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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grant-table.c (4019B)

      1// SPDX-License-Identifier: GPL-2.0 OR MIT
      2/******************************************************************************
      3 * grant_table.c
      4 * x86 specific part
      5 *
      6 * Granting foreign access to our memory reservation.
      7 *
      8 * Copyright (c) 2005-2006, Christopher Clark
      9 * Copyright (c) 2004-2005, K A Fraser
     10 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
     11 *                    VA Linux Systems Japan. Split out x86 specific part.
     12 */
     13
     14#include <linux/sched.h>
     15#include <linux/mm.h>
     16#include <linux/slab.h>
     17#include <linux/vmalloc.h>
     18
     19#include <xen/interface/xen.h>
     20#include <xen/page.h>
     21#include <xen/grant_table.h>
     22#include <xen/xen.h>
     23
     24
     25static struct gnttab_vm_area {
     26	struct vm_struct *area;
     27	pte_t **ptes;
     28	int idx;
     29} gnttab_shared_vm_area, gnttab_status_vm_area;
     30
     31int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
     32			   unsigned long max_nr_gframes,
     33			   void **__shared)
     34{
     35	void *shared = *__shared;
     36	unsigned long addr;
     37	unsigned long i;
     38
     39	if (shared == NULL)
     40		*__shared = shared = gnttab_shared_vm_area.area->addr;
     41
     42	addr = (unsigned long)shared;
     43
     44	for (i = 0; i < nr_gframes; i++) {
     45		set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
     46			   mfn_pte(frames[i], PAGE_KERNEL));
     47		addr += PAGE_SIZE;
     48	}
     49
     50	return 0;
     51}
     52
     53int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
     54			   unsigned long max_nr_gframes,
     55			   grant_status_t **__shared)
     56{
     57	grant_status_t *shared = *__shared;
     58	unsigned long addr;
     59	unsigned long i;
     60
     61	if (shared == NULL)
     62		*__shared = shared = gnttab_status_vm_area.area->addr;
     63
     64	addr = (unsigned long)shared;
     65
     66	for (i = 0; i < nr_gframes; i++) {
     67		set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
     68			   mfn_pte(frames[i], PAGE_KERNEL));
     69		addr += PAGE_SIZE;
     70	}
     71
     72	return 0;
     73}
     74
     75void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
     76{
     77	pte_t **ptes;
     78	unsigned long addr;
     79	unsigned long i;
     80
     81	if (shared == gnttab_status_vm_area.area->addr)
     82		ptes = gnttab_status_vm_area.ptes;
     83	else
     84		ptes = gnttab_shared_vm_area.ptes;
     85
     86	addr = (unsigned long)shared;
     87
     88	for (i = 0; i < nr_gframes; i++) {
     89		set_pte_at(&init_mm, addr, ptes[i], __pte(0));
     90		addr += PAGE_SIZE;
     91	}
     92}
     93
     94static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
     95{
     96	struct gnttab_vm_area *area = data;
     97
     98	area->ptes[area->idx++] = pte;
     99	return 0;
    100}
    101
    102static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
    103{
    104	area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
    105	if (area->ptes == NULL)
    106		return -ENOMEM;
    107	area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
    108	if (!area->area)
    109		goto out_free_ptes;
    110	if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
    111			PAGE_SIZE * nr_frames, gnttab_apply, area))
    112		goto out_free_vm_area;
    113	return 0;
    114out_free_vm_area:
    115	free_vm_area(area->area);
    116out_free_ptes:
    117	kfree(area->ptes);
    118	return -ENOMEM;
    119}
    120
    121static void arch_gnttab_vfree(struct gnttab_vm_area *area)
    122{
    123	free_vm_area(area->area);
    124	kfree(area->ptes);
    125}
    126
    127int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
    128{
    129	int ret;
    130
    131	if (!xen_pv_domain())
    132		return 0;
    133
    134	ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
    135	if (ret < 0)
    136		return ret;
    137
    138	/*
    139	 * Always allocate the space for the status frames in case
    140	 * we're migrated to a host with V2 support.
    141	 */
    142	ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
    143	if (ret < 0)
    144		goto err;
    145
    146	return 0;
    147err:
    148	arch_gnttab_vfree(&gnttab_shared_vm_area);
    149	return -ENOMEM;
    150}
    151
    152#ifdef CONFIG_XEN_PVH
    153#include <xen/events.h>
    154#include <xen/xen-ops.h>
    155static int __init xen_pvh_gnttab_setup(void)
    156{
    157	if (!xen_pvh_domain())
    158		return -ENODEV;
    159
    160	xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
    161
    162	return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
    163					     &xen_auto_xlat_grant_frames.vaddr,
    164					     xen_auto_xlat_grant_frames.count);
    165}
    166/* Call it _before_ __gnttab_init as we need to initialize the
    167 * xen_auto_xlat_grant_frames first. */
    168core_initcall(xen_pvh_gnttab_setup);
    169#endif