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e3dd624e487c1aca1835138d3990f78af9906238
xen/tools/libs/guest/xg_offline_page.c
T
Juergen Gross e3dd624e48 tools/libxc: move libxenguest to tools/libs/guest 
tools/libxc now contains libxenguest only. Move it to tools/libs/guest.

When generating the pkg-config file for libxenguest a filter is now
required for replacing "xenctrl" by "xencontrol" in the
"Requires.private:" entry. Add this filter to tools/libs/libs.mk.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> (stubdom parts)
2020-09-09 10:57:25 +00:00

709 lines
19 KiB
C
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/******************************************************************************
* xc_offline_page.c
*
* Helper functions to offline/online one page
*
* Copyright (c) 2003, K A Fraser.
* Copyright (c) 2009, Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; If not, see <http://www.gnu.org/licenses/>.
*/
#include <inttypes.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <xc_core.h>
#include "xc_private.h"
#include "xenctrl_dom.h"
#include "xg_private.h"
#include "xg_save_restore.h"
struct pte_backup_entry
{
xen_pfn_t table_mfn;
int offset;
};
#define DEFAULT_BACKUP_COUNT 1024
struct pte_backup
{
struct pte_backup_entry *entries;
int max;
int cur;
};
static struct domain_info_context _dinfo;
static struct domain_info_context *dinfo = &_dinfo;
int xc_mark_page_online(xc_interface *xch, unsigned long start,
unsigned long end, uint32_t *status)
{
DECLARE_SYSCTL;
DECLARE_HYPERCALL_BOUNCE(status, sizeof(uint32_t)*(end - start + 1), XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
int ret = -1;
if ( !status || (end < start) )
{
errno = EINVAL;
return -1;
}
if ( xc_hypercall_bounce_pre(xch, status) )
{
ERROR("Could not bounce memory for xc_mark_page_online\n");
return -1;
}
sysctl.cmd = XEN_SYSCTL_page_offline_op;
sysctl.u.page_offline.start = start;
sysctl.u.page_offline.cmd = sysctl_page_online;
sysctl.u.page_offline.end = end;
set_xen_guest_handle(sysctl.u.page_offline.status, status);
ret = xc_sysctl(xch, &sysctl);
xc_hypercall_bounce_post(xch, status);
return ret;
}
int xc_mark_page_offline(xc_interface *xch, unsigned long start,
unsigned long end, uint32_t *status)
{
DECLARE_SYSCTL;
DECLARE_HYPERCALL_BOUNCE(status, sizeof(uint32_t)*(end - start + 1), XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
int ret = -1;
if ( !status || (end < start) )
{
errno = EINVAL;
return -1;
}
if ( xc_hypercall_bounce_pre(xch, status) )
{
ERROR("Could not bounce memory for xc_mark_page_offline");
return -1;
}
sysctl.cmd = XEN_SYSCTL_page_offline_op;
sysctl.u.page_offline.start = start;
sysctl.u.page_offline.cmd = sysctl_page_offline;
sysctl.u.page_offline.end = end;
set_xen_guest_handle(sysctl.u.page_offline.status, status);
ret = xc_sysctl(xch, &sysctl);
xc_hypercall_bounce_post(xch, status);
return ret;
}
int xc_query_page_offline_status(xc_interface *xch, unsigned long start,
unsigned long end, uint32_t *status)
{
DECLARE_SYSCTL;
DECLARE_HYPERCALL_BOUNCE(status, sizeof(uint32_t)*(end - start + 1), XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
int ret = -1;
if ( !status || (end < start) )
{
errno = EINVAL;
return -1;
}
if ( xc_hypercall_bounce_pre(xch, status) )
{
ERROR("Could not bounce memory for xc_query_page_offline_status\n");
return -1;
}
sysctl.cmd = XEN_SYSCTL_page_offline_op;
sysctl.u.page_offline.start = start;
sysctl.u.page_offline.cmd = sysctl_query_page_offline;
sysctl.u.page_offline.end = end;
set_xen_guest_handle(sysctl.u.page_offline.status, status);
