Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 988 insertions, 0 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
new file mode 100644
index 0000000000..b3e3796106
--- /dev/null
+++ b/arch/x86/xen/setup.c
@@ -0,0 +1,988 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Machine specific setup for xen
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#include <linux/init.h>
+#include <linux/iscsi_ibft.h>
+#include <linux/sched.h>
+#include <linux/kstrtox.h>
+#include <linux/mm.h>
+#include <linux/pm.h>
+#include <linux/memblock.h>
+#include <linux/cpuidle.h>
+#include <linux/cpufreq.h>
+#include <linux/memory_hotplug.h>
+
+#include <asm/elf.h>
+#include <asm/vdso.h>
+#include <asm/e820/api.h>
+#include <asm/setup.h>
+#include <asm/acpi.h>
+#include <asm/numa.h>
+#include <asm/idtentry.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/callback.h>
+#include <xen/interface/memory.h>
+#include <xen/interface/physdev.h>
+#include <xen/features.h>
+#include <xen/hvc-console.h>
+#include "xen-ops.h"
+#include "mmu.h"
+
+#define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024)
+
+/* Amount of extra memory space we add to the e820 ranges */
+struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
+
+/* Number of pages released from the initial allocation. */
+unsigned long xen_released_pages;
+
+/* Memory map would allow PCI passthrough. */
+bool xen_pv_pci_possible;
+
+/* E820 map used during setting up memory. */
+static struct e820_table xen_e820_table __initdata;
+
+/*
+ * Buffer used to remap identity mapped pages. We only need the virtual space.
+ * The physical page behind this address is remapped as needed to different
+ * buffer pages.
+ */
+#define REMAP_SIZE	(P2M_PER_PAGE - 3)
+static struct {
+	unsigned long	next_area_mfn;
+	unsigned long	target_pfn;
+	unsigned long	size;
+	unsigned long	mfns[REMAP_SIZE];
+} xen_remap_buf __initdata __aligned(PAGE_SIZE);
+static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
+
+/*
+ * The maximum amount of extra memory compared to the base size.  The
+ * main scaling factor is the size of struct page.  At extreme ratios
+ * of base:extra, all the base memory can be filled with page
+ * structures for the extra memory, leaving no space for anything
+ * else.
+ *
+ * 10x seems like a reasonable balance between scaling flexibility and
+ * leaving a practically usable system.
+ */
+#define EXTRA_MEM_RATIO		(10)
+
+static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB);
+
+static void __init xen_parse_512gb(void)
+{
+	bool val = false;
+	char *arg;
+
+	arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit");
+	if (!arg)
+		return;
+
+	arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit=");
+	if (!arg)
+		val = true;
+	else if (kstrtobool(arg + strlen("xen_512gb_limit="), &val))
+		return;
+
+	xen_512gb_limit = val;
+}
+
+static void __init xen_add_extra_mem(unsigned long start_pfn,
+				     unsigned long n_pfns)
+{
+	int i;
+
+	/*
+	 * No need to check for zero size, should happen rarely and will only
+	 * write a new entry regarded to be unused due to zero size.
+	 */
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		/* Add new region. */
+		if (xen_extra_mem[i].n_pfns == 0) {
+			xen_extra_mem[i].start_pfn = start_pfn;
+			xen_extra_mem[i].n_pfns = n_pfns;
+			break;
+		}
+		/* Append to existing region. */
+		if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
+		    start_pfn) {
+			xen_extra_mem[i].n_pfns += n_pfns;
+			break;
+		}
+	}
+	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
+		printk(KERN_WARNING "Warning: not enough extra memory regions\n");
+
+	memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
+}
+
+static void __init xen_del_extra_mem(unsigned long start_pfn,
+				     unsigned long n_pfns)
+{
+	int i;
+	unsigned long start_r, size_r;
+
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		start_r = xen_extra_mem[i].start_pfn;
+		size_r = xen_extra_mem[i].n_pfns;
+
+		/* Start of region. */
+		if (start_r == start_pfn) {
+			BUG_ON(n_pfns > size_r);
+			xen_extra_mem[i].start_pfn += n_pfns;
+			xen_extra_mem[i].n_pfns -= n_pfns;
+			break;
+		}
+		/* End of region. */
+		if (start_r + size_r == start_pfn + n_pfns) {
+			BUG_ON(n_pfns > size_r);
+			xen_extra_mem[i].n_pfns -= n_pfns;
+			break;
+		}
+		/* Mid of region. */
+		if (start_pfn > start_r && start_pfn < start_r + size_r) {
+			BUG_ON(start_pfn + n_pfns > start_r + size_r);
+			xen_extra_mem[i].n_pfns = start_pfn - start_r;
+			/* Calling memblock_reserve() again is okay. */
+			xen_add_extra_mem(start_pfn + n_pfns, start_r + size_r -
+					  (start_pfn + n_pfns));
+			break;
+		}
+	}
+	memblock_phys_free(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
+}
+
+/*
+ * Called during boot before the p2m list can take entries beyond the
+ * hypervisor supplied p2m list. Entries in extra mem are to be regarded as
+ * invalid.
