Files
xen/tools/libxc/xc_linux_build.c
T
2004-06-29 18:10:39 +00:00

676 lines
21 KiB
C

/******************************************************************************
* xc_linux_build.c
*/
#include "xc_private.h"
#define ELFSIZE 32
#include "xc_elf.h"
#include <zlib.h>
#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED)
#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER)
#define round_pgup(_p) (((_p)+(PAGE_SIZE-1))&PAGE_MASK)
#define round_pgdown(_p) ((_p)&PAGE_MASK)
static int readelfimage_base_and_size(char *elfbase,
unsigned long elfsize,
unsigned long *pkernstart,
unsigned long *pkernend,
unsigned long *pkernentry);
static int loadelfimage(char *elfbase, int pmh, unsigned long *parray,
unsigned long vstart);
static long get_tot_pages(int xc_handle, u32 domid)
{
dom0_op_t op;
op.cmd = DOM0_GETDOMAININFO;
op.u.getdomaininfo.domain = (domid_t)domid;
op.u.getdomaininfo.ctxt = NULL;
return (do_dom0_op(xc_handle, &op) < 0) ?
-1 : op.u.getdomaininfo.tot_pages;
}
static int get_pfn_list(int xc_handle,
u32 domid,
unsigned long *pfn_buf,
unsigned long max_pfns)
{
dom0_op_t op;
int ret;
op.cmd = DOM0_GETMEMLIST;
op.u.getmemlist.domain = (domid_t)domid;
op.u.getmemlist.max_pfns = max_pfns;
op.u.getmemlist.buffer = pfn_buf;
if ( mlock(pfn_buf, max_pfns * sizeof(unsigned long)) != 0 )
return -1;
ret = do_dom0_op(xc_handle, &op);
(void)munlock(pfn_buf, max_pfns * sizeof(unsigned long));
return (ret < 0) ? -1 : op.u.getmemlist.num_pfns;
}
static int copy_to_domain_page(int pm_handle,
unsigned long dst_pfn,
void *src_page)
{
void *vaddr = map_pfn_writeable(pm_handle, dst_pfn);
if ( vaddr == NULL )
return -1;
memcpy(vaddr, src_page, PAGE_SIZE);
unmap_pfn(pm_handle, vaddr);
return 0;
}
static int setup_guestos(int xc_handle,
u32 dom,
char *image, unsigned long image_size,
gzFile initrd_gfd, unsigned long initrd_len,
unsigned long nr_pages,
unsigned long *pvsi, unsigned long *pvke,
full_execution_context_t *ctxt,
const char *cmdline,
unsigned long shared_info_frame,
unsigned int control_evtchn,
unsigned long flags)
{
l1_pgentry_t *vl1tab=NULL, *vl1e=NULL;
l2_pgentry_t *vl2tab=NULL, *vl2e=NULL;
unsigned long *page_array = NULL;
unsigned long l2tab;
unsigned long l1tab;
unsigned long count, i;
extended_start_info_t *start_info;
shared_info_t *shared_info;
mmu_t *mmu = NULL;
int pm_handle=-1, rc;
unsigned long nr_pt_pages;
unsigned long ppt_alloc;
unsigned long *physmap, *physmap_e, physmap_pfn;
unsigned long v_start;
unsigned long vkern_start;
unsigned long vkern_entry;
unsigned long vkern_end;
unsigned long vinitrd_start;
unsigned long vinitrd_end;
unsigned long vphysmap_start;
unsigned long vphysmap_end;
unsigned long vstartinfo_start;
unsigned long vstartinfo_end;
unsigned long vstack_start;
unsigned long vstack_end;
unsigned long vpt_start;
unsigned long vpt_end;
unsigned long v_end;
rc = readelfimage_base_and_size(image, image_size,
&vkern_start, &vkern_end, &vkern_entry);
if ( rc != 0 )
goto error_out;
/*
* Why do we need this? The number of page-table frames depends on the
* size of the bootstrap address space. But the size of the address space
* depends on the number of page-table frames (since each one is mapped
* read-only). We have a pair of simultaneous equations in two unknowns,
* which we solve by exhaustive search.
