Re: [Qemu-devel] [PATCH] /proc/self/maps content is not correct for a guest

[Riku Voipio]

Hi,

The patch in patchwork doesn't apply, even with a bit of editing. You
need to send the patch to list with git send-email instead of including
the patch inline. We have docs at:

http://wiki.qemu.org/Contribute/SubmitAPatch

Also, please include the description of the patch in the commit message,
rather than just in the mail. Thus it gets included in the git history and
people can find out why the patch have been applied more easily.

The patch itself looks correct, but indeed couldn't test it yet.

Riku

On Tue, Aug 05, 2014 at 09:27:05AM +0400, Mikhail Ilin wrote:
> ping
> 
> http://patchwork.ozlabs.org/patch/374162/
> 
> On 28.07.2014 16:02, Mikhail Ilin wrote:
> >Hi,
> >
> >As it was posted earlier the output of reading /proc/self/maps is not
> >correct for a guest. There are some issues:
> >
> >https://bugs.launchpad.net/qemu/+bug/1346784
> >http://lists.nongnu.org/archive/html/qemu-devel/2014-07/msg03085.html
> >http://lists.nongnu.org/archive/html/qemu-devel/2014-07/msg02793.html
> >
> >The patch proposes: build /proc/self/maps doing a match against guest
> >memory
> >translation table and output only that map records which are valid for
> >guest
> >memory layout.
> >
> >Patches in mentioned threads are not relevant and are covered by the
> >current
> >patch.
> >
> >We did some local tests for i386, x86_64 and arm targets. The approach
> >seems correct.
> >
> >
> > From 8479d3dd00194975d7016eeecba13ddf453e9647 Mon Sep 17 00:00:00 2001
> >From: Mikhail Ilyin <address@hidden>
> >Date: Mon, 28 Jul 2014 15:40:31 +0400
> >Subject: [PATCH] Build /proc/self/maps doing a match against guest memory
> >  translation table. Output only that map records which are valid for guest
> >  memory layout.
> >
> >Signed-off-by: Mikhail Ilyin <address@hidden>
> >---
> >  include/exec/cpu-all.h |  2 ++
> >  linux-user/syscall.c   | 25 ++++++++++---------------
> >  2 files changed, 12 insertions(+), 15 deletions(-)
> >
> >diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
> >index f91581f..f9d132f 100644
> >--- a/include/exec/cpu-all.h
> >+++ b/include/exec/cpu-all.h
> >@@ -198,6 +198,8 @@ extern unsigned long reserved_va;
> >  #define RESERVED_VA 0ul
> >  #endif
> >
> >+#define GUEST_ADDR_MAX (RESERVED_VA ? RESERVED_VA : \
> >+                                    (1ul <<
> >TARGET_VIRT_ADDR_SPACE_BITS) - 1)
> >  #endif
> >
> >  /* page related stuff */
> >diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> >index a50229d..189a8c0 100644
> >--- a/linux-user/syscall.c
> >+++ b/linux-user/syscall.c
> >@@ -5092,10 +5092,8 @@ static int open_self_cmdline(void *cpu_env, int fd)
> >
> >  static int open_self_maps(void *cpu_env, int fd)
> >  {
> >-#if defined(TARGET_ARM) || defined(TARGET_M68K) ||
> >defined(TARGET_UNICORE32)
> >      CPUState *cpu = ENV_GET_CPU((CPUArchState *)cpu_env);
> >      TaskState *ts = cpu->opaque;
> >-#endif
> >      FILE *fp;
> >      char *line = NULL;
> >      size_t len = 0;
> >@@ -5118,13 +5116,18 @@ static int open_self_maps(void *cpu_env, int fd)
> >          if ((fields < 10) || (fields > 11)) {
> >              continue;
> >          }
> >-        if (!strncmp(path, "[stack]", 7)) {
> >-            continue;
> >-        }
> >-        if (h2g_valid(min) && h2g_valid(max)) {
> >+        if (h2g_valid(min)) {
> >+            int flags = page_get_flags(h2g(min));
> >+            max = h2g_valid(max - 1) ? max :
> >(uint64_t)g2h(GUEST_ADDR_MAX);
> >+            if (page_check_range(h2g(min), max - min, flags) == -1) {
> >+                continue;
> >+            }
> >+            if (h2g(min) == ts->info->stack_limit) {
> >+                pstrcpy(path, sizeof(path), "      [stack]");
> >+            }
> >              dprintf(fd, TARGET_ABI_FMT_lx "-" TARGET_ABI_FMT_lx
> >                      " %c%c%c%c %08" PRIx64 " %02x:%02x %d %s%s\n",
> >-                    h2g(min), h2g(max), flag_r, flag_w,
> >+                    h2g(min), h2g(max - 1) + 1, flag_r, flag_w,
> >                      flag_x, flag_p, offset, dev_maj, dev_min, inode,
> >                      path[0] ? "         " : "", path);
> >          }
> >@@ -5133,14 +5136,6 @@ static int open_self_maps(void *cpu_env, int fd)
> >      free(line);
> >      fclose(fp);
> >
> >-#if defined(TARGET_ARM) || defined(TARGET_M68K) ||
> >defined(TARGET_UNICORE32)
> >-    dprintf(fd, "%08llx-%08llx rw-p %08llx 00:00 0          [stack]\n",
> >-                (unsigned long long)ts->info->stack_limit,
> >-                (unsigned long long)(ts->info->start_stack +
> >-                                     (TARGET_PAGE_SIZE - 1)) &
> >TARGET_PAGE_MASK,
> >-                (unsigned long long)0);
> >-#endif
> >-
> >      return 0;
> >  }
> >