+ */
+unsigned long __ref xen_chk_extra_mem(unsigned long pfn)
+{
+	int i;
+
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		if (pfn >= xen_extra_mem[i].start_pfn &&
+		    pfn < xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns)
+			return INVALID_P2M_ENTRY;
+	}
+
+	return IDENTITY_FRAME(pfn);
+}
+
+/*
+ * Mark all pfns of extra mem as invalid in p2m list.
+ */
+void __init xen_inv_extra_mem(void)
+{
+	unsigned long pfn, pfn_s, pfn_e;
+	int i;
+
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		if (!xen_extra_mem[i].n_pfns)
+			continue;
+		pfn_s = xen_extra_mem[i].start_pfn;
+		pfn_e = pfn_s + xen_extra_mem[i].n_pfns;
+		for (pfn = pfn_s; pfn < pfn_e; pfn++)
+			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+	}
+}
+
+/*
+ * Finds the next RAM pfn available in the E820 map after min_pfn.
+ * This function updates min_pfn with the pfn found and returns
+ * the size of that range or zero if not found.
+ */
+static unsigned long __init xen_find_pfn_range(unsigned long *min_pfn)
+{
+	const struct e820_entry *entry = xen_e820_table.entries;
+	unsigned int i;
+	unsigned long done = 0;
+
+	for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
+		unsigned long s_pfn;
+		unsigned long e_pfn;
+
+		if (entry->type != E820_TYPE_RAM)
+			continue;
+
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
+
+		/* We only care about E820 after this */
+		if (e_pfn <= *min_pfn)
+			continue;
+
+		s_pfn = PFN_UP(entry->addr);
+
+		/* If min_pfn falls within the E820 entry, we want to start
+		 * at the min_pfn PFN.
+		 */
+		if (s_pfn <= *min_pfn) {
+			done = e_pfn - *min_pfn;
+		} else {
+			done = e_pfn - s_pfn;
+			*min_pfn = s_pfn;
+		}
+		break;
+	}
+
+	return done;
+}
+
+static int __init xen_free_mfn(unsigned long mfn)
+{
+	struct xen_memory_reservation reservation = {
+		.address_bits = 0,
+		.extent_order = 0,
+		.domid        = DOMID_SELF
+	};
+
+	set_xen_guest_handle(reservation.extent_start, &mfn);
+	reservation.nr_extents = 1;
+
+	return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+}
+
+/*
+ * This releases a chunk of memory and then does the identity map. It's used
+ * as a fallback if the remapping fails.
+ */
+static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
+			unsigned long end_pfn, unsigned long nr_pages)
+{
+	unsigned long pfn, end;
+	int ret;
+
+	WARN_ON(start_pfn > end_pfn);
+
+	/* Release pages first. */
+	end = min(end_pfn, nr_pages);
+	for (pfn = start_pfn; pfn < end; pfn++) {
+		unsigned long mfn = pfn_to_mfn(pfn);
+
+		/* Make sure pfn exists to start with */
+		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
+			continue;
+
+		ret = xen_free_mfn(mfn);
+		WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
+
+		if (ret == 1) {
+			xen_released_pages++;
+			if (!__set_phys_to_machine(pfn, INVALID_P2M_ENTRY))
+				break;
+		} else
+			break;
+	}
+
+	set_phys_range_identity(start_pfn, end_pfn);
+}
+
+/*
+ * Helper function to update the p2m and m2p tables and kernel mapping.