*/
for ( nr_pt_pages = 2; ; nr_pt_pages++ )
{
v_start = vkern_start & ~((1<<22)-1);
vinitrd_start = round_pgup(vkern_end);
vinitrd_end = vinitrd_start + initrd_len;
vphysmap_start = round_pgup(vinitrd_end);
vphysmap_end = vphysmap_start + (nr_pages * sizeof(unsigned long));
vpt_start = round_pgup(vphysmap_end);
vpt_end = vpt_start + (nr_pt_pages * PAGE_SIZE);
vstartinfo_start = vpt_end;
vstartinfo_end = vstartinfo_start + PAGE_SIZE;
vstack_start = vstartinfo_end;
vstack_end = vstack_start + PAGE_SIZE;
v_end = (vstack_end + (1<<22)-1) & ~((1<<22)-1);
if ( (v_end - vstack_end) < (512 << 10) )
v_end += 1 << 22; /* Add extra 4MB to get >= 512kB padding. */
if ( (((v_end - v_start) >> L2_PAGETABLE_SHIFT) + 1) <= nr_pt_pages )
break;
}
if ( (v_end - v_start) > (nr_pages * PAGE_SIZE) )
{
printf("Initial guest OS requires too much space\n"
"(%luMB is greater than %luMB limit)\n",
(v_end-v_start)>>20, (nr_pages<<PAGE_SHIFT)>>20);
goto error_out;
}
printf("VIRTUAL MEMORY ARRANGEMENT:\n"
" Loaded kernel: %08lx->%08lx\n"
" Init. ramdisk: %08lx->%08lx\n"
" Phys-Mach map: %08lx->%08lx\n"
" Page tables: %08lx->%08lx\n"
" Start info: %08lx->%08lx\n"
" Boot stack: %08lx->%08lx\n"
" TOTAL: %08lx->%08lx\n",
vkern_start, vkern_end,
vinitrd_start, vinitrd_end,
vphysmap_start, vphysmap_end,
vpt_start, vpt_end,
vstartinfo_start, vstartinfo_end,
vstack_start, vstack_end,
v_start, v_end);
printf(" ENTRY ADDRESS: %08lx\n", vkern_entry);
if ( (pm_handle = init_pfn_mapper((domid_t)dom)) < 0 )
goto error_out;
if ( (page_array = malloc(nr_pages * sizeof(unsigned long))) == NULL )
{
PERROR("Could not allocate memory");
goto error_out;
}
if ( get_pfn_list(xc_handle, dom, page_array, nr_pages) != nr_pages )
{
PERROR("Could not get the page frame list");
goto error_out;
}
loadelfimage(image, pm_handle, page_array, v_start);
/* Load the initial ramdisk image. */
if ( initrd_len != 0 )
{
for ( i = (vinitrd_start - v_start);
i < (vinitrd_end - v_start); i += PAGE_SIZE )
{
char page[PAGE_SIZE];
if ( gzread(initrd_gfd, page, PAGE_SIZE) == -1 )
{
PERROR("Error reading initrd image, could not");
goto error_out;
}
copy_to_domain_page(pm_handle,
page_array[i>>PAGE_SHIFT], page);
}
}
if ( (mmu = init_mmu_updates(xc_handle, dom)) == NULL )
goto error_out;
/* First allocate page for page dir. */
ppt_alloc = (vpt_start - v_start) >> PAGE_SHIFT;
l2tab = page_array[ppt_alloc++] << PAGE_SHIFT;
ctxt->pt_base = l2tab;
/* Initialise the page tables. */
if ( (vl2tab = map_pfn_writeable(pm_handle, l2tab >> PAGE_SHIFT)) == NULL )
goto error_out;
memset(vl2tab, 0, PAGE_SIZE);
vl2e = &vl2tab[l2_table_offset(v_start)];
for ( count = 0; count < ((v_end-v_start)>>PAGE_SHIFT); count++ )
{
if ( ((unsigned long)vl1e & (PAGE_SIZE-1)) == 0 )
