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-rw-r--r--arch/x86/xen/grant-table.c169
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
new file mode 100644
index 0000000000..1e681bf625
--- /dev/null
+++ b/arch/x86/xen/grant-table.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/******************************************************************************
+ * grant_table.c
+ * x86 specific part
+ *
+ * Granting foreign access to our memory reservation.
+ *
+ * Copyright (c) 2005-2006, Christopher Clark
+ * Copyright (c) 2004-2005, K A Fraser
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ * VA Linux Systems Japan. Split out x86 specific part.
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <xen/interface/xen.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+#include <xen/xen.h>
+
+
+static struct gnttab_vm_area {
+ struct vm_struct *area;
+ pte_t **ptes;
+ int idx;
+} gnttab_shared_vm_area, gnttab_status_vm_area;
+
+int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
+ unsigned long max_nr_gframes,
+ void **__shared)
+{
+ void *shared = *__shared;
+ unsigned long addr;
+ unsigned long i;
+
+ if (shared == NULL)
+ *__shared = shared = gnttab_shared_vm_area.area->addr;
+
+ addr = (unsigned long)shared;
+
+ for (i = 0; i < nr_gframes; i++) {
+ set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
+ mfn_pte(frames[i], PAGE_KERNEL));
+ addr += PAGE_SIZE;
+ }
+
+ return 0;
+}
+
+int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
+ unsigned long max_nr_gframes,
+ grant_status_t **__shared)
+{
+ grant_status_t *shared = *__shared;
+ unsigned long addr;
+ unsigned long i;
+
+ if (shared == NULL)
+ *__shared = shared = gnttab_status_vm_area.area->addr;
+
+ addr = (unsigned long)shared;
+
+ for (i = 0; i < nr_gframes; i++) {
+ set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
+ mfn_pte(frames[i], PAGE_KERNEL));
+ addr += PAGE_SIZE;
+ }
+
+ return 0;
+}
+
+void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
+{
+ pte_t **ptes;
+ unsigned long addr;
+ unsigned long i;
+
+ if (shared == gnttab_status_vm_area.area->addr)
+ ptes = gnttab_status_vm_area.ptes;
+ else
+ ptes = gnttab_shared_vm_area.ptes;
+
+ addr = (unsigned long)shared;
+
+ for (i = 0; i < nr_gframes; i++) {
+ set_pte_at(&init_mm, addr, ptes[i], __pte(0));
+ addr += PAGE_SIZE;
+ }
+}
+
+static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
+{
+ struct gnttab_vm_area *area = data;
+
+ area->ptes[area->idx++] = pte;
+ return 0;
+}
+
+static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
+{
+ area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
+ if (area->ptes == NULL)
+ return -ENOMEM;
+ area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
+ if (!area->area)
+ goto out_free_ptes;
+ if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
+ PAGE_SIZE * nr_frames, gnttab_apply, area))
+ goto out_free_vm_area;
+ return 0;
+out_free_vm_area:
+ free_vm_area(area->area);
+out_free_ptes:
+ kfree(area->ptes);
+ return -ENOMEM;
+}
+
+static void arch_gnttab_vfree(struct gnttab_vm_area *area)
+{
+ free_vm_area(area->area);
+ kfree(area->ptes);
+}
+
+int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
+{
+ int ret;
+
+ if (!xen_pv_domain())
+ return 0;
+
+ ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Always allocate the space for the status frames in case
+ * we're migrated to a host with V2 support.
+ */
+ ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
+ if (ret < 0)
+ goto err;
+
+ return 0;
+err:
+ arch_gnttab_vfree(&gnttab_shared_vm_area);
+ return -ENOMEM;
+}
+
+#ifdef CONFIG_XEN_PVH
+#include <xen/events.h>
+#include <xen/xen-ops.h>
+static int __init xen_pvh_gnttab_setup(void)
+{
+ if (!xen_pvh_domain())
+ return -ENODEV;
+
+ xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
+
+ return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
+ &xen_auto_xlat_grant_frames.vaddr,
+ xen_auto_xlat_grant_frames.count);
+}
+/* Call it _before_ __gnttab_init as we need to initialize the
+ * xen_auto_xlat_grant_frames first. */
+core_initcall(xen_pvh_gnttab_setup);
+#endif