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  1. 12 Jul, 2008 1 commit
  2. 09 Jul, 2008 1 commit
  3. 08 Jul, 2008 1 commit
  4. 31 May, 2008 1 commit
  5. 30 May, 2008 1 commit
  6. 17 Apr, 2008 1 commit
  7. 28 Mar, 2008 1 commit
  8. 10 Mar, 2008 2 commits
    • Rusty Russell's avatar
      lguest: Revert 1ce70c4f, fix real problem. · 4357bd94
      Rusty Russell authored
      Ahmed managed to crash the Host in release_pgd(), which cannot be a Guest
      bug, and indeed it wasn't.
      
      The bug was that handing a 0 as the address of the toplevel page table
      being manipulated can cause the lookup code in find_pgdir() to return
      an uninitialized cache entry (we shadow up to 4 top level page tables
      for each Guest).
      
      Commit 37cc8d7f introduced this
      behaviour in the Guest, uncovering the bug.
      
      The patch which he submitted (which removed the /4 from the index
      calculation) simply ensured that these high-indexed entries hit the
      early exit path of guest_set_pmd().  But you get lots of segfaults in
      guest userspace as the PMDs aren't being updated.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      4357bd94
    • Rusty Russell's avatar
      lguest: Sanitize the lguest clock. · 3fabc55f
      Rusty Russell authored
      Now the TSC code handles a zero return from calculate_cpu_khz(),
      lguest can simply pass through the value it gets from the Host: if
      non-zero, all the normal TSC code applies.
      
      Otherwise (or if the Host really doesn't support TSC), the clocksource
      code will fall back to the slower but reasonable lguest clock.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      3fabc55f
  9. 26 Feb, 2008 2 commits
    • Ahmed S. Darwish's avatar
      x86/lguest: fix pgdir pmd index calculation · 1ce70c4f
      Ahmed S. Darwish authored
      Hi all,
      
      Beginning from commits close to v2.6.25-rc2, running lguest always oopses
      the host kernel. Oops is at [1].
      
      Bisection led to the following commit:
      
      commit 37cc8d7f
      
          x86/early_ioremap: don't assume we're using swapper_pg_dir
      
          At the early stages of boot, before the kernel pagetable has been
          fully initialized, a Xen kernel will still be running off the
          Xen-provided pagetables rather than swapper_pg_dir[].  Therefore,
          readback cr3 to determine the base of the pagetable rather than
          assuming swapper_pg_dir[].
      
       static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
       {
      -	pgd_t *pgd = &swapper_pg_dir[pgd_index(addr)];
      +	/* Don't assume we're using swapper_pg_dir at this point */
      +	pgd_t *base = __va(read_cr3());
      +	pgd_t *pgd = &base[pgd_index(addr)];
       	pud_t *pud = pud_offset(pgd, addr);
       	pmd_t *pmd = pmd_offset(pud, addr);
      
      Trying to analyze the problem, it seems on the guest side of lguest,
      %cr3 has a different value from &swapper_pg-dir (which
      is AFAIK fine on a pravirt guest):
      
      Putting some debugging messages in early_ioremap_pmd:
      
      /* Appears 3 times */
      [    0.000000] ***************************
      [    0.000000] __va(%cr3) = c0000000, &swapper_pg_dir = c02cc000
      [    0.000000] ***************************
      
      After 8 hours of debugging and staring on lguest code, I noticed something
      strange in paravirt_ops->set_pmd hypercall invocation:
      
      static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
      {
      	*pmdp = pmdval;
      	lazy_hcall(LHCALL_SET_PMD, __pa(pmdp)&PAGE_MASK,
      		   (__pa(pmdp)&(PAGE_SIZE-1))/4, 0);
      }
      
      The first hcall parameter is global pgdir which looks fine. The second
      parameter is the pmd index in the pgdir which is suspectful.
      
      AFAIK, calculating the index of pmd does not need a divisoin over four.
      Removing the division made lguest work fine again . Patch is at [2].
      
      I am not sure why the division over four existed in the first place. It
      seems bogus, maybe the Xen patch just made the problem appear ?
      
      [2]: The patch:
      
      [PATCH] lguest: fix pgdir pmd index cacluation
      
      Remove an error in index calculation which leads to removing
      a not existing shadow page table (leading to a Null dereference).
      Signed-off-by: default avatarAhmed S. Darwish <darwish.07@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      1ce70c4f
    • Harvey Harrison's avatar
      lguest: include function prototypes · cbc34973
      Harvey Harrison authored
      Added a declaration to asm-x86/lguest.h and moved the extern arrays there
      as well.  As an alternative to including asm/lguest.h directly, an
      include could be put in linux/lguest.h
      Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
      Cc: "rusty@rustcorp.com.au" <rusty@rustcorp.com.au>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      cbc34973
  10. 30 Jan, 2008 7 commits
  11. 05 Nov, 2007 2 commits
  12. 25 Oct, 2007 3 commits
  13. 24 Oct, 2007 1 commit
  14. 23 Oct, 2007 10 commits
  15. 17 Oct, 2007 1 commit
  16. 16 Oct, 2007 2 commits
    • Jeremy Fitzhardinge's avatar
      paravirt: clean up lazy mode handling · 8965c1c0
      Jeremy Fitzhardinge authored
      Currently, the set_lazy_mode pv_op is overloaded with 5 functions:
       1. enter lazy cpu mode
       2. leave lazy cpu mode
       3. enter lazy mmu mode
       4. leave lazy mmu mode
       5. flush pending batched operations
      
      This complicates each paravirt backend, since it needs to deal with
      all the possible state transitions, handling flushing, etc. In
      particular, flushing is quite distinct from the other 4 functions, and
      seems to just cause complication.
      