{
l1tab = page_array[ppt_alloc++] << PAGE_SHIFT;
if ( vl1tab != NULL )
unmap_pfn(pm_handle, vl1tab);
if ( (vl1tab = map_pfn_writeable(pm_handle,
l1tab >> PAGE_SHIFT)) == NULL )
goto error_out;
memset(vl1tab, 0, PAGE_SIZE);
vl1e = &vl1tab[l1_table_offset(v_start + (count<<PAGE_SHIFT))];
*vl2e++ = l1tab | L2_PROT;
}
*vl1e = (page_array[count] << PAGE_SHIFT) | L1_PROT;
if ( (count >= ((vpt_start-v_start)>>PAGE_SHIFT)) &&
(count < ((vpt_end -v_start)>>PAGE_SHIFT)) )
*vl1e &= ~_PAGE_RW;
vl1e++;
}
unmap_pfn(pm_handle, vl1tab);
unmap_pfn(pm_handle, vl2tab);
/* Write the phys->machine and machine->phys table entries. */
physmap_pfn = (vphysmap_start - v_start) >> PAGE_SHIFT;
physmap = physmap_e =
map_pfn_writeable(pm_handle, page_array[physmap_pfn++]);
for ( count = 0; count < nr_pages; count++ )
{
if ( add_mmu_update(xc_handle, mmu,
(page_array[count] << PAGE_SHIFT) |
MMU_MACHPHYS_UPDATE, count) )
goto error_out;
*physmap_e++ = page_array[count];
if ( ((unsigned long)physmap_e & (PAGE_SIZE-1)) == 0 )
{
unmap_pfn(pm_handle, physmap);
physmap = physmap_e =
map_pfn_writeable(pm_handle, page_array[physmap_pfn++]);
}
}
unmap_pfn(pm_handle, physmap);
/*
* Pin down l2tab addr as page dir page - causes hypervisor to provide
* correct protection for the page
*/
if ( add_mmu_update(xc_handle, mmu,
l2tab | MMU_EXTENDED_COMMAND, MMUEXT_PIN_L2_TABLE) )
goto error_out;
start_info = map_pfn_writeable(
pm_handle, page_array[(vstartinfo_start-v_start)>>PAGE_SHIFT]);
memset(start_info, 0, sizeof(*start_info));
start_info->nr_pages = nr_pages;
start_info->shared_info = shared_info_frame << PAGE_SHIFT;
start_info->flags = flags;
start_info->pt_base = vpt_start;
start_info->nr_pt_frames = nr_pt_pages;
start_info->mfn_list = vphysmap_start;
start_info->domain_controller_evtchn = control_evtchn;
if ( initrd_len != 0 )
{
start_info->mod_start = vinitrd_start;
start_info->mod_len = initrd_len;
}
strncpy(start_info->cmd_line, cmdline, MAX_CMDLINE);
start_info->cmd_line[MAX_CMDLINE-1] = '\0';
unmap_pfn(pm_handle, start_info);
/* shared_info page starts its life empty. */
shared_info = map_pfn_writeable(pm_handle, shared_info_frame);
memset(shared_info, 0, sizeof(shared_info_t));
/* Mask all upcalls... */
for ( i = 0; i < MAX_VIRT_CPUS; i++ )
shared_info->vcpu_data[i].evtchn_upcall_mask = 1;
unmap_pfn(pm_handle, shared_info);
/* Send the page update requests down to the hypervisor. */
if ( finish_mmu_updates(xc_handle, mmu) )
goto error_out;
free(mmu);
(void)close_pfn_mapper(pm_handle);
free(page_array);
*pvsi = vstartinfo_start;
*pvke = vkern_entry;
return 0;
error_out:
if ( mmu != NULL )
free(mmu);
if ( pm_handle >= 0 )
(void)close_pfn_mapper(pm_handle);
if ( page_array != NULL )