+ */
+static void __init xen_update_mem_tables(unsigned long pfn, unsigned long mfn)
+{
+	struct mmu_update update = {
+		.ptr = ((uint64_t)mfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE,
+		.val = pfn
+	};
+
+	/* Update p2m */
+	if (!set_phys_to_machine(pfn, mfn)) {
+		WARN(1, "Failed to set p2m mapping for pfn=%ld mfn=%ld\n",
+		     pfn, mfn);
+		BUG();
+	}
+
+	/* Update m2p */
+	if (HYPERVISOR_mmu_update(&update, 1, NULL, DOMID_SELF) < 0) {
+		WARN(1, "Failed to set m2p mapping for mfn=%ld pfn=%ld\n",
+		     mfn, pfn);
+		BUG();
+	}
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)__va(pfn << PAGE_SHIFT),
+					 mfn_pte(mfn, PAGE_KERNEL), 0)) {
+		WARN(1, "Failed to update kernel mapping for mfn=%ld pfn=%ld\n",
+		      mfn, pfn);
+		BUG();
+	}
+}
+
+/*
+ * This function updates the p2m and m2p tables with an identity map from
+ * start_pfn to start_pfn+size and prepares remapping the underlying RAM of the
+ * original allocation at remap_pfn. The information needed for remapping is
+ * saved in the memory itself to avoid the need for allocating buffers. The
+ * complete remap information is contained in a list of MFNs each containing
+ * up to REMAP_SIZE MFNs and the start target PFN for doing the remap.
+ * This enables us to preserve the original mfn sequence while doing the
+ * remapping at a time when the memory management is capable of allocating
+ * virtual and physical memory in arbitrary amounts, see 'xen_remap_memory' and
+ * its callers.
+ */
+static void __init xen_do_set_identity_and_remap_chunk(
+        unsigned long start_pfn, unsigned long size, unsigned long remap_pfn)
+{
+	unsigned long buf = (unsigned long)&xen_remap_buf;
+	unsigned long mfn_save, mfn;
+	unsigned long ident_pfn_iter, remap_pfn_iter;
+	unsigned long ident_end_pfn = start_pfn + size;
+	unsigned long left = size;
+	unsigned int i, chunk;
+
+	WARN_ON(size == 0);
+
+	mfn_save = virt_to_mfn((void *)buf);
+
+	for (ident_pfn_iter = start_pfn, remap_pfn_iter = remap_pfn;
+	     ident_pfn_iter < ident_end_pfn;
+	     ident_pfn_iter += REMAP_SIZE, remap_pfn_iter += REMAP_SIZE) {
+		chunk = (left < REMAP_SIZE) ? left : REMAP_SIZE;
+
+		/* Map first pfn to xen_remap_buf */
+		mfn = pfn_to_mfn(ident_pfn_iter);
+		set_pte_mfn(buf, mfn, PAGE_KERNEL);
+
+		/* Save mapping information in page */
+		xen_remap_buf.next_area_mfn = xen_remap_mfn;
+		xen_remap_buf.target_pfn = remap_pfn_iter;
+		xen_remap_buf.size = chunk;
+		for (i = 0; i < chunk; i++)
+			xen_remap_buf.mfns[i] = pfn_to_mfn(ident_pfn_iter + i);
+
+		/* Put remap buf into list. */
+		xen_remap_mfn = mfn;
+
+		/* Set identity map */
+		set_phys_range_identity(ident_pfn_iter, ident_pfn_iter + chunk);
+
+		left -= chunk;
+	}
+
+	/* Restore old xen_remap_buf mapping */
+	set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
+}
+
+/*
+ * This function takes a contiguous pfn range that needs to be identity mapped
+ * and:
+ *
+ *  1) Finds a new range of pfns to use to remap based on E820 and remap_pfn.
+ *  2) Calls the do_ function to actually do the mapping/remapping work.