      This patch removes the set_lazy_mode operation, and adds "enter" and
      "leave" lazy mode operations on mmu_ops and cpu_ops.  All the logic
      associated with enter and leaving lazy states is now in common code
      (basically BUG_ONs to make sure that no mode is current when entering
      a lazy mode, and make sure that the mode is current when leaving).
      Also, flush is handled in a common way, by simply leaving and
      re-entering the lazy mode.
      
      The result is that the Xen, lguest and VMI lazy mode implementations
      are much simpler.
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Andi Kleen <ak@suse.de>
      Cc: Zach Amsden <zach@vmware.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Avi Kivity <avi@qumranet.com>
      Cc: Anthony Liguory <aliguori@us.ibm.com>
      Cc: "Glauber de Oliveira Costa" <glommer@gmail.com>
      Cc: Jun Nakajima <jun.nakajima@intel.com>
      8965c1c0
    • Jeremy Fitzhardinge's avatar
      paravirt: refactor struct paravirt_ops into smaller pv_*_ops · 93b1eab3
      Jeremy Fitzhardinge authored
      This patch refactors the paravirt_ops structure into groups of
      functionally related ops:
      
      pv_info - random info, rather than function entrypoints
      pv_init_ops - functions used at boot time (some for module_init too)
      pv_misc_ops - lazy mode, which didn't fit well anywhere else
      pv_time_ops - time-related functions
      pv_cpu_ops - various privileged instruction ops
      pv_irq_ops - operations for managing interrupt state
      pv_apic_ops - APIC operations
      pv_mmu_ops - operations for managing pagetables
      
      There are several motivations for this:
      
      1. Some of these ops will be general to all x86, and some will be
         i386/x86-64 specific.  This makes it easier to share common stuff
         while allowing separate implementations where needed.
      
      2. At the moment we must export all of paravirt_ops, but modules only
         need selected parts of it.  This allows us to export on a case by case
         basis (and also choose which export license we want to apply).
      
      3. Functional groupings make things a bit more readable.
      
      Struct paravirt_ops is now only used as a template to generate
      patch-site identifiers, and to extract function pointers for inserting
      into jmp/calls when patching.  It is only instantiated when needed.
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Cc: Andi Kleen <ak@suse.de>
      Cc: Zach Amsden <zach@vmware.com>
      Cc: Avi Kivity <avi@qumranet.com>
      Cc: Anthony Liguory <aliguori@us.ibm.com>
      Cc: "Glauber de Oliveira Costa" <glommer@gmail.com>
      Cc: Jun Nakajima <jun.nakajima@intel.com>
      93b1eab3
  17. 12 Sep, 2007 1 commit
  18. 11 Aug, 2007 1 commit
    • Andi Kleen's avatar
      i386: Make patching more robust, fix paravirt issue · ab144f5e
      Andi Kleen authored
      Commit 19d36ccd "x86: Fix alternatives
      and kprobes to remap write-protected kernel text" uses code which is
      being patched for patching.
      
      In particular, paravirt_ops does patching in two stages: first it
      calls paravirt_ops.patch, then it fills any remaining instructions
      with nop_out().  nop_out calls text_poke() which calls
      lookup_address() which calls pgd_val() (aka paravirt_ops.pgd_val):
      that call site is one of the places we patch.
      
      If we always do patching as one single call to text_poke(), we only
      need make sure we're not patching the memcpy in text_poke itself.
      This means the prototype to paravirt_ops.patch needs to change, to
      marshal the new code into a buffer rather than patching in place as it
      does now.  It also means all patching goes through text_poke(), which
      is known to be safe (apply_alternatives is also changed to make a
      single patch).
      
      AK: fix compilation on x86-64 (bad rusty!)
      AK: fix boot on x86-64 (sigh)
      AK: merged with other patches
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarAndi Kleen <ak@suse.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ab144f5e
  19. 09 Aug, 2007 1 commit
    • Rusty Russell's avatar
      lguest: Fix Malicious Guest GDT Host Crash · 0d027c01
      Rusty Russell authored
      If a Guest makes hypercall which sets a GDT entry to not present, we
      currently set any segment registers using that GDT entry to 0.
      Unfortunately, this is not sufficient: there are other ways of
      altering GDT entries which will cause a fault.
      
      The correct solution to do what Linux does: let them set any GDT value
      they want and handle the #GP when popping causes a fault.  This has
      the added benefit of making our Switcher slightly more robust in the
      case of any other bugs which cause it to fault.
      
      We kill the Guest if it causes a fault in the Switcher: it's the
      Guest's responsibility to make sure it's not using segments when it
      changes them.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0d027c01