free(page_array);
return -1;
}
static unsigned long get_filesz(int fd)
{
u16 sig;
u32 _sz = 0;
unsigned long sz;
lseek(fd, 0, SEEK_SET);
read(fd, &sig, sizeof(sig));
sz = lseek(fd, 0, SEEK_END);
if ( sig == 0x8b1f ) /* GZIP signature? */
{
lseek(fd, -4, SEEK_END);
read(fd, &_sz, 4);
sz = _sz;
}
lseek(fd, 0, SEEK_SET);
return sz;
}
static char *read_kernel_image(const char *filename, unsigned long *size)
{
int kernel_fd = -1;
gzFile kernel_gfd = NULL;
char *image = NULL;
unsigned int bytes;
if ( (kernel_fd = open(filename, O_RDONLY)) < 0 )
{
PERROR("Could not open kernel image");
goto out;
}
*size = get_filesz(kernel_fd);
if ( (kernel_gfd = gzdopen(kernel_fd, "rb")) == NULL )
{
PERROR("Could not allocate decompression state for state file");
goto out;
}
if ( (image = malloc(*size)) == NULL )
{
PERROR("Could not allocate memory for kernel image");
goto out;
}
if ( (bytes = gzread(kernel_gfd, image, *size)) != *size )
{
PERROR("Error reading kernel image, could not"
" read the whole image (%d != %ld).", bytes, *size);
free(image);
image = NULL;
}
out:
if ( kernel_gfd != NULL )
gzclose(kernel_gfd);
else if ( kernel_fd >= 0 )
close(kernel_fd);
return image;
}
int xc_linux_build(int xc_handle,
u32 domid,
const char *image_name,
const char *ramdisk_name,
const char *cmdline,
unsigned int control_evtchn,
unsigned long flags)
{
dom0_op_t launch_op, op;
int initrd_fd = -1;
gzFile initrd_gfd = NULL;
int rc, i;
full_execution_context_t st_ctxt, *ctxt = &st_ctxt;
unsigned long nr_pages;
char *image = NULL;
unsigned long image_size, initrd_size=0;
unsigned long vstartinfo_start, vkern_entry;
if ( (nr_pages = get_tot_pages(xc_handle, domid)) < 0 )
{
PERROR("Could not find total pages for domain");
goto error_out;
}
if ( (image = read_kernel_image(image_name, &image_size)) == NULL )
goto error_out;
if ( (ramdisk_name != NULL) && (strlen(ramdisk_name) != 0) )
{
if ( (initrd_fd = open(ramdisk_name, O_RDONLY)) < 0 )
{
PERROR("Could not open the initial ramdisk image");
goto error_out;
}
initrd_size = get_filesz(initrd_fd);
if ( (initrd_gfd = gzdopen(initrd_fd, "rb")) == NULL )
{
PERROR("Could not allocate decompression state for initrd");
goto error_out;
}
}
if ( mlock(&st_ctxt, sizeof(st_ctxt) ) )
{
PERROR("Unable to mlock ctxt");
return 1;
}
op.cmd = DOM0_GETDOMAININFO;
op.u.getdomaininfo.domain = (domid_t)domid;
op.u.getdomaininfo.ctxt = ctxt;
if ( (do_dom0_op(xc_handle, &op) < 0) ||
((u32)op.u.getdomaininfo.domain != domid) )
{
PERROR("Could not get info on domain");
goto error_out;
}
if ( !(op.u.getdomaininfo.flags & DOMFLAGS_PAUSED) ||
(ctxt->pt_base != 0) )
{
ERROR("Domain is already constructed");
goto error_out;
}
if ( setup_guestos(xc_handle, domid, image, image_size,