+ *
+ * The goal is to not allocate additional memory but to remap the existing
+ * pages. In the case of an error the underlying memory is simply released back
+ * to Xen and not remapped.
+ */
+static unsigned long __init xen_set_identity_and_remap_chunk(
+	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+	unsigned long remap_pfn)
+{
+	unsigned long pfn;
+	unsigned long i = 0;
+	unsigned long n = end_pfn - start_pfn;
+
+	if (remap_pfn == 0)
+		remap_pfn = nr_pages;
+
+	while (i < n) {
+		unsigned long cur_pfn = start_pfn + i;
+		unsigned long left = n - i;
+		unsigned long size = left;
+		unsigned long remap_range_size;
+
+		/* Do not remap pages beyond the current allocation */
+		if (cur_pfn >= nr_pages) {
+			/* Identity map remaining pages */
+			set_phys_range_identity(cur_pfn, cur_pfn + size);
+			break;
+		}
+		if (cur_pfn + size > nr_pages)
+			size = nr_pages - cur_pfn;
+
+		remap_range_size = xen_find_pfn_range(&remap_pfn);
+		if (!remap_range_size) {
+			pr_warn("Unable to find available pfn range, not remapping identity pages\n");
+			xen_set_identity_and_release_chunk(cur_pfn,
+						cur_pfn + left, nr_pages);
+			break;
+		}
+		/* Adjust size to fit in current e820 RAM region */
+		if (size > remap_range_size)
+			size = remap_range_size;
+
+		xen_do_set_identity_and_remap_chunk(cur_pfn, size, remap_pfn);
+
+		/* Update variables to reflect new mappings. */
+		i += size;
+		remap_pfn += size;
+	}
+
+	/*
+	 * If the PFNs are currently mapped, their VA mappings need to be
+	 * zapped.
+	 */
+	for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
+		(void)HYPERVISOR_update_va_mapping(
+			(unsigned long)__va(pfn << PAGE_SHIFT),
+			native_make_pte(0), 0);
+
+	return remap_pfn;
+}
+
+static unsigned long __init xen_count_remap_pages(
+	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+	unsigned long remap_pages)
+{
+	if (start_pfn >= nr_pages)
+		return remap_pages;
+
+	return remap_pages + min(end_pfn, nr_pages) - start_pfn;
+}
+
+static unsigned long __init xen_foreach_remap_area(unsigned long nr_pages,
+	unsigned long (*func)(unsigned long start_pfn, unsigned long end_pfn,
+			      unsigned long nr_pages, unsigned long last_val))
+{
+	phys_addr_t start = 0;
+	unsigned long ret_val = 0;
+	const struct e820_entry *entry = xen_e820_table.entries;
+	int i;
+
+	/*
+	 * Combine non-RAM regions and gaps until a RAM region (or the
+	 * end of the map) is reached, then call the provided function
+	 * to perform its duty on the non-RAM region.
+	 *
+	 * The combined non-RAM regions are rounded to a whole number
+	 * of pages so any partial pages are accessible via the 1:1
+	 * mapping.  This is needed for some BIOSes that put (for
+	 * example) the DMI tables in a reserved region that begins on
+	 * a non-page boundary.
+	 */
+	for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
+		phys_addr_t end = entry->addr + entry->size;
+		if (entry->type == E820_TYPE_RAM || i == xen_e820_table.nr_entries - 1) {
+			unsigned long start_pfn = PFN_DOWN(start);
+			unsigned long end_pfn = PFN_UP(end);
+
+			if (entry->type == E820_TYPE_RAM)
+				end_pfn = PFN_UP(entry->addr);
+
+			if (start_pfn < end_pfn)
+				ret_val = func(start_pfn, end_pfn, nr_pages,
+					       ret_val);
+			start = end;
+		}
+	}
+
+	return ret_val;
+}
+
+/*
+ * Remap the memory prepared in xen_do_set_identity_and_remap_chunk().
+ * The remap information (which mfn remap to which pfn) is contained in the
+ * to be remapped memory itself in a linked list anchored at xen_remap_mfn.
+ * This scheme allows to remap the different chunks in arbitrary order while
+ * the resulting mapping will be independent from the order.
