LXR linux/drivers/xen/mem-reservation.c

   1// SPDX-License-Identifier: GPL-2.0
   2
   3/******************************************************************************
   4 * Xen memory reservation utilities.
   5 *
   6 * Copyright (c) 2003, B Dragovic
   7 * Copyright (c) 2003-2004, M Williamson, K Fraser
   8 * Copyright (c) 2005 Dan M. Smith, IBM Corporation
   9 * Copyright (c) 2010 Daniel Kiper
  10 * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
  11 */
  12
  13#include <asm/xen/hypercall.h>
  14
  15#include <xen/interface/memory.h>
  16#include <xen/mem-reservation.h>
  17#include <linux/moduleparam.h>
  18
  19bool __read_mostly xen_scrub_pages = IS_ENABLED(CONFIG_XEN_SCRUB_PAGES_DEFAULT);
  20core_param(xen_scrub_pages, xen_scrub_pages, bool, 0);
  21
  22/*
  23 * Use one extent per PAGE_SIZE to avoid to break down the page into
  24 * multiple frame.
  25 */
  26#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
  27
  28#ifdef CONFIG_XEN_HAVE_PVMMU
  29void __xenmem_reservation_va_mapping_update(unsigned long count,
  30                                            struct page **pages,
  31                                            xen_pfn_t *frames)
  32{
  33        int i;
  34
  35        for (i = 0; i < count; i++) {
  36                struct page *page = pages[i];
  37                unsigned long pfn = page_to_pfn(page);
  38                int ret;
  39
  40                BUG_ON(!page);
  41
  42                /*
  43                 * We don't support PV MMU when Linux and Xen is using
  44                 * different page granularity.
  45                 */
  46                BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
  47
  48                set_phys_to_machine(pfn, frames[i]);
  49
  50                ret = HYPERVISOR_update_va_mapping(
  51                                (unsigned long)__va(pfn << PAGE_SHIFT),
  52                                mfn_pte(frames[i], PAGE_KERNEL), 0);
  53                BUG_ON(ret);
  54        }
  55}
  56EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
  57
  58void __xenmem_reservation_va_mapping_reset(unsigned long count,
  59                                           struct page **pages)
  60{
  61        int i;
  62
  63        for (i = 0; i < count; i++) {
  64                struct page *page = pages[i];
  65                unsigned long pfn = page_to_pfn(page);
  66                int ret;
  67
  68                /*
  69                 * We don't support PV MMU when Linux and Xen are using
  70                 * different page granularity.
  71                 */
  72                BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
  73
  74                ret = HYPERVISOR_update_va_mapping(
  75                                (unsigned long)__va(pfn << PAGE_SHIFT),
  76                                __pte_ma(0), 0);
  77                BUG_ON(ret);
  78
  79                __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
  80        }
  81}
  82EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_reset);
  83#endif /* CONFIG_XEN_HAVE_PVMMU */
  84
  85/* @frames is an array of PFNs */
  86int xenmem_reservation_increase(int count, xen_pfn_t *frames)
  87{
  88        struct xen_memory_reservation reservation = {
  89                .address_bits = 0,
  90                .extent_order = EXTENT_ORDER,
  91                .domid        = DOMID_SELF
  92        };
  93
  94        /* XENMEM_populate_physmap requires a PFN based on Xen granularity. */
  95        set_xen_guest_handle(reservation.extent_start, frames);
  96        reservation.nr_extents = count;
  97        return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
  98}
  99EXPORT_SYMBOL_GPL(xenmem_reservation_increase);
 100
 101/* @frames is an array of GFNs */
 102int xenmem_reservation_decrease(int count, xen_pfn_t *frames)
 103{
 104        struct xen_memory_reservation reservation = {
 105                .address_bits = 0,
 106                .extent_order = EXTENT_ORDER,
 107                .domid        = DOMID_SELF
 108        };
 109
 110        /* XENMEM_decrease_reservation requires a GFN */
 111        set_xen_guest_handle(reservation.extent_start, frames);
 112        reservation.nr_extents = count;
 113        return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
 114}
 115EXPORT_SYMBOL_GPL(xenmem_reservation_decrease);
 116