libxc: 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@novell.com>

diff --git a/tools/libxc/xc_core.c b/tools/libxc/xc_core.c
index 9ee39810409be150753e2b3d1035886137a972e8..a7fd1647f3881d082773f6405ffb4c6e9497152a 100644 (file)
--- a/tools/libxc/xc_core.c
+++ b/tools/libxc/xc_core.c
@@ -58,9 +58,6 @@
 /* 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 {
     char       *strings;
@@ -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, dumpcore_rtn_t dump_rtn, int xc_handle)
     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, dumpcore_rtn_t dump_rtn)
     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_handle,
                                 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_handle,
     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_handle,
             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_handle,
     /* 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_handle,
         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_handle,
 
             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 --git a/tools/libxc/xc_core.h b/tools/libxc/xc_core.h
index 30100ba416b8c22c8661e3aac10aa18e1a47cf51..d148732f13dd69d5abb8f1d14ebb24f69ea4c495 100644 (file)
--- a/tools/libxc/xc_core.h
+++ b/tools/libxc/xc_core.h
@@ -136,12 +136,12 @@ int xc_core_arch_auto_translated_physmap(const xc_dominfo_t *info);
 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 --git a/tools/libxc/xc_core_ia64.c b/tools/libxc/xc_core_ia64.c
index 23e886ebbfd502bc0c6ff5419573aef359823e4b..76827e2487dea7a6c64ad67a8c31877ae80f6821 100644 (file)
--- a/tools/libxc/xc_core_ia64.c
+++ b/tools/libxc/xc_core_ia64.c
@@ -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 --git a/tools/libxc/xc_core_x86.c b/tools/libxc/xc_core_x86.c
index d9eaa49b975816b7f4b2048c8e7ed876ec2450c8..765c745cb6d8c80f2d4b7796e158fa4d6bc6c1f8 100644 (file)
--- a/tools/libxc/xc_core_x86.c
+++ b/tools/libxc/xc_core_x86.c
@@ -20,9 +20,25 @@
 
 #include "xg_private.h"
 #include "xc_core.h"
+#include "xc_e820.h"
+
+#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;
+}
 
-/* Don't yet support cross-address-size core dump */
-#define guest_width (sizeof (unsigned long))
 
 static int nr_gpfns(int xc_handle, domid_t domid)
 {
@@ -37,7 +53,7 @@ xc_core_arch_auto_translated_physmap(const xc_dominfo_t *info)
 
 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_handle, struct xc_core_arch_context *unused,
 }
 
 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_dominfo_t *info,
 
     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_dominfo_t *info,
         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_dominfo_t *info,
         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 --git a/tools/libxc/xc_core_x86.h b/tools/libxc/xc_core_x86.h
index 6e3490bb275cfc12c8e50dd031f713e2a5da304d..739d90ef290ded7b35fd587230091cf49a7cb812 100644 (file)
--- a/tools/libxc/xc_core_x86.h
+++ b/tools/libxc/xc_core_x86.h
@@ -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,