[Crash-utility] Re: [Xen-devel] [PATCH] Support cross-bitness guest when core-dumping

This patch allows core-dumping to work on a cross-bit host/guest configuration, whereas previously that was not supported. It supports both PV and FV guests. The core file format generated by the host, needs to match that of the guest, so an alignment issue is addressed, along with the p2m frame list handling being done according to the guest size. Signed-off-by: Bruce Rogers <brogers(a)novell.com&gt;

diff -r 77476eeb8c42 tools/libxc/xc_core.c --- a/tools/libxc/xc_core.c Wed Jan 14 11:39:01 2009 +0000 +++ b/tools/libxc/xc_core.c Wed Jan 14 16:40:17 2009 -0700 @@ -57,9 +57,6 @@ /* number of pages to write at a time */ #define DUMP_INCREMENT (4 * 1024) - -/* Don't yet support cross-address-size core dump */ -#define guest_width (sizeof (unsigned long)) /* string table */ struct xc_core_strtab { @@ -240,7 +237,7 @@ xc_core_ehdr_init(Elf64_Ehdr *ehdr) ehdr->e_ident[EI_ABIVERSION] = EV_CURRENT; ehdr->e_type = ET_CORE; - ehdr->e_machine = ELF_ARCH_MACHINE; + /* e_machine will be filled in later */ ehdr->e_version = EV_CURRENT; ehdr->e_entry = 0; ehdr->e_phoff = 0; @@ -359,7 +356,8 @@ elfnote_dump_core_header( } static int -elfnote_dump_xen_version(void *args, dumpcore_rtn_t dump_rtn, int xc_handle) +elfnote_dump_xen_version(void *args, dumpcore_rtn_t dump_rtn, int xc_handle, + unsigned int guest_width) { int sts; struct elfnote elfnote; @@ -371,6 +369,12 @@ elfnote_dump_xen_version(void *args, dum elfnote.descsz = sizeof(xen_version); elfnote.type = XEN_ELFNOTE_DUMPCORE_XEN_VERSION; elfnote_fill_xen_version(xc_handle, &xen_version); + if (guest_width < sizeof(unsigned long)) + { + // 32 bit elf file format differs in pagesize's alignment + char *p = (char *)&xen_version.pagesize; + memmove(p - 4, p, sizeof(xen_version.pagesize)); + } sts = dump_rtn(args, (char*)&elfnote, sizeof(elfnote)); if ( sts != 0 ) return sts; @@ -396,6 +400,24 @@ elfnote_dump_format_version(void *args, return dump_rtn(args, (char*)&format_version, sizeof(format_version)); } +static int +get_guest_width(int xc_handle, + uint32_t domid, + unsigned int *guest_width) +{ + DECLARE_DOMCTL; + + memset(&domctl, 0, sizeof(domctl)); + domctl.domain = domid; + domctl.cmd = XEN_DOMCTL_get_address_size; + + if ( do_domctl(xc_handle, &domctl) != 0 ) + return 1; + + *guest_width = domctl.u.address_size.size / 8; + return 0; +} + int xc_domain_dumpcore_via_callback(int xc_handle, uint32_t domid, @@ -403,7 +425,8 @@ xc_domain_dumpcore_via_callback(int xc_h dumpcore_rtn_t dump_rtn) { xc_dominfo_t info; - shared_info_t *live_shinfo = NULL; + shared_info_any_t *live_shinfo = NULL; + unsigned int guest_width; int nr_vcpus = 0; char *dump_mem, *dump_mem_start = NULL; @@ -437,6 +460,12 @@ xc_domain_dumpcore_via_callback(int xc_h uint16_t strtab_idx; struct xc_core_section_headers *sheaders = NULL; Elf64_Shdr *shdr; + + if ( get_guest_width(xc_handle, domid, &guest_width) != 0 ) + { + PERROR("Could not get address size for domain"); + return sts; + } xc_core_arch_context_init(&arch_ctxt); if ( (dump_mem_start = malloc(DUMP_INCREMENT*PAGE_SIZE)) == NULL ) @@ -500,7 +529,7 @@ xc_domain_dumpcore_via_callback(int xc_h goto out; } - sts = xc_core_arch_map_p2m(xc_handle, &info, live_shinfo, + sts = xc_core_arch_map_p2m(xc_handle, guest_width, &info, live_shinfo, &p2m, &p2m_size); if ( sts != 0 ) goto out; @@ -676,6 +705,7 @@ xc_domain_dumpcore_via_callback(int xc_h /* write out elf header */ ehdr.e_shnum = sheaders->num; ehdr.e_shstrndx = strtab_idx; + ehdr.e_machine = ELF_ARCH_MACHINE; sts = dump_rtn(args, (char*)&ehdr, sizeof(ehdr)); if ( sts != 0 ) goto out; @@ -697,7 +727,7 @@ xc_domain_dumpcore_via_callback(int xc_h goto out; /* elf note section: xen version */ - sts = elfnote_dump_xen_version(args, dump_rtn, xc_handle); + sts = elfnote_dump_xen_version(args, dump_rtn, xc_handle, guest_width); if ( sts != 0 ) goto out; @@ -757,9 +787,21 @@ xc_domain_dumpcore_via_callback(int xc_h if ( !auto_translated_physmap ) { - gmfn = p2m[i]; - if ( gmfn == INVALID_P2M_ENTRY ) - continue; + if ( guest_width >= sizeof(unsigned long) ) + { + if ( guest_width == sizeof(unsigned long) ) + gmfn = p2m[i]; + else + gmfn = ((uint64_t *)p2m)[i]; + if ( gmfn == INVALID_P2M_ENTRY ) + continue; + } + else + { + gmfn = ((uint32_t *)p2m)[i]; + if ( gmfn == (uint32_t)INVALID_P2M_ENTRY ) + continue; + } p2m_array[j].pfn = i; p2m_array[j].gmfn = gmfn; @@ -802,7 +844,7 @@ copy_done: /* When live dump-mode (-L option) is specified, * guest domain may reduce memory. pad with zero pages. */ - IPRINTF("j (%ld) != nr_pages (%ld)", j , nr_pages); + IPRINTF("j (%ld) != nr_pages (%ld)", j, nr_pages); memset(dump_mem_start, 0, PAGE_SIZE); for (; j < nr_pages; j++) { sts = dump_rtn(args, dump_mem_start, PAGE_SIZE); @@ -891,7 +933,7 @@ xc_domain_dumpcore(int xc_handle, struct dump_args da; int sts; - if ( (da.fd = open(corename, O_CREAT|O_RDWR, S_IWUSR|S_IRUSR)) < 0 ) + if ( (da.fd = open(corename, O_CREAT|O_RDWR|O_TRUNC, S_IWUSR|S_IRUSR)) < 0 ) { PERROR("Could not open corefile %s", corename); return -errno; diff -r 77476eeb8c42 tools/libxc/xc_core.h --- a/tools/libxc/xc_core.h Wed Jan 14 11:39:01 2009 +0000 +++ b/tools/libxc/xc_core.h Wed Jan 14 16:40:17 2009 -0700 @@ -136,12 +136,12 @@ struct xc_core_arch_context; struct xc_core_arch_context; int xc_core_arch_memory_map_get(int xc_handle, struct xc_core_arch_context *arch_ctxt, - xc_dominfo_t *info, shared_info_t *live_shinfo, + xc_dominfo_t *info, shared_info_any_t *live_shinfo, xc_core_memory_map_t **mapp, unsigned int *nr_entries); -int xc_core_arch_map_p2m(int xc_handle, xc_dominfo_t *info, - shared_info_t *live_shinfo, xen_pfn_t **live_p2m, - unsigned long *pfnp); +int xc_core_arch_map_p2m(int xc_handle, unsigned int guest_width, + xc_dominfo_t *info, shared_info_any_t *live_shinfo, + xen_pfn_t **live_p2m, unsigned long *pfnp); #if defined (__i386__) || defined (__x86_64__) diff -r 77476eeb8c42 tools/libxc/xc_core_ia64.c --- a/tools/libxc/xc_core_ia64.c Wed Jan 14 11:39:01 2009 +0000 +++ b/tools/libxc/xc_core_ia64.c Wed Jan 14 16:40:17 2009 -0700 @@ -235,7 +235,7 @@ old: } int -xc_core_arch_map_p2m(int xc_handle, xc_dominfo_t *info, +xc_core_arch_map_p2m(int xc_handle, unsigned int guest_width, xc_dominfo_t *info, shared_info_t *live_shinfo, xen_pfn_t **live_p2m, unsigned long *pfnp) { diff -r 77476eeb8c42 tools/libxc/xc_core_x86.c --- a/tools/libxc/xc_core_x86.c Wed Jan 14 11:39:01 2009 +0000 +++ b/tools/libxc/xc_core_x86.c Wed Jan 14 16:40:17 2009 -0700 @@ -20,9 +20,25 @@ #include "xg_private.h" #include "xc_core.h" +#include "xc_e820.h" -/* Don't yet support cross-address-size core dump */ -#define guest_width (sizeof (unsigned long)) +#define GET_FIELD(_p, _f) ((guest_width==8) ? ((_p)->x64._f) : ((_p)->x32._f)) + +#ifndef MAX +#define MAX(_a, _b) ((_a) >= (_b) ? (_a) : (_b)) +#endif + +int +xc_core_arch_gpfn_may_present(struct xc_core_arch_context *arch_ctxt, + unsigned long pfn) +{ + if ((pfn >= 0xa0 && pfn < 0xc0) /* VGA hole */ + || (pfn >= (HVM_BELOW_4G_MMIO_START >> PAGE_SHIFT) + && pfn < (1ULL<<32) >> PAGE_SHIFT)) /* MMIO */ + return 0; + return 1; +} + static int nr_gpfns(int xc_handle, domid_t domid) { @@ -37,7 +53,7 @@ xc_core_arch_auto_translated_physmap(con int xc_core_arch_memory_map_get(int xc_handle, struct xc_core_arch_context *unused, - xc_dominfo_t *info, shared_info_t *live_shinfo, + xc_dominfo_t *info, shared_info_any_t *live_shinfo, xc_core_memory_map_t **mapp, unsigned int *nr_entries) { @@ -60,17 +76,22 @@ xc_core_arch_memory_map_get(int xc_handl } int -xc_core_arch_map_p2m(int xc_handle, xc_dominfo_t *info, - shared_info_t *live_shinfo, xen_pfn_t **live_p2m, +xc_core_arch_map_p2m(int xc_handle, unsigned int guest_width, xc_dominfo_t *info, + shared_info_any_t *live_shinfo, xen_pfn_t **live_p2m, unsigned long *pfnp) { /* Double and single indirect references to the live P2M table */ xen_pfn_t *live_p2m_frame_list_list = NULL; xen_pfn_t *live_p2m_frame_list = NULL; + /* Copies of the above. */ + xen_pfn_t *p2m_frame_list_list = NULL; + xen_pfn_t *p2m_frame_list = NULL; + uint32_t dom = info->domid; unsigned long p2m_size = nr_gpfns(xc_handle, info->domid); int ret = -1; int err; + int i; if ( p2m_size < info->nr_pages ) { @@ -80,7 +101,7 @@ xc_core_arch_map_p2m(int xc_handle, xc_d live_p2m_frame_list_list = xc_map_foreign_range(xc_handle, dom, PAGE_SIZE, PROT_READ, - live_shinfo->arch.pfn_to_mfn_frame_list_list); + GET_FIELD(live_shinfo, arch.pfn_to_mfn_frame_list_list)); if ( !live_p2m_frame_list_list ) { @@ -88,9 +109,28 @@ xc_core_arch_map_p2m(int xc_handle, xc_d goto out; } + /* Get a local copy of the live_P2M_frame_list_list */ + if ( !