[PATCH v1 7/9] lib: add support for device coherent type in test_hmm
Alex Sierra
alex.sierra at amd.com
Mon Nov 15 19:30:24 UTC 2021
Device Coherent type uses device memory that is coherently accesible by
the CPU. This could be shown as SP (special purpose) memory range
at the BIOS-e820 memory enumeration. If no SP memory is supported in
system, this could be faked by setting CONFIG_EFI_FAKE_MEMMAP.
Currently, test_hmm only supports two different SP ranges of at least
256MB size. This could be specified in the kernel parameter variable
efi_fake_mem. Ex. Two SP ranges of 1GB starting at 0x100000000 &
0x140000000 physical address. Ex.
efi_fake_mem=1G at 0x100000000:0x40000,1G at 0x140000000:0x40000
Signed-off-by: Alex Sierra <alex.sierra at amd.com>
---
lib/test_hmm.c | 191 +++++++++++++++++++++++++++++++++-----------
lib/test_hmm_uapi.h | 15 ++--
2 files changed, 153 insertions(+), 53 deletions(-)
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 45334df28d7b..9e2cc0cd4412 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -471,6 +471,7 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
unsigned long pfn_first;
unsigned long pfn_last;
void *ptr;
+ int ret = -ENOMEM;
devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
if (!devmem)
@@ -553,7 +554,7 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
}
spin_unlock(&mdevice->lock);
- return true;
+ return 0;
err_release:
mutex_unlock(&mdevice->devmem_lock);
@@ -562,7 +563,7 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
err_devmem:
kfree(devmem);
- return false;
+ return ret;
}
static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
@@ -571,8 +572,10 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
struct page *rpage;
/*
- * This is a fake device so we alloc real system memory to store
- * our device memory.
+ * For ZONE_DEVICE private type, this is a fake device so we alloc real
+ * system memory to store our device memory.
+ * For ZONE_DEVICE coherent type we use the actual dpage to store the data
+ * and ignore rpage.
*/
rpage = alloc_page(GFP_HIGHUSER);
if (!rpage)
@@ -623,12 +626,17 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
* unallocated pte_none() or read-only zero page.
*/
spage = migrate_pfn_to_page(*src);
+ if (spage && is_zone_device_page(spage))
+ pr_err("page already in device spage pfn: 0x%lx\n",
+ page_to_pfn(spage));
+ WARN_ON(spage && is_zone_device_page(spage));
dpage = dmirror_devmem_alloc_page(mdevice);
if (!dpage)
continue;
- rpage = dpage->zone_device_data;
+ rpage = is_device_private_page(dpage) ? dpage->zone_device_data :
+ dpage;
if (spage)
copy_highpage(rpage, spage);
else
@@ -640,8 +648,11 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
* the simulated device memory and that page holds the pointer
* to the mirror.
*/
+ rpage = dpage->zone_device_data;
rpage->zone_device_data = dmirror;
+ pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
+ page_to_pfn(spage), page_to_pfn(dpage));
*dst = migrate_pfn(page_to_pfn(dpage)) |
MIGRATE_PFN_LOCKED;
if ((*src & MIGRATE_PFN_WRITE) ||
@@ -721,10 +732,13 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
continue;
/*
- * Store the page that holds the data so the page table
- * doesn't have to deal with ZONE_DEVICE private pages.
+ * For ZONE_DEVICE private pages we store the page that
+ * holds the data so the page table doesn't have to deal it.
+ * For ZONE_DEVICE coherent pages we store the actual page, since
+ * the CPU has coherent access to the page.
*/
- entry = dpage->zone_device_data;
+ entry = is_device_private_page(dpage) ? dpage->zone_device_data :
+ dpage;
if (*dst & MIGRATE_PFN_WRITE)
entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
@@ -804,8 +818,110 @@ static int dmirror_exclusive(struct dmirror *dmirror,
return ret;
}
-static int dmirror_migrate(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
+static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
+ struct dmirror *dmirror)
+{
+ const unsigned long *src = args->src;
+ unsigned long *dst = args->dst;
+ unsigned long start = args->start;
+ unsigned long end = args->end;
+ unsigned long addr;
+
+ for (addr = start; addr < end; addr += PAGE_SIZE,
+ src++, dst++) {
+ struct page *dpage, *spage;
+
+ spage = migrate_pfn_to_page(*src);
+ if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
+ continue;
+
+ WARN_ON(!is_device_page(spage));
+ spage = is_device_private_page(spage) ? spage->zone_device_data :
+ spage;
+ dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
+ if (!dpage)
+ continue;
+ pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
+ page_to_pfn(spage), page_to_pfn(dpage));
+
+ lock_page(dpage);
+ xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
+ copy_highpage(dpage, spage);
+ *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
+ if (*src & MIGRATE_PFN_WRITE)
+ *dst |= MIGRATE_PFN_WRITE;
+ }
+ return 0;
+}
+
+static int dmirror_migrate_to_system(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ unsigned long start, end, addr;
+ unsigned long size = cmd->npages << PAGE_SHIFT;
+ struct mm_struct *mm = dmirror->notifier.mm;
+ struct vm_area_struct *vma;
+ unsigned long src_pfns[64];
+ unsigned long dst_pfns[64];
+ struct migrate_vma args;
+ unsigned long next;
+ int ret;
+
+ start = cmd->addr;
+ end = start + size;
+ if (end < start)
+ return -EINVAL;
+
+ /* Since the mm is for the mirrored process, get a reference first. */
+ if (!mmget_not_zero(mm))
+ return -EINVAL;
+
+ mmap_read_lock(mm);
+ for (addr = start; addr < end; addr = next) {
+ vma = find_vma(mm, addr);
+ if (!vma || addr < vma->vm_start ||
+ !(vma->vm_flags & VM_READ)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+ if (next > vma->vm_end)
+ next = vma->vm_end;
+
+ args.vma = vma;
+ args.src = src_pfns;
+ args.dst = dst_pfns;
+ args.start = addr;
+ args.end = next;
+ args.pgmap_owner = dmirror->mdevice;
+ args.flags = (dmirror->mdevice->zone_device_type ==
+ HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ?