initrd_gfd, initrd_size, nr_pages,
&vstartinfo_start, &vkern_entry,
ctxt, cmdline,
op.u.getdomaininfo.shared_info_frame,
control_evtchn, flags) < 0 )
{
ERROR("Error constructing guest OS");
goto error_out;
}
if ( initrd_fd >= 0 )
close(initrd_fd);
if ( initrd_gfd )
gzclose(initrd_gfd);
if ( image != NULL )
free(image);
ctxt->flags = 0;
/*
* Initial register values:
* DS,ES,FS,GS = FLAT_GUESTOS_DS
* CS:EIP = FLAT_GUESTOS_CS:start_pc
* SS:ESP = FLAT_GUESTOS_DS:start_stack
* ESI = start_info
* [EAX,EBX,ECX,EDX,EDI,EBP are zero]
* EFLAGS = IF | 2 (bit 1 is reserved and should always be 1)
*/
ctxt->cpu_ctxt.ds = FLAT_GUESTOS_DS;
ctxt->cpu_ctxt.es = FLAT_GUESTOS_DS;
ctxt->cpu_ctxt.fs = FLAT_GUESTOS_DS;
ctxt->cpu_ctxt.gs = FLAT_GUESTOS_DS;
ctxt->cpu_ctxt.ss = FLAT_GUESTOS_DS;
ctxt->cpu_ctxt.cs = FLAT_GUESTOS_CS;
ctxt->cpu_ctxt.eip = vkern_entry;
ctxt->cpu_ctxt.esp = vstartinfo_start;
ctxt->cpu_ctxt.esi = vstartinfo_start;
ctxt->cpu_ctxt.eflags = (1<<9) | (1<<2);
/* FPU is set up to default initial state. */
memset(ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
/* Virtual IDT is empty at start-of-day. */
for ( i = 0; i < 256; i++ )
{
ctxt->trap_ctxt[i].vector = i;
ctxt->trap_ctxt[i].cs = FLAT_GUESTOS_CS;
}
ctxt->fast_trap_idx = 0;
/* No LDT. */
ctxt->ldt_ents = 0;
/* Use the default Xen-provided GDT. */
ctxt->gdt_ents = 0;
/* Ring 1 stack is the initial stack. */
ctxt->guestos_ss = FLAT_GUESTOS_DS;
ctxt->guestos_esp = vstartinfo_start;
/* No debugging. */
memset(ctxt->debugreg, 0, sizeof(ctxt->debugreg));
/* No callback handlers. */
ctxt->event_callback_cs = FLAT_GUESTOS_CS;
ctxt->event_callback_eip = 0;
ctxt->failsafe_callback_cs = FLAT_GUESTOS_CS;
ctxt->failsafe_callback_eip = 0;
memset( &launch_op, 0, sizeof(launch_op) );
launch_op.u.builddomain.domain = (domid_t)domid;
launch_op.u.builddomain.ctxt = ctxt;
launch_op.cmd = DOM0_BUILDDOMAIN;
rc = do_dom0_op(xc_handle, &launch_op);
return rc;
error_out:
if ( initrd_gfd != NULL )
gzclose(initrd_gfd);
else if ( initrd_fd >= 0 )
close(initrd_fd);
if ( image != NULL )
free(image);
return -1;
}
static inline int is_loadable_phdr(Elf_Phdr *phdr)
{
return ((phdr->p_type == PT_LOAD) &&
((phdr->p_flags & (PF_W|PF_X)) != 0));
}
static int readelfimage_base_and_size(char *elfbase,
unsigned long elfsize,
unsigned long *pkernstart,
unsigned long *pkernend,
unsigned long *pkernentry)
{
Elf_Ehdr *ehdr = (Elf_Ehdr *)elfbase;
Elf_Phdr *phdr;
Elf_Shdr *shdr;
unsigned long kernstart = ~0UL, kernend=0UL;
char *shstrtab, *guestinfo;
int h;
if ( !IS_ELF(*ehdr) )
{
ERROR("Kernel image does not have an ELF header.");
return -EINVAL;
}
if ( (ehdr->e_phoff + (ehdr->e_phnum * ehdr->e_phentsize)) > elfsize )
{
ERROR("ELF program headers extend beyond end of image.");