ret = xc_sysctl(xch, &sysctl);
xc_hypercall_bounce_post(xch, status);
return ret;
}
/*
* There should no update to the grant when domain paused
*/
static int xc_is_page_granted_v1(xc_interface *xch, xen_pfn_t gpfn,
grant_entry_v1_t *gnttab, int gnt_num)
{
int i = 0;
if (!gnttab)
return 0;
for (i = 0; i < gnt_num; i++)
if ( ((gnttab[i].flags & GTF_type_mask) != GTF_invalid) &&
(gnttab[i].frame == gpfn) )
break;
return (i != gnt_num);
}
static int xc_is_page_granted_v2(xc_interface *xch, xen_pfn_t gpfn,
grant_entry_v2_t *gnttab, int gnt_num)
{
int i = 0;
if (!gnttab)
return 0;
for (i = 0; i < gnt_num; i++)
if ( ((gnttab[i].hdr.flags & GTF_type_mask) != GTF_invalid) &&
(gnttab[i].full_page.frame == gpfn) )
break;
return (i != gnt_num);
}
static int backup_ptes(xen_pfn_t table_mfn, int offset,
struct pte_backup *backup)
{
if (!backup)
return -EINVAL;
if (backup->max == backup->cur)
{
backup->entries = realloc(backup->entries,
backup->max * 2 * sizeof(struct pte_backup_entry));
if (backup->entries == NULL)
return -1;
else
backup->max *= 2;
}
backup->entries[backup->cur].table_mfn = table_mfn;
backup->entries[backup->cur++].offset = offset;
return 0;
}
/*
* return:
* 1 when MMU update is required
* 0 when no changes
* <0 when error happen
*/
typedef int (*pte_func)(xc_interface *xch,
uint64_t pte, uint64_t *new_pte,
unsigned long table_mfn, int table_offset,
struct pte_backup *backup,
unsigned long no_use);
static int __clear_pte(xc_interface *xch,
uint64_t pte, uint64_t *new_pte,
unsigned long table_mfn, int table_offset,
struct pte_backup *backup,
unsigned long mfn)
{
/* If no new_pte pointer, same as no changes needed */
if (!new_pte || !backup)
return -EINVAL;
if ( !(pte & _PAGE_PRESENT))
return 0;
/* XXX Check for PSE bit here */
/* Hit one entry */
if ( ((pte >> PAGE_SHIFT_X86) & MFN_MASK_X86) == mfn)
{
*new_pte = pte & ~_PAGE_PRESENT;
if (!backup_ptes(table_mfn, table_offset, backup))
return 1;
}
return 0;
}
static int __update_pte(xc_interface *xch,
uint64_t pte, uint64_t *new_pte,
unsigned long table_mfn, int table_offset,
struct pte_backup *backup,
unsigned long new_mfn)
{
int index;
if (!new_pte)
return 0;
for (index = 0; index < backup->cur; index ++)
if ( (backup->entries[index].table_mfn == table_mfn) &&
(backup->entries[index].offset == table_offset) )
break;
if (index != backup->cur)
{
if (pte & _PAGE_PRESENT)
ERROR("Page present while in backup ptes\n");
pte &= ~MFN_MASK_X86;
pte |= (new_mfn << PAGE_SHIFT_X86) | _PAGE_PRESENT;
*new_pte = pte;
return 1;
}
return 0;
}
static int change_pte(xc_interface *xch, uint32_t domid,
struct xc_domain_meminfo *minfo,
struct pte_backup *backup,
struct xc_mmu *mmu,
pte_func func,
unsigned long data)
{
int pte_num, rc;
uint64_t i;
void *content = NULL;
pte_num = PAGE_SIZE / ((minfo->pt_levels == 2) ? 4 : 8);
for (i = 0; i < minfo->p2m_size; i++)
{
xen_pfn_t table_mfn = xc_pfn_to_mfn(i, minfo->p2m_table,
minfo->guest_width);
uint64_t pte, new_pte;
int j;
if ( (table_mfn == INVALID_PFN) ||
((minfo->pfn_type[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) ==
XEN_DOMCTL_PFINFO_XTAB) )
continue;
if ( minfo->pfn_type[i] & XEN_DOMCTL_PFINFO_LTABTYPE_MASK )
{
content = xc_map_foreign_range(xch, domid, PAGE_SIZE,
PROT_READ, table_mfn);
if (!content)
goto failed;
for (j = 0; j < pte_num; j++)
{
if ( minfo->pt_levels == 2 )
pte = ((const uint32_t*)content)[j];
else
pte = ((const uint64_t*)content)[j];
rc = func(xch, pte, &new_pte, table_mfn, j, backup, data);
switch (rc)
{
case 1:
if ( xc_add_mmu_update(xch, mmu,
table_mfn << PAGE_SHIFT |
j * ( (minfo->pt_levels == 2) ?