+ MIGRATE_VMA_SELECT_DEVICE_PRIVATE :
+ MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+
+ ret = migrate_vma_setup(&args);
+ if (ret)
+ goto out;
+
+ pr_debug("Migrating from device mem to sys mem\n");
+ dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
+
+ migrate_vma_pages(&args);
+ migrate_vma_finalize(&args);
+ }
+ mmap_read_unlock(mm);
+ mmput(mm);
+
+ return ret;
+
+out:
+ mmap_read_unlock(mm);
+ mmput(mm);
+ return ret;
+}
+
+static int dmirror_migrate_to_device(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
{
unsigned long start, end, addr;
unsigned long size = cmd->npages << PAGE_SHIFT;
@@ -849,6 +965,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
if (ret)
goto out;
+ pr_debug("Migrating from sys mem to device mem\n");
dmirror_migrate_alloc_and_copy(&args, dmirror);
migrate_vma_pages(&args);
dmirror_migrate_finalize_and_map(&args, dmirror);
@@ -857,7 +974,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
mmap_read_unlock(mm);
mmput(mm);
- /* Return the migrated data for verification. */
+ /* Return the migrated data for verification. only for pages in device zone */
ret = dmirror_bounce_init(&bounce, start, size);
if (ret)
return ret;
@@ -894,9 +1011,15 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
}
page = hmm_pfn_to_page(entry);
- if (is_device_private_page(page)) {
- /* Is the page migrated to this device or some other? */
- if (dmirror->mdevice == dmirror_page_to_device(page))
+ if (is_device_page(page)) {
+ /* Is page ZONE_DEVICE coherent? */
+ if (!is_device_private_page(page))
+ *perm = HMM_DMIRROR_PROT_DEV_COHERENT;
+ /*
+ * Is page ZONE_DEVICE private migrated to
+ * this device or some other?
+ */
+ else if (dmirror->mdevice == dmirror_page_to_device(page))
*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
else
*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
@@ -1096,8 +1219,12 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
ret = dmirror_write(dmirror, &cmd);
break;
- case HMM_DMIRROR_MIGRATE:
- ret = dmirror_migrate(dmirror, &cmd);
+ case HMM_DMIRROR_MIGRATE_TO_DEV:
+ ret = dmirror_migrate_to_device(dmirror, &cmd);
+ break;
+
+ case HMM_DMIRROR_MIGRATE_TO_SYS:
+ ret = dmirror_migrate_to_system(dmirror, &cmd);
break;
case HMM_DMIRROR_EXCLUSIVE:
@@ -1152,38 +1279,6 @@ static void dmirror_devmem_free(struct page *page)
spin_unlock(&mdevice->lock);
}
-static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
-{
- const unsigned long *src = args->src;
- unsigned long *dst = args->dst;
- unsigned long start = args->start;
- unsigned long end = args->end;
- unsigned long addr;
-
- for (addr = start; addr < end; addr += PAGE_SIZE,
- src++, dst++) {
- struct page *dpage, *spage;
-
- spage = migrate_pfn_to_page(*src);
- if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
- continue;
- spage = spage->zone_device_data;
-
- dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
- if (!dpage)
- continue;
-
- lock_page(dpage);
- xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
- copy_highpage(dpage, spage);
- *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
- if (*src & MIGRATE_PFN_WRITE)
- *dst |= MIGRATE_PFN_WRITE;
- }
- return 0;
-}
-
static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
{
struct migrate_vma args;
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 77f81e6314eb..af15c35a90f4 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -19,6 +19,7 @@
* @npages: (in) number of pages to read/write
* @cpages: (out) number of pages copied
* @faults: (out) number of device page faults seen
+ * @zone_device_type: (out) zone device memory type
*/
struct hmm_dmirror_cmd {
__u64 addr;
@@ -32,11 +33,12 @@ struct hmm_dmirror_cmd {
/* Expose the address space of the calling process through hmm device file */
#define HMM_DMIRROR_READ _IOWR('H', 0x00, struct hmm_dmirror_cmd)
#define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_MIGRATE _IOWR('H', 0x02, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x03, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x04, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_GET_MEM_DEV_TYPE _IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_DEV _IOWR('H', 0x02, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_SYS _IOWR('H', 0x03, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x04, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_GET_MEM_DEV_TYPE _IOWR('H', 0x07, struct hmm_dmirror_cmd)
/*
* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -51,6 +53,8 @@ struct hmm_dmirror_cmd {
* device the ioctl() is made
* HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
* other device
+ * HMM_DMIRROR_PROT_DEV_COHERENT: Migrate device coherent page on the device
+ * the ioctl() is made
*/
enum {
HMM_DMIRROR_PROT_ERROR = 0xFF,
@@ -62,6 +66,7 @@ enum {
HMM_DMIRROR_PROT_ZERO = 0x10,
HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL = 0x20,
HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,
+ HMM_DMIRROR_PROT_DEV_COHERENT = 0x40,
};
enum {
--
2.32.0
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