cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mem-reservation.c (3141B)

      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);