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05db6ab3e5cbe1e5d7edaf7caaa246bb97bc45ca
xen/tools/libxc/xc_hvm_build.c
T
Tim Deegan 770d1e858d Use a reserved pfn in the guest address space to store mem event rings 
This solves a long-standing issue in which the pages backing these rings were
pages belonging to dom0 user-space processes. Thus, if the process would die
unexpectedly, Xen would keep posting events to a page now belonging to some
other process.

We update all API-consumers in tree (xenpaging and xen-access).

This is an API/ABI change, so please speak up if it breaks your accumptions.

The patch touches tools, hypervisor x86/hvm bits, and hypervisor x86/mm bits.

Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Tim Deegan <tim@xen.org>
2012-03-08 16:40:05 +00:00

473 lines
16 KiB
C
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/******************************************************************************
* xc_hvm_build.c
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stddef.h>
#include <inttypes.h>
#include <stdlib.h>
#include <unistd.h>
#include <zlib.h>
#include "xg_private.h"
#include "xc_private.h"
#include <xen/foreign/x86_32.h>
#include <xen/foreign/x86_64.h>
#include <xen/hvm/hvm_info_table.h>
#include <xen/hvm/params.h>
#include <xen/hvm/e820.h>
#include <xen/libelf/libelf.h>
#define SUPERPAGE_2MB_SHIFT 9
#define SUPERPAGE_2MB_NR_PFNS (1UL << SUPERPAGE_2MB_SHIFT)
#define SUPERPAGE_1GB_SHIFT 18
#define SUPERPAGE_1GB_NR_PFNS (1UL << SUPERPAGE_1GB_SHIFT)
#define SPECIALPAGE_PAGING 0
#define SPECIALPAGE_ACCESS 1
#define SPECIALPAGE_SHARING 2
#define SPECIALPAGE_BUFIOREQ 3
#define SPECIALPAGE_XENSTORE 4
#define SPECIALPAGE_IOREQ 5
#define SPECIALPAGE_IDENT_PT 6
#define SPECIALPAGE_CONSOLE 7
#define NR_SPECIAL_PAGES 8
#define special_pfn(x) (0xff000u - NR_SPECIAL_PAGES + (x))
static void build_hvm_info(void *hvm_info_page, uint64_t mem_size,
uint64_t mmio_start, uint64_t mmio_size)
{
struct hvm_info_table *hvm_info = (struct hvm_info_table *)
(((unsigned char *)hvm_info_page) + HVM_INFO_OFFSET);
uint64_t lowmem_end = mem_size, highmem_end = 0;
uint8_t sum;
int i;
if ( lowmem_end > mmio_start )
{
highmem_end = (1ull<<32) + (lowmem_end - mmio_start);
lowmem_end = mmio_start;
}
memset(hvm_info_page, 0, PAGE_SIZE);
/* Fill in the header. */
strncpy(hvm_info->signature, "HVM INFO", 8);
hvm_info->length = sizeof(struct hvm_info_table);
/* Sensible defaults: these can be overridden by the caller. */
hvm_info->apic_mode = 1;
hvm_info->nr_vcpus = 1;
memset(hvm_info->vcpu_online, 0xff, sizeof(hvm_info->vcpu_online));
/* Memory parameters. */
hvm_info->low_mem_pgend = lowmem_end >> PAGE_SHIFT;
hvm_info->high_mem_pgend = highmem_end >> PAGE_SHIFT;
hvm_info->reserved_mem_pgstart = special_pfn(0);
/* Finish with the checksum. */
for ( i = 0, sum = 0; i < hvm_info->length; i++ )
sum += ((uint8_t *)hvm_info)[i];
hvm_info->checksum = -sum;
}
static int loadelfimage(
xc_interface *xch,
struct elf_binary *elf, uint32_t dom, unsigned long *parray)
{
privcmd_mmap_entry_t *entries = NULL;
unsigned long pfn_start = elf->pstart >> PAGE_SHIFT;
unsigned long pfn_end = (elf->pend + PAGE_SIZE - 1) >> PAGE_SHIFT;
size_t pages = pfn_end - pfn_start;
int i, rc = -1;
/* Map address space for initial elf image. */
entries = calloc(pages, sizeof(privcmd_mmap_entry_t));
if ( entries == NULL )
goto err;
for ( i = 0; i < pages; i++ )
entries[i].mfn = parray[(elf->pstart >> PAGE_SHIFT) + i];
elf->dest = xc_map_foreign_ranges(
xch, dom, pages << PAGE_SHIFT, PROT_READ | PROT_WRITE, 1 << PAGE_SHIFT,
entries, pages);
if ( elf->dest == NULL )
goto err;
elf->dest += elf->pstart & (PAGE_SIZE - 1);
/* Load the initial elf image. */
rc = elf_load_binary(elf);
if ( rc < 0 )
PERROR("Failed to load elf binary\n");
munmap(elf->dest, pages << PAGE_SHIFT);
elf->dest = NULL;
err:
free(entries);
return rc;
}
/*
* Check whether there exists mmio hole in the specified memory range.
