drm/i915/gvt: add RING_INSTDONE and SC_INSTDONE mmio handler in GVT-g

kernel hangcheck needs to check RING_INSTDONE and SC_INSTDONE registers'
state to know if hardware is still running. In GVT-g environment, we need
to emulate these registers changing for all the guests although they are
not render owner. Here we return the physical state for all the guests,
then if INSTDONE is changing guest can know hardware is still running
although its workload is pending.

Read INSTDONE isn't one correct way to know if guest trigger gfx reset,
especially with Linux guest, it will read ACTH first, then check INSTDONE
and SUBSLICE registers to check if hardware is still running, at last
trigger gfx reset when it finds all the registers is frozen. In Windows
guest, read INSTDONE usually happens when OS detect TDR.

With the difference between Windows and Linux guest, "disable_warn_untrack"
may let debug log run into wrong state(Linux guest trigger hangcheck
with no ACTHD changed, then check INSTDONE), but actually there is no TDR
happened.

The new policy is always WARN with untrack MMIO r/w. Bad effect is many
noisy untrack mmio warning logs exist when real TDR happen. Even so you can
control the log output or not by setting the debug mask bit.

v2: remove log in instdone_mmio_read

Suggested-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Weinan Li <weinan.z.li@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 0 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/gvt/mmio.c b/drivers/gpu/drm/i915/gvt/mmio.c
index 1ba3bdb09341..35f6c4713cb6 100644
--- a/drivers/gpu/drm/i915/gvt/mmio.c
+++ b/drivers/gpu/drm/i915/gvt/mmio.c
@@ -202,13 +202,6 @@ int intel_vgpu_emulate_mmio_read(struct intel_vgpu *vgpu, uint64_t pa,
 		if (!vgpu->mmio.disable_warn_untrack) {
 			gvt_vgpu_err("read untracked MMIO %x(%dB) val %x\n",
 				offset, bytes, *(u32 *)p_data);
-
-			if (offset == 0x206c) {
-				gvt_vgpu_err("------------------------------------------\n");
-				gvt_vgpu_err("likely triggers a gfx reset\n");
-				gvt_vgpu_err("------------------------------------------\n");
-				vgpu->mmio.disable_warn_untrack = true;
-			}
 		}
 	}