sizeof(uint32_t): sizeof(uint64_t)) |
MMU_PT_UPDATE_PRESERVE_AD,
new_pte) )
goto failed;
break;
case 0:
break;
default:
goto failed;
}
}
munmap(content, PAGE_SIZE);
content = NULL;
}
}
if ( xc_flush_mmu_updates(xch, mmu) )
goto failed;
return 0;
failed:
/* XXX Shall we take action if we have fail to swap? */
if (content)
munmap(content, PAGE_SIZE);
return -1;
}
static int update_pte(xc_interface *xch, uint32_t domid,
struct xc_domain_meminfo *minfo,
struct pte_backup *backup,
struct xc_mmu *mmu,
unsigned long new_mfn)
{
return change_pte(xch, domid, minfo, backup, mmu,
__update_pte, new_mfn);
}
static int clear_pte(xc_interface *xch, uint32_t domid,
struct xc_domain_meminfo *minfo,
struct pte_backup *backup,
struct xc_mmu *mmu,
xen_pfn_t mfn)
{
return change_pte(xch, domid, minfo, backup, mmu,
__clear_pte, mfn);
}
/*
* Check if a page can be exchanged successfully
*/
static int is_page_exchangable(xc_interface *xch, uint32_t domid, xen_pfn_t mfn,
xc_dominfo_t *info)
{
uint32_t status;
int rc;
/* domain checking */
if ( !domid || (domid > DOMID_FIRST_RESERVED) )
{
DPRINTF("Dom0's page can't be LM");
return 0;
}
if (info->hvm)
{
DPRINTF("Currently we can only live change PV guest's page\n");
return 0;
}
/* Check if pages are offline pending or not */
rc = xc_query_page_offline_status(xch, mfn, mfn, &status);
if ( rc || !(status & PG_OFFLINE_STATUS_OFFLINE_PENDING) )
{
ERROR("Page %lx is not offline pending %x\n",
mfn, status);
return 0;
}
return 1;
}
xen_pfn_t *xc_map_m2p(xc_interface *xch,
unsigned long max_mfn,
int prot,
unsigned long *mfn0)
{
privcmd_mmap_entry_t *entries;
unsigned long m2p_chunks, m2p_size;
xen_pfn_t *m2p;
xen_pfn_t *extent_start;
int i;
m2p = NULL;
m2p_size = M2P_SIZE(max_mfn);
m2p_chunks = M2P_CHUNKS(max_mfn);
extent_start = calloc(m2p_chunks, sizeof(xen_pfn_t));
if ( !extent_start )
{
ERROR("failed to allocate space for m2p mfns");
goto err0;
}
if ( xc_machphys_mfn_list(xch, m2p_chunks, extent_start) )
{
PERROR("xc_get_m2p_mfns");
goto err1;
}
entries = calloc(m2p_chunks, sizeof(privcmd_mmap_entry_t));
if (entries == NULL)
{
ERROR("failed to allocate space for mmap entries");
goto err1;
}
for ( i = 0; i < m2p_chunks; i++ )
entries[i].mfn = extent_start[i];
m2p = xc_map_foreign_ranges(xch, DOMID_XEN,
m2p_size, prot, M2P_CHUNK_SIZE,
entries, m2p_chunks);
if (m2p == NULL)
{
PERROR("xc_mmap_foreign_ranges failed");
goto err2;
}
if (mfn0)
*mfn0 = entries[0].mfn;
err2:
free(entries);
err1:
free(extent_start);
err0:
return m2p;
}
/* The domain should be suspended when called here */
int xc_exchange_page(xc_interface *xch, uint32_t domid, xen_pfn_t mfn)
