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From:   Alex Sierra <alex.sierra@amd.com>
To:     <akpm@linux-foundation.org>, <Felix.Kuehling@amd.com>,
        <linux-mm@kvack.org>, <rcampbell@nvidia.com>,
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Subject: [PATCH v1 09/12] lib: test_hmm add module param for zone device type
Date:   Tue, 12 Oct 2021 12:12:44 -0500
Message-ID: <20211012171247.2861-10-alex.sierra@amd.com>
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In order to configure device coherent in test_hmm, two module parameters
should be passed, which correspond to the SP start address of each
device (2) spm_addr_dev0 & spm_addr_dev1. If no parameters are passed,
private device type is configured.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
---
 lib/test_hmm.c      | 66 +++++++++++++++++++++++++++++++--------------
 lib/test_hmm_uapi.h |  1 +
 2 files changed, 47 insertions(+), 20 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 3cd91ca31dd7..70a9be0efa00 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -33,6 +33,16 @@
 #define DEVMEM_CHUNK_SIZE		(256 * 1024 * 1024U)
 #define DEVMEM_CHUNKS_RESERVE		16
 
+static unsigned long spm_addr_dev0;
+module_param(spm_addr_dev0, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev0,
+		"Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too");
+
+static unsigned long spm_addr_dev1;
+module_param(spm_addr_dev1, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev1,
+		"Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too");
+
 static const struct dev_pagemap_ops dmirror_devmem_ops;
 static const struct mmu_interval_notifier_ops dmirror_min_ops;
 static dev_t dmirror_dev;
@@ -450,11 +460,11 @@ static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
 	return ret;
 }
 
-static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 				   struct page **ppage)
 {
 	struct dmirror_chunk *devmem;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long pfn;
 	unsigned long pfn_first;
 	unsigned long pfn_last;
@@ -462,17 +472,29 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 
 	devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
 	if (!devmem)
-		return false;
+		return -ENOMEM;
 
-	res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
-				      "hmm_dmirror");
-	if (IS_ERR(res))
-		goto err_devmem;
+	if (!spm_addr_dev0 && !spm_addr_dev1) {
+		res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
+					      "hmm_dmirror");
+		if (IS_ERR_OR_NULL(res))
+			goto err_devmem;
+		devmem->pagemap.range.start = res->start;
+		devmem->pagemap.range.end = res->end;
+		devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+		mdevice->zone_device_type = HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	} else if (spm_addr_dev0 && spm_addr_dev1) {
+		devmem->pagemap.range.start = MINOR(mdevice->cdevice.dev) ?
+							spm_addr_dev0 :
+							spm_addr_dev1;
+		devmem->pagemap.range.end = devmem->pagemap.range.start +
+					    DEVMEM_CHUNK_SIZE - 1;
+		devmem->pagemap.type = MEMORY_DEVICE_COHERENT;
+		mdevice->zone_device_type = HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+	} else {
+		pr_err("Both spm_addr_dev parameters should be set\n");
+	}
 
-	mdevice->zone_device_type = HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
-	devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
-	devmem->pagemap.range.start = res->start;
-	devmem->pagemap.range.end = res->end;
 	devmem->pagemap.nr_range = 1;
 	devmem->pagemap.ops = &dmirror_devmem_ops;
 	devmem->pagemap.owner = mdevice;
@@ -493,10 +515,14 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 		mdevice->devmem_capacity = new_capacity;
 		mdevice->devmem_chunks = new_chunks;
 	}
-
 	ptr = memremap_pages(&devmem->pagemap, numa_node_id());
-	if (IS_ERR(ptr))
+	if (IS_ERR_OR_NULL(ptr)) {
+		if (ptr)
+			ret = PTR_ERR(ptr);
+		else
+			ret = -EFAULT;
 		goto err_release;
+	}
 
 	devmem->mdevice = mdevice;
 	pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT;
@@ -529,7 +555,8 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 
 err_release:
 	mutex_unlock(&mdevice->devmem_lock);
-	release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
+	if (res)
+		release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
 err_devmem:
 	kfree(devmem);
 
@@ -1097,10 +1124,8 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
 	if (ret)
 		return ret;
 
-	/* Build a list of free ZONE_DEVICE private struct pages */
-	dmirror_allocate_chunk(mdevice, NULL);
-
-	return 0;
+	/* Build a list of free ZONE_DEVICE struct pages */
+	return dmirror_allocate_chunk(mdevice, NULL);
 }
 
 static void dmirror_device_remove(struct dmirror_device *mdevice)
@@ -1113,8 +1138,9 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
 				mdevice->devmem_chunks[i];
 
 			memunmap_pages(&devmem->pagemap);
-			release_mem_region(devmem->pagemap.range.start,
-					   range_len(&devmem->pagemap.range));
+			if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+				release_mem_region(devmem->pagemap.range.start,
+						   range_len(&devmem->pagemap.range));
 			kfree(devmem);
 		}
 		kfree(mdevice->devmem_chunks);
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index ee88701793d5..f86754be64fd 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -65,6 +65,7 @@ enum {
 enum {
 	/* 0 is reserved to catch uninitialized type fields */
 	HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+	HMM_DMIRROR_MEMORY_DEVICE_COHERENT,
 };
 
 #endif /* _LIB_TEST_HMM_UAPI_H */
-- 
2.32.0