(p2m_frame_list_list = malloc(PAGE_SIZE)) ) + { + ERROR("Couldn't allocate p2m_frame_list_list array"); + goto out; + } + memcpy(p2m_frame_list_list, live_p2m_frame_list_list, PAGE_SIZE); + + /* Canonicalize guest's unsigned long vs ours */ + if ( guest_width > sizeof(unsigned long) ) + for ( i = 0; i < PAGE_SIZE/sizeof(unsigned long); i++ ) + if ( i < PAGE_SIZE/guest_width ) + p2m_frame_list_list[i] = ((uint64_t *)p2m_frame_list_list)[i]; + else + p2m_frame_list_list[i] = 0; + else if ( guest_width < sizeof(unsigned long) ) + for ( i = PAGE_SIZE/sizeof(unsigned long) - 1; i >= 0; i-- ) + p2m_frame_list_list[i] = ((uint32_t *)p2m_frame_list_list)[i]; + live_p2m_frame_list = xc_map_foreign_pages(xc_handle, dom, PROT_READ, - live_p2m_frame_list_list, + p2m_frame_list_list, P2M_FLL_ENTRIES); if ( !live_p2m_frame_list ) @@ -99,8 +139,25 @@ xc_core_arch_map_p2m(int xc_handle, xc_d goto out; } + /* Get a local copy of the live_P2M_frame_list */ + if ( !(p2m_frame_list = malloc(P2M_TOOLS_FL_SIZE)) ) + { + ERROR("Couldn't allocate p2m_frame_list array"); + goto out; + } + memset(p2m_frame_list, 0, P2M_TOOLS_FL_SIZE); + memcpy(p2m_frame_list, live_p2m_frame_list, P2M_GUEST_FL_SIZE); + + /* Canonicalize guest's unsigned long vs ours */ + if ( guest_width > sizeof(unsigned long) ) + for ( i = 0; i < P2M_FL_ENTRIES; i++ ) + p2m_frame_list[i] = ((uint64_t *)p2m_frame_list)[i]; + else if ( guest_width < sizeof(unsigned long) ) + for ( i = P2M_FL_ENTRIES - 1; i >= 0; i-- ) + p2m_frame_list[i] = ((uint32_t *)p2m_frame_list)[i]; + *live_p2m = xc_map_foreign_pages(xc_handle, dom, PROT_READ, - live_p2m_frame_list, + p2m_frame_list, P2M_FL_ENTRIES); if ( !*live_p2m ) @@ -122,6 +179,12 @@ out: if ( live_p2m_frame_list ) munmap(live_p2m_frame_list, P2M_FLL_ENTRIES * PAGE_SIZE); + if ( p2m_frame_list_list ) + free(p2m_frame_list_list); + + if ( p2m_frame_list ) + free(p2m_frame_list); + errno = err; return ret; } diff -r 77476eeb8c42 tools/libxc/xc_core_x86.h --- a/tools/libxc/xc_core_x86.h Wed Jan 14 11:39:01 2009 +0000 +++ b/tools/libxc/xc_core_x86.h Wed Jan 14 16:40:17 2009 -0700 @@ -21,15 +21,8 @@ #ifndef XC_CORE_X86_H #define XC_CORE_X86_H -#if defined(__i386__) || defined(__x86_64__) #define ELF_ARCH_DATA ELFDATA2LSB -#if defined (__i386__) -# define ELF_ARCH_MACHINE EM_386 -#else -# define ELF_ARCH_MACHINE EM_X86_64 -#endif -#endif /* __i386__ or __x86_64__ */ - +#define ELF_ARCH_MACHINE (guest_width == 8 ? EM_X86_64 : EM_386) struct xc_core_arch_context { /* nothing */ @@ -40,8 +33,10 @@ struct xc_core_arch_context { #define xc_core_arch_context_get(arch_ctxt, ctxt, xc_handle, domid) \ (0) #define xc_core_arch_context_dump(arch_ctxt, args, dump_rtn) (0) -#define xc_core_arch_gpfn_may_present(arch_ctxt, i) (1) +int +xc_core_arch_gpfn_may_present(struct xc_core_arch_context *arch_ctxt, + unsigned long pfn); static inline int xc_core_arch_context_get_shdr(struct xc_core_arch_context *arch_ctxt, struct xc_core_section_headers *sheaders,

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