{
xc_dominfo_t info;
struct xc_domain_meminfo minfo;
struct xc_mmu *mmu = NULL;
struct pte_backup old_ptes = {NULL, 0, 0};
grant_entry_v1_t *gnttab_v1 = NULL;
grant_entry_v2_t *gnttab_v2 = NULL;
struct mmuext_op mops;
int gnt_num, unpined = 0;
void *old_p, *backup = NULL;
int rc, result = -1;
uint32_t status;
xen_pfn_t new_mfn, gpfn;
xen_pfn_t *m2p_table;
unsigned long max_mfn;
if ( xc_domain_getinfo(xch, domid, 1, &info) != 1 )
{
ERROR("Could not get domain info");
return -1;
}
if (!info.shutdown || info.shutdown_reason != SHUTDOWN_suspend)
{
errno = EINVAL;
ERROR("Can't exchange page unless domain is suspended\n");
return -1;
}
if (!is_page_exchangable(xch, domid, mfn, &info))
{
ERROR("Could not exchange page\n");
return -1;
}
/* Map M2P and obtain gpfn */
rc = xc_maximum_ram_page(xch, &max_mfn);
if ( rc || !(m2p_table = xc_map_m2p(xch, max_mfn, PROT_READ, NULL)) )
{
PERROR("Failed to map live M2P table");
return -1;
}
gpfn = m2p_table[mfn];
/* Map domain's memory information */
memset(&minfo, 0, sizeof(minfo));
if ( xc_map_domain_meminfo(xch, domid, &minfo) )
{
PERROR("Could not map domain's memory information\n");
goto failed;
}
/* For translation macros */
dinfo->guest_width = minfo.guest_width;
dinfo->p2m_size = minfo.p2m_size;
/* Don't exchange CR3 for PAE guest in PAE host environment */
if (minfo.guest_width > sizeof(long))
{
if ( (minfo.pfn_type[gpfn] & XEN_DOMCTL_PFINFO_LTABTYPE_MASK) ==
XEN_DOMCTL_PFINFO_L3TAB )
goto failed;
}
gnttab_v2 = xc_gnttab_map_table_v2(xch, domid, &gnt_num);
if (!gnttab_v2)
{
gnttab_v1 = xc_gnttab_map_table_v1(xch, domid, &gnt_num);
if (!gnttab_v1)
{
ERROR("Failed to map grant table\n");
goto failed;
}
}
if (gnttab_v1
? xc_is_page_granted_v1(xch, mfn, gnttab_v1, gnt_num)
: xc_is_page_granted_v2(xch, mfn, gnttab_v2, gnt_num))
{
ERROR("Page %lx is granted now\n", mfn);
goto failed;
}
/* allocate required data structure */
backup = malloc(PAGE_SIZE);
if (!backup)
{
ERROR("Failed to allocate backup pages pointer\n");
goto failed;
}
old_ptes.max = DEFAULT_BACKUP_COUNT;
old_ptes.entries = malloc(sizeof(struct pte_backup_entry) *
DEFAULT_BACKUP_COUNT);
if (!old_ptes.entries)
{
ERROR("Faield to allocate backup\n");
goto failed;
}
old_ptes.cur = 0;
/* Unpin the page if it is pined */
if (minfo.pfn_type[gpfn] & XEN_DOMCTL_PFINFO_LPINTAB)
{
mops.cmd = MMUEXT_UNPIN_TABLE;
mops.arg1.mfn = mfn;
if ( xc_mmuext_op(xch, &mops, 1, domid) < 0 )
{
ERROR("Failed to unpin page %lx", mfn);
goto failed;
}
mops.arg1.mfn = mfn;
unpined = 1;
}
/* backup the content */
