
+	return i915_mmio_reg_equal(_MMIO(offset), GEN8_RING_PDP_UDW(base, 0));
+}
+
+static int cmd_pdp_mmio_update_handler(struct parser_exec_state *s,
+				       unsigned int offset, unsigned int index)
+{
+	struct intel_vgpu *vgpu = s->vgpu;
+	struct intel_vgpu_mm *shadow_mm = s->workload->shadow_mm;
+	struct intel_vgpu_mm *mm;
+	u64 pdps[GEN8_3LVL_PDPES];
+
+	if (shadow_mm->ppgtt_mm.root_entry_type ==
+	    GTT_TYPE_PPGTT_ROOT_L4_ENTRY) {
+		pdps[0] = (u64)cmd_val(s, 2) << 32;
+		pdps[0] |= cmd_val(s, 4);
+
+		mm = intel_vgpu_find_ppgtt_mm(vgpu, pdps);
+		if (!mm) {
+			gvt_vgpu_err("failed to get the 4-level shadow vm\n");
+			return -EINVAL;
+		}
+		intel_vgpu_mm_get(mm);
+		list_add_tail(&mm->ppgtt_mm.link,
+			      &s->workload->lri_shadow_mm);
+		*cmd_ptr(s, 2) = upper_32_bits(mm->ppgtt_mm.shadow_pdps[0]);
+		*cmd_ptr(s, 4) = lower_32_bits(mm->ppgtt_mm.shadow_pdps[0]);
+	} else {
+		/* Currently all guests use PML4 table and now can't
+		 * have a guest with 3-level table but uses LRI for
+		 * PPGTT update. So this is simply un-testable. */
+		GEM_BUG_ON(1);
+		gvt_vgpu_err("invalid shared shadow vm type\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static int cmd_reg_handler(struct parser_exec_state *s,
 	unsigned int offset, unsigned int index, char *cmd)
 {
@@ -919,6 +960,10 @@ static int cmd_reg_handler(struct parser_exec_state *s,
 		patch_value(s, cmd_ptr(s, index), VGT_PVINFO_PAGE);
 	}
 
+	if (is_cmd_update_pdps(offset, s) &&
+	    cmd_pdp_mmio_update_handler(s, offset, index))
+		return -EINVAL;
+
 	/* TODO
 	 * In order to let workload with inhibit context to generate
 	 * correct image data into memory, vregs values will be loaded to