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  1. 26 2月, 2008 4 次提交
    • I
      x86: make DEBUG_PAGEALLOC and CPA more robust · 92cb54a3
      由 Ingo Molnar 提交于 
      Use PF_MEMALLOC to prevent recursive calls in the DBEUG_PAGEALLOC
case. This makes the code simpler and more robust against allocation
failures.

This fixes the following fallback to non-mmconfig:

   http://lkml.org/lkml/2008/2/20/551
   http://bugzilla.kernel.org/show_bug.cgi?id=10083

Also, for DEBUG_PAGEALLOC=n reduce the pool size to one page.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      92cb54a3
    • 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
    • T
      lguest: fix build breakage · db342d21
      由 Tony Breeds 提交于 
      [ mingo@elte.hu: merged to Rusty's patch ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      db342d21
    • 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. 25 2月, 2008 8 次提交
  5. 24 2月, 2008 28 次提交