Re: [PATCH v2 09/12] lib: test_hmm add module param for zone device type

Alistair Popple
2021-09-20T08:54:05Z

On Tuesday, 14 September 2021 2:16:01 AM AEST Alex Sierra wrote:
> In order to configure device public 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.

It's a pity that testing this seems to require some amount of special setup to
test. Is there a way this could be made to work on a more standard setup
similar to how DEVICE_PRIVATE is tested?

> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> ---
> v5:
> Remove devmem->pagemap.type = MEMORY_DEVICE_PRIVATE at
> dmirror_allocate_chunk that was forcing to configure pagemap.type
> to MEMORY_DEVICE_PRIVATE
>
> v6:
> Check for null pointers for resource and memremap references
> at dmirror_allocate_chunk
>
> v7:
> Due to patch dropped from these patch series "kernel: resource:
> lookup_resource as exported symbol", lookup_resource was not longer a
> callable function. This was used in public device configuration, to
> get start and end addresses, to create pgmap->range struct. This
> information is now taken directly from the spm_addr_devX parameters and
> the fixed size DEVMEM_CHUNK_SIZE.
> ---
> 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..ef27e355738a 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 Generic 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 Generic 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_PUBLIC;
> + mdevice->zone_device_type = HMM_DMIRROR_MEMORY_DEVICE_PUBLIC;
> + } 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..00259d994410 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_PUBLIC,
> };
>
> #endif /* _LIB_TEST_HMM_UAPI_H */
>