From eaef510728b5fbe80138046668ab5b3199a5b5fa Mon Sep 17 00:00:00 2001
From: Philip Yang <Philip.Yang@amd.com>
Date: Mon, 18 Apr 2022 21:32:14 -0400
Subject: drm/amdkfd: Add SVM range mapped_to_gpu flag
Git-commit: 6b9c63a6eb540e678504a080865e9d3c716288ed
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

To avoid unnecessary unmap SVM range from GPUs if range is not mapped on
GPUs when migrating the range. This flag will also be used to flush TLB
when updating the existing mapping on GPUs.

It is protected by prange->migrate_mutex and mmap read lock in MMU
notifier callback.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 17 ++++++++++++++++-
 drivers/gpu/drm/amd/amdkfd/kfd_svm.h |  1 +
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index b166dc8294f6..4aba3eea903e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -950,6 +950,7 @@ svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
 	new->prefetch_loc = old->prefetch_loc;
 	new->actual_loc = old->actual_loc;
 	new->granularity = old->granularity;
+	new->mapped_to_gpu = old->mapped_to_gpu;
 	bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
 	bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);
 
@@ -1203,6 +1204,17 @@ svm_range_unmap_from_gpus(struct svm_range *prange, unsigned long start,
 	uint32_t gpuidx;
 	int r = 0;
 
+	if (!prange->mapped_to_gpu) {
+		pr_debug("prange 0x%p [0x%lx 0x%lx] not mapped to GPU\n",
+			 prange, prange->start, prange->last);
+		return 0;
+	}
+
+	if (prange->start == start && prange->last == last) {
+		pr_debug("unmap svms 0x%p prange 0x%p\n", prange->svms, prange);
+		prange->mapped_to_gpu = false;
+	}
+
 	bitmap_or(bitmap, prange->bitmap_access, prange->bitmap_aip,
 		  MAX_GPU_INSTANCE);
 	p = container_of(prange->svms, struct kfd_process, svms);
@@ -1587,8 +1599,10 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
 		addr = next;
 	}
 
-	if (addr == end)
+	if (addr == end) {
 		prange->validated_once = true;
+		prange->mapped_to_gpu = true;
+	}
 
 unreserve_out:
 	svm_range_unreserve_bos(&ctx);
@@ -1819,6 +1833,7 @@ static struct svm_range *svm_range_clone(struct svm_range *old)
 	new->prefetch_loc = old->prefetch_loc;
 	new->actual_loc = old->actual_loc;
 	new->granularity = old->granularity;
+	new->mapped_to_gpu = old->mapped_to_gpu;
 	bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
 	bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index 66c77f00ac3e..2d54147b4dda 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -133,6 +133,7 @@ struct svm_range {
 	DECLARE_BITMAP(bitmap_access, MAX_GPU_INSTANCE);
 	DECLARE_BITMAP(bitmap_aip, MAX_GPU_INSTANCE);
 	bool				validated_once;
+	bool				mapped_to_gpu;
 };
 
 static inline void svm_range_lock(struct svm_range *prange)
-- 
2.38.1