+ */
+void __init xen_remap_memory(void)
+{
+	unsigned long buf = (unsigned long)&xen_remap_buf;
+	unsigned long mfn_save, pfn;
+	unsigned long remapped = 0;
+	unsigned int i;
+	unsigned long pfn_s = ~0UL;
+	unsigned long len = 0;
+
+	mfn_save = virt_to_mfn((void *)buf);
+
+	while (xen_remap_mfn != INVALID_P2M_ENTRY) {
+		/* Map the remap information */
+		set_pte_mfn(buf, xen_remap_mfn, PAGE_KERNEL);
+
+		BUG_ON(xen_remap_mfn != xen_remap_buf.mfns[0]);
+
+		pfn = xen_remap_buf.target_pfn;
+		for (i = 0; i < xen_remap_buf.size; i++) {
+			xen_update_mem_tables(pfn, xen_remap_buf.mfns[i]);
+			remapped++;
+			pfn++;
+		}
+		if (pfn_s == ~0UL || pfn == pfn_s) {
+			pfn_s = xen_remap_buf.target_pfn;
+			len += xen_remap_buf.size;
+		} else if (pfn_s + len == xen_remap_buf.target_pfn) {
+			len += xen_remap_buf.size;
+		} else {
+			xen_del_extra_mem(pfn_s, len);
+			pfn_s = xen_remap_buf.target_pfn;
+			len = xen_remap_buf.size;
+		}
+		xen_remap_mfn = xen_remap_buf.next_area_mfn;
+	}
+
+	if (pfn_s != ~0UL && len)
+		xen_del_extra_mem(pfn_s, len);
+
+	set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
+
+	pr_info("Remapped %ld page(s)\n", remapped);
+}
+
+static unsigned long __init xen_get_pages_limit(void)
+{
+	unsigned long limit;
+
+	limit = MAXMEM / PAGE_SIZE;
+	if (!xen_initial_domain() && xen_512gb_limit)
+		limit = GB(512) / PAGE_SIZE;
+
+	return limit;
+}
+
+static unsigned long __init xen_get_max_pages(void)
+{
+	unsigned long max_pages, limit;
+	domid_t domid = DOMID_SELF;
+	long ret;
+
+	limit = xen_get_pages_limit();
+	max_pages = limit;
+
+	/*
+	 * For the initial domain we use the maximum reservation as
+	 * the maximum page.
+	 *
+	 * For guest domains the current maximum reservation reflects
+	 * the current maximum rather than the static maximum. In this
+	 * case the e820 map provided to us will cover the static
+	 * maximum region.
+	 */
+	if (xen_initial_domain()) {
+		ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
+		if (ret > 0)
+			max_pages = ret;
+	}
+
+	return min(max_pages, limit);
+}
+
+static void __init xen_align_and_add_e820_region(phys_addr_t start,
+						 phys_addr_t size, int type)
+{
+	phys_addr_t end = start + size;
+
+	/* Align RAM regions to page boundaries. */
+	if (type == E820_TYPE_RAM) {
+		start = PAGE_ALIGN(start);
+		end &= ~((phys_addr_t)PAGE_SIZE - 1);
+#ifdef CONFIG_MEMORY_HOTPLUG
+		/*
+		 * Don't allow adding memory not in E820 map while booting the
+		 * system. Once the balloon driver is up it will remove that
+		 * restriction again.
+		 */
+		max_mem_size = end;
+#endif
+	}
+
+	e820__range_add(start, end - start, type);
+}
+
+static void __init xen_ignore_unusable(void)
+{
+	struct e820_entry *entry = xen_e820_table.entries;
+	unsigned int i;
+
+	for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
+		if (entry->type == E820_TYPE_UNUSABLE)
+			entry->type = E820_TYPE_RAM;
+	}
+}
+
+bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size)
+{
+	struct e820_entry *entry;
+	unsigned mapcnt;
+	phys_addr_t end;
+
+	if (!size)
+		return false;
+
+	end = start + size;
+	entry = xen_e820_table.entries;
+
+	for (mapcnt = 0; mapcnt < xen_e820_table.nr_entries; mapcnt++) {
+		if (entry->type == E820_TYPE_RAM && entry->addr <= start &&
+		    (entry->addr + entry->size) >= end)
+			return false;
+
+		entry++;
+	}
+
+	return true;
+}
+
+/*
+ * Find a free area in physical memory not yet reserved and compliant with
+ * E820 map.
