drm/amdgpu: set noretry=1 as default for GFX 10.1.x (Navi10/12/14)

Problem:
While developing the amd_close_race IGT test (which intentionally triggers
execute permission faults by removing VM_PAGE_EXECUTABLE from GPU page table
entries), we discovered that on Navi10 (GFX 10.1.x) these faults produce
zero diagnostic output. The GPU simply hangs silently for ~10s until the
scheduler timeout fires. There is no way to distinguish an execute
permission fault from any other type of GPU hang.

Root cause:
GFX 10.1.x defaults to noretry=0, which sets
RETRY_PERMISSION_OR_INVALID_PAGE_FAULT=1 in the GFXHUB UTCL2 registers
(gfxhub_v2_0.c line 313). With this bit set, permission faults (valid PTE,
wrong R/W/X bits) are handled entirely within the UTCL1/UTCL2 hardware
loop: UTCL2 returns an XNACK to UTCL1, and UTCL1 re-requests the
translation indefinitely, expecting software to eventually fix the
permission bits (as happens in SVM/HMM recovery). No interrupt of any kind
reaches the IH ring.

This is different from invalid-page faults (V=0) which DO generate a retry
fault interrupt that the driver can escalate to a no-retry fault. Permission
faults with valid PTEs loop silently forever in hardware.

GFX 10.3+ already defaults to noretry=1, which makes permission faults
generate immediate L2 protection fault interrupts. GFX 10.1.x was
inadvertently left out of this default.

Fix:
Change the noretry=1 threshold from IP_VERSION(10, 3, 0) to
IP_VERSION(10, 1, 0) in amdgpu_gmc_noretry_set(). This is a one-line
change that aligns GFX 10.1.x behavior with GFX 10.3+ and all newer
generations.

With noretry=1, the existing non-retry fault handler
(gmc_v10_0_process_interrupt) already decodes and prints the full
GCVM_L2_PROTECTION_FAULT_STATUS register including PERMISSION_FAULTS,
faulting address, VMID, PASID, and process name. No additional logging
code is needed — the fix is purely routing permission faults to the
existing, fully-capable non-retry interrupt handler.

v2: Dropped GFX10-specific logging from gmc_v10_0.c and
kfd_int_process_v10.c (Felix Kuehling). v1 added logging in the retry
fault handler, but with noretry=1 permission faults take the non-retry
path — the v1 retry handler code was dead and would never execute.

Tested on Navi10 (GFX 10.1.10):
- Execute permission faults now produce immediate, clear output:
    [gfxhub] page fault (src_id:0 ring:64 vmid:4 pasid:592)
     Process amd_close_race pid 13380 thread amd_close_race pid 13384
      in page at address 0x40001000 from client 0x1b (UTCL2)
    GCVM_L2_PROTECTION_FAULT_STATUS:0x00700881
         PERMISSION_FAULTS: 0x8
- No regressions with properly-mapped GPU workloads

Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit eb21edd24c40d81066753f8ac6f23bce15745395)
Cc: stable@vger.kernel.org

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
index 13a5acdf8da3..c076c5f06e77 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -1003,7 +1003,7 @@ void amdgpu_gmc_noretry_set(struct amdgpu_device *adev)
 				gc_ver == IP_VERSION(9, 4, 3) ||
 				gc_ver == IP_VERSION(9, 4, 4) ||
 				gc_ver == IP_VERSION(9, 5, 0) ||
-				gc_ver >= IP_VERSION(10, 3, 0));
+				gc_ver >= IP_VERSION(10, 1, 0));
 
 	if (!amdgpu_sriov_xnack_support(adev))
 		gmc->noretry = 1;