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  1. 26 2月, 2008 2 次提交
    • A
      x86/lguest: fix pgdir pmd index calculation · 1ce70c4f
      由 Ahmed S. Darwish 提交于 
      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: NAhmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      1ce70c4f
    • H
      lguest: include function prototypes · cbc34973
      由 Harvey Harrison 提交于 
      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: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: "rusty@rustcorp.com.au" <rusty@rustcorp.com.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      cbc34973
  3. 30 1月, 2008 7 次提交
  5. 05 11月, 2007 2 次提交
  7. 25 10月, 2007 3 次提交
  9. 24 10月, 2007 1 次提交
  11. 23 10月, 2007 10 次提交
  13. 17 10月, 2007 3 次提交
    • H
      [x86] remove uses of magic macros for boot_params access · 30c82645
      由 H. Peter Anvin 提交于 
      Instead of using magic macros for boot_params access, simply use the
boot_params structure.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      30c82645
    • J
      paravirt: clean up lazy mode handling · 8965c1c0
      由 Jeremy Fitzhardinge 提交于 
      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: NJeremy 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
    • J
      paravirt: refactor struct paravirt_ops into smaller pv_*_ops · 93b1eab3
      由 Jeremy Fitzhardinge 提交于 
      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: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NRusty 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
  15. 13 9月, 2007 1 次提交
  17. 12 8月, 2007 1 次提交
    • A
      i386: Make patching more robust, fix paravirt issue · ab144f5e
      由 Andi Kleen 提交于 
      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: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ab144f5e
  19. 09 8月, 2007 2 次提交
    • R
      lguest: Fix Malicious Guest GDT Host Crash · 0d027c01
      由 Rusty Russell 提交于 
      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: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0d027c01
    • R
      Fix non-TSC guest clocksource lockup · 37250097
      由 Rusty Russell 提交于 
      lguest uses a host-supplied wallclock-based clocksource when the TSC
is not reliable.  As this is already in nanoseconds, I naively used a
multiplier of 1 and a shift of 0.

But update_wall_time() in its infinite wisdom decides to adjust the
clock a little (where does it think it's getting a more accurate time
from?)

It will happily tweak the multiplier... to 0, then -1.

So the "fix" is to use a shift of 22 like everyone else, and a
multiplier of 1 << 22.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      37250097
  21. 29 7月, 2007 2 次提交
  23. 27 7月, 2007 3 次提交
  25. 22 7月, 2007 1 次提交
  27. 21 7月, 2007 1 次提交
  29. 20 7月, 2007 1 次提交