+ * Used to relocate pre-allocated areas like initrd or p2m list which are in
+ * conflict with the to be used E820 map.
+ * In case no area is found, return 0. Otherwise return the physical address
+ * of the area which is already reserved for convenience.
+ */
+phys_addr_t __init xen_find_free_area(phys_addr_t size)
+{
+	unsigned mapcnt;
+	phys_addr_t addr, start;
+	struct e820_entry *entry = xen_e820_table.entries;
+
+	for (mapcnt = 0; mapcnt < xen_e820_table.nr_entries; mapcnt++, entry++) {
+		if (entry->type != E820_TYPE_RAM || entry->size < size)
+			continue;
+		start = entry->addr;
+		for (addr = start; addr < start + size; addr += PAGE_SIZE) {
+			if (!memblock_is_reserved(addr))
+				continue;
+			start = addr + PAGE_SIZE;
+			if (start + size > entry->addr + entry->size)
+				break;
+		}
+		if (addr >= start + size) {
+			memblock_reserve(start, size);
+			return start;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Like memcpy, but with physical addresses for dest and src.
+ */
+static void __init xen_phys_memcpy(phys_addr_t dest, phys_addr_t src,
+				   phys_addr_t n)
+{
+	phys_addr_t dest_off, src_off, dest_len, src_len, len;
+	void *from, *to;
+
+	while (n) {
+		dest_off = dest & ~PAGE_MASK;
+		src_off = src & ~PAGE_MASK;
+		dest_len = n;
+		if (dest_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off)
+			dest_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off;
+		src_len = n;
+		if (src_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off)
+			src_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off;
+		len = min(dest_len, src_len);
+		to = early_memremap(dest - dest_off, dest_len + dest_off);
+		from = early_memremap(src - src_off, src_len + src_off);
+		memcpy(to, from, len);
+		early_memunmap(to, dest_len + dest_off);
+		early_memunmap(from, src_len + src_off);
+		n -= len;
+		dest += len;
+		src += len;
+	}
+}
+
+/*
+ * Reserve Xen mfn_list.
+ */
+static void __init xen_reserve_xen_mfnlist(void)
+{
+	phys_addr_t start, size;
+
+	if (xen_start_info->mfn_list >= __START_KERNEL_map) {
+		start = __pa(xen_start_info->mfn_list);
+		size = PFN_ALIGN(xen_start_info->nr_pages *
+				 sizeof(unsigned long));
+	} else {
+		start = PFN_PHYS(xen_start_info->first_p2m_pfn);
+		size = PFN_PHYS(xen_start_info->nr_p2m_frames);
+	}
+
+	memblock_reserve(start, size);
+	if (!xen_is_e820_reserved(start, size))
+		return;
+
+	xen_relocate_p2m();
+	memblock_phys_free(start, size);
+}
+
+/**
+ * xen_memory_setup - Hook for machine specific memory setup.
+ **/
+char * __init xen_memory_setup(void)
+{
+	unsigned long max_pfn, pfn_s, n_pfns;
+	phys_addr_t mem_end, addr, size, chunk_size;
+	u32 type;
+	int rc;
+	struct xen_memory_map memmap;
+	unsigned long max_pages;
+	unsigned long extra_pages = 0;
+	int i;
+	int op;
+
+	xen_parse_512gb();
+	max_pfn = xen_get_pages_limit();
+	max_pfn = min(max_pfn, xen_start_info->nr_pages);
+	mem_end = PFN_PHYS(max_pfn);
+
+	memmap.nr_entries = ARRAY_SIZE(xen_e820_table.entries);
+	set_xen_guest_handle(memmap.buffer, xen_e820_table.entries);
+
+#if defined(CONFIG_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
+	xen_saved_max_mem_size = max_mem_size;
+#endif
+
+	op = xen_initial_domain() ?
