[Xen-devel] [RFC XEN PATCH v4 07/41] xen/pmem: register valid PMEM regions to Xen hypervisor

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

Register valid PMEM regions probed via NFIT to Xen hypervisor. No
frametable and M2P table are created for those PMEM regions at this
stage.

Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>

Changes in v4:
  * Simplify return paths of pmem_list_add().
---
 xen/common/Makefile     |   1 +
 xen/common/pmem.c       | 122 ++++++++++++++++++++++++++++++++++++++++++++++++
 xen/drivers/acpi/nfit.c |  12 ++++-
 xen/include/xen/pmem.h  |  28 +++++++++++
 4 files changed, 162 insertions(+), 1 deletion(-)
 create mode 100644 xen/common/pmem.c
 create mode 100644 xen/include/xen/pmem.h

diff --git a/xen/common/Makefile b/xen/common/Makefile
index 66cc2c8995..57fa4601b8 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -29,6 +29,7 @@ obj-y += notifier.o
 obj-y += page_alloc.o
 obj-$(CONFIG_HAS_PDX) += pdx.o
 obj-$(CONFIG_PERF_COUNTERS) += perfc.o
+obj-${CONFIG_NVDIMM_PMEM} += pmem.o
 obj-y += preempt.o
 obj-y += random.o
 obj-y += rangeset.o
diff --git a/xen/common/pmem.c b/xen/common/pmem.c
new file mode 100644
index 0000000000..aa0a1d166d
--- /dev/null
+++ b/xen/common/pmem.c
@@ -0,0 +1,122 @@
+/*
+ * xen/common/pmem.c
+ *
+ * Copyright (C) 2017, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/errno.h>
+#include <xen/list.h>
+#include <xen/pmem.h>
+
+/*
+ * All PMEM regions presenting in NFIT SPA range structures are linked
+ * in this list.
+ */
+static LIST_HEAD(pmem_raw_regions);
+static unsigned int nr_raw_regions;
+
+struct pmem {
+    struct list_head link; /* link to one of PMEM region list */
+    unsigned long smfn;    /* start MFN of the PMEM region */
+    unsigned long emfn;    /* end MFN of the PMEM region */
+
+    union {
+        struct {
+            unsigned int pxm; /* proximity domain of the PMEM region */
+        } raw;
+    } u;
+};
+
+static bool check_overlap(unsigned long smfn1, unsigned long emfn1,
+                          unsigned long smfn2, unsigned long emfn2)
+{
+    return (smfn1 >= smfn2 && smfn1 < emfn2) ||
+           (emfn1 > smfn2 && emfn1 <= emfn2);
+}
+
+/**
+ * Add a PMEM region to a list. All PMEM regions in the list are
+ * sorted in the ascending order of the start address. A PMEM region,
+ * whose range is overlapped with anyone in the list, cannot be added
+ * to the list.
+ *
+ * Parameters:
+ *  list:       the list to which a new PMEM region will be added
+ *  smfn, emfn: the range of the new PMEM region
+ *  entry:      return the new entry added to the list
+ *
+ * Return:
+ *  On success, return 0 and the new entry added to the list is
+ *  returned via @entry. Otherwise, return an error number and the
+ *  value of @entry is undefined.
+ */
+static int pmem_list_add(struct list_head *list,
+                         unsigned long smfn, unsigned long emfn,
+                         struct pmem **entry)
+{
+    struct list_head *cur;
+    struct pmem *new_pmem;
+
+    list_for_each_prev(cur, list)
+    {
+        struct pmem *cur_pmem = list_entry(cur, struct pmem, link);
+        unsigned long cur_smfn = cur_pmem->smfn;
+        unsigned long cur_emfn = cur_pmem->emfn;
+
+        if ( check_overlap(smfn, emfn, cur_smfn, cur_emfn) )
+            return -EEXIST;
+
+        if ( cur_smfn < smfn )
+            break;
+    }
+
+    new_pmem = xzalloc(struct pmem);
+    if ( !new_pmem )
+        return -ENOMEM;
+
+    new_pmem->smfn = smfn;
+    new_pmem->emfn = emfn;
+    list_add(&new_pmem->link, cur);
+    if ( entry )
+        *entry = new_pmem;
+
+    return 0;
+}
+
+/**
+ * Register a pmem region to Xen.
+ *
+ * Parameters:
+ *  smfn, emfn: start and end MFNs of the pmem region
+ *  pxm:        the proximity domain of the pmem region
+ *
+ * Return:
+ *  On success, return 0. Otherwise, an error number is returned.
+ */
+int pmem_register(unsigned long smfn, unsigned long emfn, unsigned int pxm)
+{
+    int rc;
+    struct pmem *pmem;
+
+    if ( smfn >= emfn )
+        return -EINVAL;
+
+    rc = pmem_list_add(&pmem_raw_regions, smfn, emfn, &pmem);
+    if ( !rc )
+        pmem->u.raw.pxm = pxm;
+    nr_raw_regions++;
+
+    return rc;
+}
diff --git a/xen/drivers/acpi/nfit.c b/xen/drivers/acpi/nfit.c
index 0a44983aad..6f85d4d911 100644
--- a/xen/drivers/acpi/nfit.c
+++ b/xen/drivers/acpi/nfit.c
@@ -20,6 +20,7 @@
 #include <xen/init.h>
 #include <xen/mm.h>
 #include <xen/pfn.h>
+#include <xen/pmem.h>
 
 /*
  * GUID of a byte addressable persistent memory region
@@ -153,6 +154,7 @@ static void __init acpi_nfit_register_pmem(struct 
acpi_nfit_desc *desc)
     struct acpi_nfit_system_address *spa;
     unsigned long smfn, emfn;
     bool failed;
+    int rc;
 
     list_for_each_entry(spa_desc, &desc->spa_list, link)
     {
@@ -188,7 +190,15 @@ static void __init acpi_nfit_register_pmem(struct 
acpi_nfit_desc *desc)
             continue;
         }
 
-        printk(XENLOG_INFO "NFIT: PMEM MFNs 0x%lx - 0x%lx\n", smfn, emfn);
+        rc = pmem_register(smfn, emfn, spa->proximity_domain);
+        if ( !rc )
+            printk(XENLOG_INFO
+                   "NFIT: PMEM MFNs 0x%lx - 0x%lx on PXM %u registered\n",
+                   smfn, emfn, spa->proximity_domain);
+        else
+            printk(XENLOG_ERR
+                   "NFIT: failed to register PMEM MFNs 0x%lx - 0x%lx on PXM 
%u, err %d\n",
+                   smfn, emfn, spa->proximity_domain, rc);
     }
 }
 
diff --git a/xen/include/xen/pmem.h b/xen/include/xen/pmem.h
new file mode 100644
index 0000000000..41cb9bb04f
--- /dev/null
+++ b/xen/include/xen/pmem.h
@@ -0,0 +1,28 @@
+/*
+ * xen/include/xen/pmem.h
+ *
+ * Copyright (C) 2017, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __XEN_PMEM_H__
+#define __XEN_PMEM_H__
+#ifdef CONFIG_NVDIMM_PMEM
+
+#include <xen/types.h>
+
+int pmem_register(unsigned long smfn, unsigned long emfn, unsigned int pxm);
+
+#endif /* CONFIG_NVDIMM_PMEM */
+#endif /* __XEN_PMEM_H__ */
-- 
2.15.1


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