return -EINVAL;
}
if ( (ehdr->e_shoff + (ehdr->e_shnum * ehdr->e_shentsize)) > elfsize )
{
ERROR("ELF section headers extend beyond end of image.");
return -EINVAL;
}
/* Find the section-header strings table. */
if ( ehdr->e_shstrndx == SHN_UNDEF )
{
ERROR("ELF image has no section-header strings table (shstrtab).");
return -EINVAL;
}
shdr = (Elf_Shdr *)(elfbase + ehdr->e_shoff +
(ehdr->e_shstrndx*ehdr->e_shentsize));
shstrtab = elfbase + shdr->sh_offset;
/* Find the special '__xen_guest' section and check its contents. */
for ( h = 0; h < ehdr->e_shnum; h++ )
{
shdr = (Elf_Shdr *)(elfbase + ehdr->e_shoff + (h*ehdr->e_shentsize));
if ( strcmp(&shstrtab[shdr->sh_name], "__xen_guest") != 0 )
continue;
guestinfo = elfbase + shdr->sh_offset;
if ( (strstr(guestinfo, "GUEST_OS=linux") == NULL) ||
(strstr(guestinfo, "XEN_VER=1.3") == NULL) )
{
ERROR("Will only load Linux images built for Xen v1.3");
ERROR("Actually saw: '%s'", guestinfo);
return -EINVAL;
}
break;
}
if ( h == ehdr->e_shnum )
{
ERROR("Not a Xen-ELF image: '__xen_guest' section not found.");
return -EINVAL;
}
for ( h = 0; h < ehdr->e_phnum; h++ )
{
phdr = (Elf_Phdr *)(elfbase + ehdr->e_phoff + (h*ehdr->e_phentsize));
if ( !is_loadable_phdr(phdr) )
continue;
if ( phdr->p_vaddr < kernstart )
kernstart = phdr->p_vaddr;
if ( (phdr->p_vaddr + phdr->p_memsz) > kernend )
kernend = phdr->p_vaddr + phdr->p_memsz;
}
if ( (kernstart > kernend) ||
(ehdr->e_entry < kernstart) ||
(ehdr->e_entry > kernend) )
{
ERROR("Malformed ELF image.");
return -EINVAL;
}
*pkernstart = kernstart;
*pkernend = kernend;
*pkernentry = ehdr->e_entry;
return 0;
}
static int loadelfimage(char *elfbase, int pmh, unsigned long *parray,
unsigned long vstart)
{
Elf_Ehdr *ehdr = (Elf_Ehdr *)elfbase;
Elf_Phdr *phdr;
int h;
char *va;
unsigned long pa, done, chunksz;
for ( h = 0; h < ehdr->e_phnum; h++ )
{
phdr = (Elf_Phdr *)(elfbase + ehdr->e_phoff + (h*ehdr->e_phentsize));
if ( !is_loadable_phdr(phdr) )
continue;
for ( done = 0; done < phdr->p_filesz; done += chunksz )
{
pa = (phdr->p_vaddr + done) - vstart;
va = map_pfn_writeable(pmh, parray[pa>>PAGE_SHIFT]);
va += pa & (PAGE_SIZE-1);
chunksz = phdr->p_filesz - done;
if ( chunksz > (PAGE_SIZE - (pa & (PAGE_SIZE-1))) )
chunksz = PAGE_SIZE - (pa & (PAGE_SIZE-1));
memcpy(va, elfbase + phdr->p_offset + done, chunksz);
unmap_pfn(pmh, va);
}
for ( ; done < phdr->p_memsz; done += chunksz )
{
pa = (phdr->p_vaddr + done) - vstart;
va = map_pfn_writeable(pmh, parray[pa>>PAGE_SHIFT]);
va += pa & (PAGE_SIZE-1);
chunksz = phdr->p_memsz - done;
if ( chunksz > (PAGE_SIZE - (pa & (PAGE_SIZE-1))) )
chunksz = PAGE_SIZE - (pa & (PAGE_SIZE-1));
memset(va, 0, chunksz);
unmap_pfn(pmh, va);
}
}
return 0;
}