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fbf6c4db1e48d60e50c856418eda7947b185bc2f
xen/tools/libxc/xc_hvm_build.c
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Keir Fraser 52c456a522 hvm builder: Cleaner sp_extents allocation 
We do not need more than count elements in the sp_extents array.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
2008-07-31 12:38:32 +01:00

447 lines
14 KiB
C
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/******************************************************************************
* xc_hvm_build.c
*/
#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 "xc_e820.h"
#include <xen/libelf.h>
#define SUPERPAGE_PFN_SHIFT 9
#define SUPERPAGE_NR_PFNS (1UL << SUPERPAGE_PFN_SHIFT)
#define SCRATCH_PFN 0xFFFFF
#define SPECIALPAGE_GUARD 0
#define SPECIALPAGE_BUFIOREQ 1
#define SPECIALPAGE_XENSTORE 2
#define SPECIALPAGE_IOREQ 3
#define SPECIALPAGE_IDENT_PT 4
#define NR_SPECIAL_PAGES 5
static void build_e820map(void *e820_page, unsigned long long mem_size)
{
struct e820entry *e820entry =
(struct e820entry *)(((unsigned char *)e820_page) + HVM_E820_OFFSET);
unsigned long long extra_mem_size = 0;
unsigned char nr_map = 0;
/*
* Physical address space from HVM_BELOW_4G_RAM_END to 4G is reserved
* for PCI devices MMIO. So if HVM has more than HVM_BELOW_4G_RAM_END
* RAM, memory beyond HVM_BELOW_4G_RAM_END will go to 4G above.
*/
if ( mem_size > HVM_BELOW_4G_RAM_END )
{
extra_mem_size = mem_size - HVM_BELOW_4G_RAM_END;
mem_size = HVM_BELOW_4G_RAM_END;
}
/* 0x0-0x9FC00: Ordinary RAM. */
e820entry[nr_map].addr = 0x0;
e820entry[nr_map].size = 0x9FC00;
e820entry[nr_map].type = E820_RAM;
nr_map++;
/* 0x9FC00-0xA0000: Extended BIOS Data Area (EBDA). */
e820entry[nr_map].addr = 0x9FC00;
e820entry[nr_map].size = 0x400;
e820entry[nr_map].type = E820_RESERVED;
nr_map++;
/*
* Following regions are standard regions of the PC memory map.
* They are not covered by e820 regions. OSes will not use as RAM.
* 0xA0000-0xC0000: VGA memory-mapped I/O. Not covered by E820.
* 0xC0000-0xE0000: 16-bit devices, expansion ROMs (inc. vgabios).
* TODO: hvmloader should free pages which turn out to be unused.
*/
/*
* 0xE0000-0x0F0000: PC-specific area. We place ACPI tables here.
* We *cannot* mark as E820_ACPI, for two reasons:
* 1. ACPI spec. says that E820_ACPI regions below
* 16MB must clip INT15h 0x88 and 0xe801 queries.
* Our rombios doesn't do this.
* 2. The OS is allowed to reclaim ACPI memory after
* parsing the tables. But our FACS is in this
* region and it must not be reclaimed (it contains
* the ACPI global lock!).
* 0xF0000-0x100000: System BIOS.
* TODO: hvmloader should free pages which turn out to be unused.