+		XENMEM_machine_memory_map :
+		XENMEM_memory_map;
+	rc = HYPERVISOR_memory_op(op, &memmap);
+	if (rc == -ENOSYS) {
+		BUG_ON(xen_initial_domain());
+		memmap.nr_entries = 1;
+		xen_e820_table.entries[0].addr = 0ULL;
+		xen_e820_table.entries[0].size = mem_end;
+		/* 8MB slack (to balance backend allocations). */
+		xen_e820_table.entries[0].size += 8ULL << 20;
+		xen_e820_table.entries[0].type = E820_TYPE_RAM;
+		rc = 0;
+	}
+	BUG_ON(rc);
+	BUG_ON(memmap.nr_entries == 0);
+	xen_e820_table.nr_entries = memmap.nr_entries;
+
+	if (xen_initial_domain()) {
+		/*
+		 * Xen won't allow a 1:1 mapping to be created to UNUSABLE
+		 * regions, so if we're using the machine memory map leave the
+		 * region as RAM as it is in the pseudo-physical map.
+		 *
+		 * UNUSABLE regions in domUs are not handled and will need
+		 * a patch in the future.
+		 */
+		xen_ignore_unusable();
+
+#ifdef CONFIG_ISCSI_IBFT_FIND
+		/* Reserve 0.5 MiB to 1 MiB region so iBFT can be found */
+		xen_e820_table.entries[xen_e820_table.nr_entries].addr = IBFT_START;
+		xen_e820_table.entries[xen_e820_table.nr_entries].size = IBFT_END - IBFT_START;
+		xen_e820_table.entries[xen_e820_table.nr_entries].type = E820_TYPE_RESERVED;
+		xen_e820_table.nr_entries++;
+#endif
+	}
+
+	/* Make sure the Xen-supplied memory map is well-ordered. */
+	e820__update_table(&xen_e820_table);
+
+	max_pages = xen_get_max_pages();
+
+	/* How many extra pages do we need due to remapping? */
+	max_pages += xen_foreach_remap_area(max_pfn, xen_count_remap_pages);
+
+	if (max_pages > max_pfn)
+		extra_pages += max_pages - max_pfn;
+
+	/*
+	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
+	 * factor the base size.
+	 *
+	 * Make sure we have no memory above max_pages, as this area
+	 * isn't handled by the p2m management.
+	 */
+	extra_pages = min3(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+			   extra_pages, max_pages - max_pfn);
+	i = 0;
+	addr = xen_e820_table.entries[0].addr;
+	size = xen_e820_table.entries[0].size;
+	while (i < xen_e820_table.nr_entries) {
+		bool discard = false;
+
+		chunk_size = size;
+		type = xen_e820_table.entries[i].type;
+
+		if (type == E820_TYPE_RESERVED)
+			xen_pv_pci_possible = true;
+
+		if (type == E820_TYPE_RAM) {
+			if (addr < mem_end) {
+				chunk_size = min(size, mem_end - addr);
+			} else if (extra_pages) {
+				chunk_size = min(size, PFN_PHYS(extra_pages));
+				pfn_s = PFN_UP(addr);
+				n_pfns = PFN_DOWN(addr + chunk_size) - pfn_s;
+				extra_pages -= n_pfns;
+				xen_add_extra_mem(pfn_s, n_pfns);
+				xen_max_p2m_pfn = pfn_s + n_pfns;
+			} else
+				discard = true;
+		}
+
+		if (!discard)
+			xen_align_and_add_e820_region(addr, chunk_size, type);
+
+		addr += chunk_size;
+		size -= chunk_size;
+		if (size == 0) {
+			i++;
+			if (i < xen_e820_table.nr_entries) {
+				addr = xen_e820_table.entries[i].addr;
+				size = xen_e820_table.entries[i].size;
+			}
+		}
+	}
+
+	/*
+	 * Set the rest as identity mapped, in case PCI BARs are
+	 * located here.
+	 */
+	set_phys_range_identity(addr / PAGE_SIZE, ~0ul);
+
+	/*
+	 * In domU, the ISA region is normal, usable memory, but we
+	 * reserve ISA memory anyway because too many things poke
+	 * about in there.
+	 */
+	e820__range_add(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_TYPE_RESERVED);
+
+	e820__update_table(e820_table);
+
+	/*
+	 * Check whether the kernel itself conflicts with the target E820 map.
