drm/amdgpu: Track pending retry faults in IH and VM (v2)

IH tracks pending retry faults in a hash table for fast lookup in
interrupt context. Each VM has a short FIFO of pending VM faults for
processing in a bottom half.

The IH prescreening stage adds retry faults and filters out repeated
retry interrupts to minimize the impact of interrupt storms.

It's the VM's responsibility remove pending faults once they are
handled. For now this is only done when the VM is destroyed.

v2:
- Made the hash table smaller and the FIFO longer. I never want the
  FIFO to fill up, because that would make prescreen take longer.
  128 pending page faults should be enough to keep migrations busy.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Christian König <christian.koenig@amd.com> (v1)
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 7873dfa8c0f9..447ed6e7e586 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -120,6 +120,10 @@ struct amdgpu_vm_pt {
 	unsigned			last_entry_used;
 };
 
+#define AMDGPU_VM_FAULT(pasid, addr) (((u64)(pasid) << 48) | (addr))
+#define AMDGPU_VM_FAULT_PASID(fault) ((u64)(fault) >> 48)
+#define AMDGPU_VM_FAULT_ADDR(fault)  ((u64)(fault) & 0xfffffffff000ULL)
+
 struct amdgpu_vm {
 	/* tree of virtual addresses mapped */
 	struct rb_root		va;
@@ -160,6 +164,9 @@ struct amdgpu_vm {
 
 	/* Flag to indicate ATS support from PTE for GFX9 */
 	bool			pte_support_ats;
+
+	/* Up to 128 pending page faults */
+	DECLARE_KFIFO(faults, u64, 128);
 };
 
 struct amdgpu_vm_id {