* Returns 1 if exists, else returns 0.
*/
static int check_mmio_hole(uint64_t start, uint64_t memsize,
uint64_t mmio_start, uint64_t mmio_size)
{
if ( start + memsize <= mmio_start || start >= mmio_start + mmio_size )
return 0;
else
return 1;
}
static int setup_guest(xc_interface *xch,
uint32_t dom, const struct xc_hvm_build_args *args,
char *image, unsigned long image_size)
{
xen_pfn_t *page_array = NULL;
unsigned long i, nr_pages = args->mem_size >> PAGE_SHIFT;
unsigned long target_pages = args->mem_target >> PAGE_SHIFT;
uint64_t mmio_start = (1ull << 32) - args->mmio_size;
uint64_t mmio_size = args->mmio_size;
unsigned long entry_eip, cur_pages, cur_pfn;
void *hvm_info_page;
uint32_t *ident_pt;
struct elf_binary elf;
uint64_t v_start, v_end;
int rc;
xen_capabilities_info_t caps;
unsigned long stat_normal_pages = 0, stat_2mb_pages = 0,
stat_1gb_pages = 0;
int pod_mode = 0;
if ( nr_pages > target_pages )
pod_mode = 1;
memset(&elf, 0, sizeof(elf));
if ( elf_init(&elf, image, image_size) != 0 )
goto error_out;
xc_elf_set_logfile(xch, &elf, 1);
elf_parse_binary(&elf);
v_start = 0;
v_end = args->mem_size;
if ( xc_version(xch, XENVER_capabilities, &caps) != 0 )
{
PERROR("Could not get Xen capabilities");
goto error_out;
}
IPRINTF("VIRTUAL MEMORY ARRANGEMENT:\n"
" Loader: %016"PRIx64"->%016"PRIx64"\n"
" TOTAL: %016"PRIx64"->%016"PRIx64"\n"
" ENTRY ADDRESS: %016"PRIx64"\n",
elf.pstart, elf.pend,
v_start, v_end,
elf_uval(&elf, elf.ehdr, e_entry));
if ( (page_array = malloc(nr_pages * sizeof(xen_pfn_t))) == NULL )
{
PERROR("Could not allocate memory.");
goto error_out;
}
for ( i = 0; i < nr_pages; i++ )
page_array[i] = i;
for ( i = mmio_start >> PAGE_SHIFT; i < nr_pages; i++ )
page_array[i] += mmio_size >> PAGE_SHIFT;
/*
* Allocate memory for HVM guest, skipping VGA hole 0xA0000-0xC0000.
*
* We attempt to allocate 1GB pages if possible. It falls back on 2MB
* pages if 1GB allocation fails. 4KB pages will be used eventually if
* both fail.
*
* Under 2MB mode, we allocate pages in batches of no more than 8MB to
* ensure that we can be preempted and hence dom0 remains responsive.
*/
rc = xc_domain_populate_physmap_exact(
xch, dom, 0xa0, 0, 0, &page_array[0x00]);
cur_pages = 0xc0;
stat_normal_pages = 0xc0;
while ( (rc == 0) && (nr_pages > cur_pages) )
{
/* Clip count to maximum 1GB extent. */
unsigned long count = nr_pages - cur_pages;
unsigned long max_pages = SUPERPAGE_1GB_NR_PFNS;
if ( count > max_pages )
count = max_pages;
cur_pfn = page_array[cur_pages];
/* Take care the corner cases of super page tails */
if ( ((cur_pfn & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
(count > (-cur_pfn & (SUPERPAGE_1GB_NR_PFNS-1))) )
count = -cur_pfn & (SUPERPAGE_1GB_NR_PFNS-1);
else if ( ((count & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
(count > SUPERPAGE_1GB_NR_PFNS) )
count &= ~(SUPERPAGE_1GB_NR_PFNS - 1);
/* Attemp to allocate 1GB super page. Because in each pass we only
* allocate at most 1GB, we don't have to clip super page boundaries.