+	 * Failing now is better than running into weird problems later due
+	 * to relocating (and even reusing) pages with kernel text or data.
+	 */
+	if (xen_is_e820_reserved(__pa_symbol(_text),
+			__pa_symbol(__bss_stop) - __pa_symbol(_text))) {
+		xen_raw_console_write("Xen hypervisor allocated kernel memory conflicts with E820 map\n");
+		BUG();
+	}
+
+	/*
+	 * Check for a conflict of the hypervisor supplied page tables with
+	 * the target E820 map.
+	 */
+	xen_pt_check_e820();
+
+	xen_reserve_xen_mfnlist();
+
+	/* Check for a conflict of the initrd with the target E820 map. */
+	if (xen_is_e820_reserved(boot_params.hdr.ramdisk_image,
+				 boot_params.hdr.ramdisk_size)) {
+		phys_addr_t new_area, start, size;
+
+		new_area = xen_find_free_area(boot_params.hdr.ramdisk_size);
+		if (!new_area) {
+			xen_raw_console_write("Can't find new memory area for initrd needed due to E820 map conflict\n");
+			BUG();
+		}
+
+		start = boot_params.hdr.ramdisk_image;
+		size = boot_params.hdr.ramdisk_size;
+		xen_phys_memcpy(new_area, start, size);
+		pr_info("initrd moved from [mem %#010llx-%#010llx] to [mem %#010llx-%#010llx]\n",
+			start, start + size, new_area, new_area + size);
+		memblock_phys_free(start, size);
+		boot_params.hdr.ramdisk_image = new_area;
+		boot_params.ext_ramdisk_image = new_area >> 32;
+	}
+
+	/*
+	 * Set identity map on non-RAM pages and prepare remapping the
+	 * underlying RAM.
+	 */
+	xen_foreach_remap_area(max_pfn, xen_set_identity_and_remap_chunk);
+
+	pr_info("Released %ld page(s)\n", xen_released_pages);
+
+	return "Xen";
+}
+
+static int register_callback(unsigned type, const void *func)
+{
+	struct callback_register callback = {
+		.type = type,
+		.address = XEN_CALLBACK(__KERNEL_CS, func),
+		.flags = CALLBACKF_mask_events,
+	};
+
+	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
+}
+
+void xen_enable_sysenter(void)
+{
+	if (cpu_feature_enabled(X86_FEATURE_SYSENTER32) &&
+	    register_callback(CALLBACKTYPE_sysenter, xen_entry_SYSENTER_compat))
+		setup_clear_cpu_cap(X86_FEATURE_SYSENTER32);
+}
+
+void xen_enable_syscall(void)
+{
+	int ret;
+
+	ret = register_callback(CALLBACKTYPE_syscall, xen_entry_SYSCALL_64);
+	if (ret != 0) {
+		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
+		/* Pretty fatal; 64-bit userspace has no other
+		   mechanism for syscalls. */
+	}
+
+	if (cpu_feature_enabled(X86_FEATURE_SYSCALL32) &&
+	    register_callback(CALLBACKTYPE_syscall32, xen_entry_SYSCALL_compat))
+		setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
+}
+
+static void __init xen_pvmmu_arch_setup(void)
+{
+	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
+
+	if (register_callback(CALLBACKTYPE_event,
+			      xen_asm_exc_xen_hypervisor_callback) ||
+	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
+		BUG();
+
+	xen_enable_sysenter();
+	xen_enable_syscall();
+}
+
+/* This function is not called for HVM domains */
+void __init xen_arch_setup(void)
+{
+	xen_panic_handler_init();
+	xen_pvmmu_arch_setup();
+
+#ifdef CONFIG_ACPI
+	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
+		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
+		disable_acpi();
+	}
+#endif
+
+	memcpy(boot_command_line, xen_start_info->cmd_line,
+	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
+	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
+
+	/* Set up idle, making sure it calls safe_halt() pvop */
+	disable_cpuidle();
+	disable_cpufreq();
+	WARN_ON(xen_set_default_idle());
+#ifdef CONFIG_NUMA
+	numa_off = 1;
+#endif
+}