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  1. 01 Sep, 2011 2 commits
    • Igor Mammedov's avatar
      xen: x86_32: do not enable iterrupts when returning from exception in interrupt context · d198d499
      Igor Mammedov authored 
      If vmalloc page_fault happens inside of interrupt handler with interrupts
disabled then on exit path from exception handler when there is no pending
interrupts, the following code (arch/x86/xen/xen-asm_32.S:112):

	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
	sete XEN_vcpu_info_mask(%eax)

will enable interrupts even if they has been previously disabled according to
eflags from the bounce frame (arch/x86/xen/xen-asm_32.S:99)

	testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
	setz XEN_vcpu_info_mask(%eax)

Solution is in setting XEN_vcpu_info_mask only when it should be set
according to
	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
but not clearing it if there isn't any pending events.

Reproducer for bug is attached to RHBZ 707552

CC: stable@kernel.org
Signed-off-by: default avatarIgor Mammedov <imammedo@redhat.com>
Acked-by: default avatarJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      d198d499
    • David Vrabel's avatar
      xen: use maximum reservation to limit amount of usable RAM · d312ae87
      David Vrabel authored 
      Use the domain's maximum reservation to limit the amount of extra RAM
for the memory balloon. This reduces the size of the pages tables and
the amount of reserved low memory (which defaults to about 1/32 of the
total RAM).

On a system with 8 GiB of RAM with the domain limited to 1 GiB the
kernel reports:

Before:

Memory: 627792k/4472000k available

After:

Memory: 549740k/11132224k available

A increase of about 76 MiB (~1.5% of the unused 7 GiB).  The reserved
low memory is also reduced from 253 MiB to 32 MiB.  The total
additional usable RAM is 329 MiB.

For dom0, this requires at patch to Xen ('x86: use 'dom0_mem' to limit
the number of pages for dom0') (c/s 23790)

CC: stable@kernel.org
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      d312ae87
  3. 22 Aug, 2011 2 commits
  5. 17 Aug, 2011 1 commit
    • Jan Beulich's avatar
      xen/x86: replace order-based range checking of M2P table by linear one · ccbcdf7c
      Jan Beulich authored 
      The order-based approach is not only less efficient (requiring a shift
and a compare, typical generated code looking like this

	mov	eax, [machine_to_phys_order]
	mov	ecx, eax
	shr	ebx, cl
	test	ebx, ebx
	jnz	...

whereas a direct check requires just a compare, like in

	cmp	ebx, [machine_to_phys_nr]
	jae	...

), but also slightly dangerous in the 32-on-64 case - the element
address calculation can wrap if the next power of two boundary is
sufficiently far away from the actual upper limit of the table, and
hence can result in user space addresses being accessed (with it being
unknown what may actually be mapped there).

Additionally, the elimination of the mistaken use of fls() here (should
have been __fls()) fixes a latent issue on x86-64 that would trigger
if the code was run on a system with memory extending beyond the 44-bit
boundary.

CC: stable@kernel.org
Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
[v1: Based on Jeremy's feedback]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      ccbcdf7c
  7. 10 Aug, 2011 1 commit
    • Randy Dunlap's avatar
      xen: xen-selfballoon.c needs more header files · 30eefc95
      Randy Dunlap authored 
      Fix build errors (found when CONFIG_SYSFS is not enabled):

drivers/xen/xen-selfballoon.c:446: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:446: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
drivers/xen/xen-selfballoon.c:446: warning: parameter names (without types) in function declaration
drivers/xen/xen-selfballoon.c:485: error: expected declaration specifiers or '...' before string constant
drivers/xen/xen-selfballoon.c:485: warning: data definition has no type or storage class
drivers/xen/xen-selfballoon.c:485: warning: type defaults to 'int' in declaration of 'MODULE_LICENSE'
drivers/xen/xen-selfballoon.c:485: warning: function declaration isn't a prototype
Signed-off-by: default avatarRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      30eefc95
  9. 05 Aug, 2011 1 commit
  11. 04 Aug, 2011 3 commits
  13. 03 Aug, 2011 4 commits
  15. 30 Jul, 2011 6 commits
  17. 28 Jul, 2011 20 commits
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