*/
if ( ((count | cur_pfn) & (SUPERPAGE_1GB_NR_PFNS - 1)) == 0 &&
/* Check if there exists MMIO hole in the 1GB memory range */
!check_mmio_hole(cur_pfn << PAGE_SHIFT,
SUPERPAGE_1GB_NR_PFNS << PAGE_SHIFT,
mmio_start, mmio_size) )
{
long done;
unsigned long nr_extents = count >> SUPERPAGE_1GB_SHIFT;
xen_pfn_t sp_extents[nr_extents];
for ( i = 0; i < nr_extents; i++ )
sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_1GB_SHIFT)];
done = xc_domain_populate_physmap(xch, dom, nr_extents, SUPERPAGE_1GB_SHIFT,
pod_mode ? XENMEMF_populate_on_demand : 0,
sp_extents);
if ( done > 0 )
{
stat_1gb_pages += done;
done <<= SUPERPAGE_1GB_SHIFT;
cur_pages += done;
count -= done;
}
}
if ( count != 0 )
{
/* Clip count to maximum 8MB extent. */
max_pages = SUPERPAGE_2MB_NR_PFNS * 4;
if ( count > max_pages )
count = max_pages;
/* Clip partial superpage extents to superpage boundaries. */
if ( ((cur_pfn & (SUPERPAGE_2MB_NR_PFNS-1)) != 0) &&
(count > (-cur_pfn & (SUPERPAGE_2MB_NR_PFNS-1))) )
count = -cur_pfn & (SUPERPAGE_2MB_NR_PFNS-1);
else if ( ((count & (SUPERPAGE_2MB_NR_PFNS-1)) != 0) &&
(count > SUPERPAGE_2MB_NR_PFNS) )
count &= ~(SUPERPAGE_2MB_NR_PFNS - 1); /* clip non-s.p. tail */
/* Attempt to allocate superpage extents. */
if ( ((count | cur_pfn) & (SUPERPAGE_2MB_NR_PFNS - 1)) == 0 )
{
long done;
unsigned long nr_extents = count >> SUPERPAGE_2MB_SHIFT;
xen_pfn_t sp_extents[nr_extents];
for ( i = 0; i < nr_extents; i++ )
sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_2MB_SHIFT)];
done = xc_domain_populate_physmap(xch, dom, nr_extents, SUPERPAGE_2MB_SHIFT,
pod_mode ? XENMEMF_populate_on_demand : 0,
sp_extents);
if ( done > 0 )
{
stat_2mb_pages += done;
done <<= SUPERPAGE_2MB_SHIFT;
cur_pages += done;
count -= done;
}
}
}
/* Fall back to 4kB extents. */
if ( count != 0 )
{
rc = xc_domain_populate_physmap_exact(
xch, dom, count, 0, 0, &page_array[cur_pages]);
cur_pages += count;
stat_normal_pages += count;
}
}
/* Subtract 0x20 from target_pages for the VGA "hole". Xen will
* adjust the PoD cache size so that domain tot_pages will be
* target_pages - 0x20 after this call. */
if ( pod_mode )
rc = xc_domain_set_pod_target(xch, dom, target_pages - 0x20,
NULL, NULL, NULL);
if ( rc != 0 )
{
PERROR("Could not allocate memory for HVM guest.");
goto error_out;
}
IPRINTF("PHYSICAL MEMORY ALLOCATION:\n"
" 4KB PAGES: 0x%016lx\n"
" 2MB PAGES: 0x%016lx\n"
" 1GB PAGES: 0x%016lx\n",
stat_normal_pages, stat_2mb_pages, stat_1gb_pages);
if ( loadelfimage(xch, &elf, dom, page_array) != 0 )
goto error_out;
if ( (hvm_info_page = xc_map_foreign_range(
xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
HVM_INFO_PFN)) == NULL )
goto error_out;
build_hvm_info(hvm_info_page, v_end, mmio_start, mmio_size);
munmap(hvm_info_page, PAGE_SIZE);
/* Allocate and clear special pages. */
for ( i = 0; i < NR_SPECIAL_PAGES; i++ )
{
xen_pfn_t pfn = special_pfn(i);
rc = xc_domain_populate_physmap_exact(xch, dom, 1, 0, 0, &pfn);
if ( rc != 0 )
{
PERROR("Could not allocate %d'th special page.", i);
goto error_out;
}
if ( xc_clear_domain_page(xch, dom, special_pfn(i)) )
goto error_out;
}
xc_set_hvm_param(xch, dom, HVM_PARAM_STORE_PFN,