*/
e820entry[nr_map].addr = 0xE0000;
e820entry[nr_map].size = 0x20000;
e820entry[nr_map].type = E820_RESERVED;
nr_map++;
/* Low RAM goes here. Reserve space for special pages. */
e820entry[nr_map].addr = 0x100000;
e820entry[nr_map].size = (mem_size - 0x100000 -
PAGE_SIZE * NR_SPECIAL_PAGES);
e820entry[nr_map].type = E820_RAM;
nr_map++;
/* Explicitly reserve space for special pages (excluding guard page). */
e820entry[nr_map].addr = mem_size - PAGE_SIZE * (NR_SPECIAL_PAGES - 1);
e820entry[nr_map].size = PAGE_SIZE * (NR_SPECIAL_PAGES - 1);
e820entry[nr_map].type = E820_RESERVED;
nr_map++;
if ( extra_mem_size )
{
e820entry[nr_map].addr = (1ULL << 32);
e820entry[nr_map].size = extra_mem_size;
e820entry[nr_map].type = E820_RAM;
nr_map++;
}
*(((unsigned char *)e820_page) + HVM_E820_NR_OFFSET) = nr_map;
}
static int loadelfimage(
struct elf_binary *elf, int xch, uint32_t dom, unsigned long *parray)
{
privcmd_mmap_entry_t *entries = NULL;
size_t pages = (elf->pend - elf->pstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
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;
/* Load the initial elf image. */
elf_load_binary(elf);
rc = 0;
munmap(elf->dest, pages << PAGE_SHIFT);
elf->dest = NULL;
err:
free(entries);
return rc;
}
static int setup_guest(int xc_handle,
uint32_t dom, int memsize,
char *image, unsigned long image_size)
{
xen_pfn_t *page_array = NULL;
unsigned long i, nr_pages = (unsigned long)memsize << (20 - PAGE_SHIFT);
unsigned long special_page_nr, entry_eip, cur_pages;
struct xen_add_to_physmap xatp;
struct shared_info *shared_info;
void *e820_page;
uint32_t *ident_pt;
struct elf_binary elf;
uint64_t v_start, v_end;
int rc;
xen_capabilities_info_t caps;
/* An HVM guest must be initialised with at least 2MB memory. */
if ( memsize < 2 )
goto error_out;
if ( elf_init(&elf, image, image_size) != 0 )
goto error_out;
elf_parse_binary(&elf);
v_start = 0;
v_end = (unsigned long long)memsize << 20;
if ( xc_version(xc_handle, XENVER_capabilities, &caps) != 0 )
{
PERROR("Could not get Xen capabilities\n");
goto error_out;
}
if ( (elf.pstart & (PAGE_SIZE - 1)) != 0 )
{
PERROR("Guest OS must load to a page boundary.\n");
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.\n");
goto error_out;
}
for ( i = 0; i < nr_pages; i++ )
page_array[i] = i;
for ( i = HVM_BELOW_4G_RAM_END >> PAGE_SHIFT; i < nr_pages; i++ )
page_array[i] += HVM_BELOW_4G_MMIO_LENGTH >> PAGE_SHIFT;
/*
* Allocate memory for HVM guest, skipping VGA hole 0xA0000-0xC0000.
* 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_memory_populate_physmap(
xc_handle, dom, 0xa0, 0, 0, &page_array[0x00]);
cur_pages = 0xc0;
while ( (rc == 0) && (nr_pages > cur_pages) )
{
/* Clip count to maximum 8MB extent. */
unsigned long count = nr_pages - cur_pages;
if ( count > 2048 )
count = 2048;
/* Clip partial superpage extents to superpage boundaries. */
if ( ((cur_pages & (SUPERPAGE_NR_PFNS-1)) != 0) &&
(count > (-cur_pages & (SUPERPAGE_NR_PFNS-1))) )
count = -cur_pages & (SUPERPAGE_NR_PFNS-1); /* clip s.p. tail */
else if ( ((count & (SUPERPAGE_NR_PFNS-1)) != 0) &&
(count > SUPERPAGE_NR_PFNS) )
count &= ~(SUPERPAGE_NR_PFNS - 1); /* clip non-s.p. tail */
/* Attempt to allocate superpage extents. */
if ( ((count | cur_pages) & (SUPERPAGE_NR_PFNS - 1)) == 0 )
{
long done;
xen_pfn_t sp_extents[count >> SUPERPAGE_PFN_SHIFT];
struct xen_memory_reservation sp_req = {
.nr_extents = count >> SUPERPAGE_PFN_SHIFT,
.extent_order = SUPERPAGE_PFN_SHIFT,
.domid = dom
};
set_xen_guest_handle(sp_req.extent_start, sp_extents);
for ( i = 0; i < sp_req.nr_extents; i++ )
sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_PFN_SHIFT)];
done = xc_memory_op(xc_handle, XENMEM_populate_physmap, &sp_req);
if ( done > 0 )
{
done <<= SUPERPAGE_PFN_SHIFT;
cur_pages += done;
count -= done;
}
}
/* Fall back to 4kB extents. */
if ( count != 0 )
{
rc = xc_domain_memory_populate_physmap(
xc_handle, dom, count, 0, 0, &page_array[cur_pages]);
cur_pages += count;
}
}