old_p = xc_map_foreign_range(xch, domid, PAGE_SIZE,
PROT_READ, mfn);
if (!old_p)
{
ERROR("Failed to map foreign page %lx\n", mfn);
goto failed;
}
memcpy(backup, old_p, PAGE_SIZE);
munmap(old_p, PAGE_SIZE);
mmu = xc_alloc_mmu_updates(xch, domid);
if ( mmu == NULL )
{
ERROR("%s: failed at %d\n", __FUNCTION__, __LINE__);
goto failed;
}
/* Firstly update all pte to be invalid to remove the reference */
rc = clear_pte(xch, domid, &minfo, &old_ptes, mmu, mfn);
if (rc)
{
ERROR("clear pte failed\n");
goto failed;
}
rc = xc_domain_memory_exchange_pages(xch, domid,
1, 0, &mfn,
1, 0, &new_mfn);
if (rc)
{
ERROR("Exchange the page failed\n");
/* Exchange fail means there are refere to the page still */
rc = update_pte(xch, domid, &minfo, &old_ptes, mmu, mfn);
if (rc)
result = -2;
goto failed;
}
rc = update_pte(xch, domid, &minfo, &old_ptes, mmu, new_mfn);
if (rc)
{
ERROR("update pte failed guest may be broken now\n");
/* No recover action now for swap fail */
result = -2;
goto failed;
}
/* Check if pages are offlined already */
rc = xc_query_page_offline_status(xch, mfn, mfn,
&status);
if (rc)
{
ERROR("Fail to query offline status\n");
}else if ( !(status & PG_OFFLINE_STATUS_OFFLINED) )
{
ERROR("page is still online or pending\n");
goto failed;
}
else
{
void *new_p;
IPRINTF("Now page is offlined %lx\n", mfn);
/* Update the p2m table */
minfo.p2m_table[gpfn] = new_mfn;
new_p = xc_map_foreign_range(xch, domid, PAGE_SIZE,
PROT_READ|PROT_WRITE, new_mfn);
if ( new_p == NULL )
{
ERROR("failed to map new_p for copy, guest may be broken?");
goto failed;
}
memcpy(new_p, backup, PAGE_SIZE);
munmap(new_p, PAGE_SIZE);
mops.arg1.mfn = new_mfn;
result = 0;
}
failed:
if (unpined && (minfo.pfn_type[mfn] & XEN_DOMCTL_PFINFO_LPINTAB))
{
switch ( minfo.pfn_type[mfn] & XEN_DOMCTL_PFINFO_LTABTYPE_MASK )
{
case XEN_DOMCTL_PFINFO_L1TAB:
mops.cmd = MMUEXT_PIN_L1_TABLE;
break;
case XEN_DOMCTL_PFINFO_L2TAB:
mops.cmd = MMUEXT_PIN_L2_TABLE;
break;
case XEN_DOMCTL_PFINFO_L3TAB:
mops.cmd = MMUEXT_PIN_L3_TABLE;
break;
case XEN_DOMCTL_PFINFO_L4TAB:
mops.cmd = MMUEXT_PIN_L4_TABLE;
break;
default:
ERROR("Unpined for non pate table page\n");
break;
}
if ( xc_mmuext_op(xch, &mops, 1, domid) < 0 )
{
ERROR("failed to pin the mfn again\n");
result = -2;
}
}
free(mmu);
free(old_ptes.entries);
free(backup);
if (gnttab_v1)
munmap(gnttab_v1, gnt_num / (PAGE_SIZE/sizeof(grant_entry_v1_t)));
if (gnttab_v2)
munmap(gnttab_v2, gnt_num / (PAGE_SIZE/sizeof(grant_entry_v2_t)));
xc_unmap_domain_meminfo(xch, &minfo);
munmap(m2p_table, M2P_SIZE(max_mfn));
return result;
}
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