special_pfn(SPECIALPAGE_XENSTORE));
xc_set_hvm_param(xch, dom, HVM_PARAM_BUFIOREQ_PFN,
special_pfn(SPECIALPAGE_BUFIOREQ));
xc_set_hvm_param(xch, dom, HVM_PARAM_IOREQ_PFN,
special_pfn(SPECIALPAGE_IOREQ));
xc_set_hvm_param(xch, dom, HVM_PARAM_CONSOLE_PFN,
special_pfn(SPECIALPAGE_CONSOLE));
xc_set_hvm_param(xch, dom, HVM_PARAM_PAGING_RING_PFN,
special_pfn(SPECIALPAGE_PAGING));
xc_set_hvm_param(xch, dom, HVM_PARAM_ACCESS_RING_PFN,
special_pfn(SPECIALPAGE_ACCESS));
xc_set_hvm_param(xch, dom, HVM_PARAM_SHARING_RING_PFN,
special_pfn(SPECIALPAGE_SHARING));
/*
* Identity-map page table is required for running with CR0.PG=0 when
* using Intel EPT. Create a 32-bit non-PAE page directory of superpages.
*/
if ( (ident_pt = xc_map_foreign_range(
xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
special_pfn(SPECIALPAGE_IDENT_PT))) == NULL )
goto error_out;
for ( i = 0; i < PAGE_SIZE / sizeof(*ident_pt); i++ )
ident_pt[i] = ((i << 22) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER |
_PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE);
munmap(ident_pt, PAGE_SIZE);
xc_set_hvm_param(xch, dom, HVM_PARAM_IDENT_PT,
special_pfn(SPECIALPAGE_IDENT_PT) << PAGE_SHIFT);
/* Insert JMP <rel32> instruction at address 0x0 to reach entry point. */
entry_eip = elf_uval(&elf, elf.ehdr, e_entry);
if ( entry_eip != 0 )
{
char *page0 = xc_map_foreign_range(
xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE, 0);
if ( page0 == NULL )
goto error_out;
page0[0] = 0xe9;
*(uint32_t *)&page0[1] = entry_eip - 5;
munmap(page0, PAGE_SIZE);
}
free(page_array);
return 0;
error_out:
free(page_array);
return -1;
}
/* xc_hvm_build:
* Create a domain for a virtualized Linux, using files/filenames.
*/
int xc_hvm_build(xc_interface *xch, uint32_t domid,
const struct xc_hvm_build_args *hvm_args)
{
struct xc_hvm_build_args args = *hvm_args;
void *image;
unsigned long image_size;
int sts;
if ( domid == 0 )
return -1;
if ( args.image_file_name == NULL )
return -1;
if ( args.mem_target == 0 )
args.mem_target = args.mem_size;
if ( args.mmio_size == 0 )
args.mmio_size = HVM_BELOW_4G_MMIO_LENGTH;
/* An HVM guest must be initialised with at least 2MB memory. */
if ( args.mem_size < (2ull << 20) || args.mem_target < (2ull << 20) )
return -1;
image = xc_read_image(xch, args.image_file_name, &image_size);
if ( image == NULL )
return -1;
sts = setup_guest(xch, domid, &args, image, image_size);
free(image);
return sts;
}
/* xc_hvm_build_target_mem:
* Create a domain for a pre-ballooned virtualized Linux, using
* files/filenames. If target < memsize, domain is created with
* memsize pages marked populate-on-demand,
* calculating pod cache size based on target.
* If target == memsize, pages are populated normally.
*/
int xc_hvm_build_target_mem(xc_interface *xch,
uint32_t domid,
int memsize,
int target,
const char *image_name)
{
struct xc_hvm_build_args args = {};
args.mem_size = (uint64_t)memsize << 20;
args.mem_target = (uint64_t)target << 20;
args.image_file_name = image_name;
return xc_hvm_build(xch, domid, &args);
}
/*
* Local variables:
* mode: C
* c-set-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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