if ( rc != 0 )
{
PERROR("Could not allocate memory for HVM guest.\n");
goto error_out;
}
if ( loadelfimage(&elf, xc_handle, dom, page_array) != 0 )
goto error_out;
if ( (e820_page = xc_map_foreign_range(
xc_handle, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
HVM_E820_PAGE >> PAGE_SHIFT)) == NULL )
goto error_out;
memset(e820_page, 0, PAGE_SIZE);
build_e820map(e820_page, v_end);
munmap(e820_page, PAGE_SIZE);
/* Map and initialise shared_info page. */
xatp.domid = dom;
xatp.space = XENMAPSPACE_shared_info;
xatp.idx = 0;
xatp.gpfn = SCRATCH_PFN;
if ( (xc_memory_op(xc_handle, XENMEM_add_to_physmap, &xatp) != 0) ||
((shared_info = xc_map_foreign_range(
xc_handle, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
SCRATCH_PFN)) == NULL) )
goto error_out;
memset(shared_info, 0, PAGE_SIZE);
/* NB. evtchn_upcall_mask is unused: leave as zero. */
memset(&shared_info->evtchn_mask[0], 0xff,
sizeof(shared_info->evtchn_mask));
munmap(shared_info, PAGE_SIZE);
special_page_nr = (((v_end > HVM_BELOW_4G_RAM_END)
? (HVM_BELOW_4G_RAM_END >> PAGE_SHIFT)
: (v_end >> PAGE_SHIFT))
- NR_SPECIAL_PAGES);
/* Paranoia: clean special pages. */
for ( i = 0; i < NR_SPECIAL_PAGES; i++ )
if ( xc_clear_domain_page(xc_handle, dom, special_page_nr + i) )
goto error_out;
/* Free the guard page that separates low RAM from special pages. */
rc = xc_domain_memory_decrease_reservation(
xc_handle, dom, 1, 0, &page_array[special_page_nr]);
if ( rc != 0 )
{
PERROR("Could not deallocate guard page for HVM guest.\n");
goto error_out;
}
xc_set_hvm_param(xc_handle, dom, HVM_PARAM_STORE_PFN,
special_page_nr + SPECIALPAGE_XENSTORE);
xc_set_hvm_param(xc_handle, dom, HVM_PARAM_BUFIOREQ_PFN,
special_page_nr + SPECIALPAGE_BUFIOREQ);
xc_set_hvm_param(xc_handle, dom, HVM_PARAM_IOREQ_PFN,
special_page_nr + SPECIALPAGE_IOREQ);
/*
* 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(
xc_handle, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
special_page_nr + 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(xc_handle, dom, HVM_PARAM_IDENT_PT,
(special_page_nr + 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(
xc_handle, 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;
}
static int xc_hvm_build_internal(int xc_handle,
uint32_t domid,
int memsize,
char *image,
unsigned long image_size)
{
if ( (image == NULL) || (image_size == 0) )
{
ERROR("Image required");
return -1;
}
return setup_guest(xc_handle, domid, memsize, image, image_size);
}
static inline int is_loadable_phdr(Elf32_Phdr *phdr)
{
return ((phdr->p_type == PT_LOAD) &&
((phdr->p_flags & (PF_W|PF_X)) != 0));
}
/* xc_hvm_build:
* Create a domain for a virtualized Linux, using files/filenames.
*/
int xc_hvm_build(int xc_handle,
uint32_t domid,
int memsize,
const char *image_name)
{
char *image;
int sts;
unsigned long image_size;
if ( (image_name == NULL) ||
((image = xc_read_image(image_name, &image_size)) == NULL) )
return -1;
sts = xc_hvm_build_internal(xc_handle, domid, memsize, image, image_size);
free(image);
return sts;
}
/* xc_hvm_build_mem:
* Create a domain for a virtualized Linux, using memory buffers.
*/
int xc_hvm_build_mem(int xc_handle,
uint32_t domid,
int memsize,
const char *image_buffer,
unsigned long image_size)
{
int sts;
unsigned long img_len;
char *img;
/* Validate that there is a kernel buffer */
if ( (image_buffer == NULL) || (image_size == 0) )
{
ERROR("kernel image buffer not present");
return -1;
}
img = xc_inflate_buffer(image_buffer, image_size, &img_len);
if ( img == NULL )
{
ERROR("unable to inflate ram disk buffer");
return -1;
}
sts = xc_hvm_build_internal(xc_handle, domid, memsize,
img, img_len);
/* xc_inflate_buffer may return the original buffer pointer (for
for already inflated buffers), so exercise some care in freeing */
if ( (img != NULL) && (img != image_buffer) )
free(img);
return sts;
}
/*
* Local variables:
* mode: C
* c-set-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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