diff options
Diffstat (limited to 'tools/libxc/xc_linux_build.c')
| -rw-r--r-- | tools/libxc/xc_linux_build.c | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/tools/libxc/xc_linux_build.c b/tools/libxc/xc_linux_build.c new file mode 100644 index 0000000000..ceace01b00 --- /dev/null +++ b/tools/libxc/xc_linux_build.c @@ -0,0 +1,675 @@ +/****************************************************************************** + * 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; +} + |