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  1. 27 2月, 2015 1 次提交
  3. 28 1月, 2015 4 次提交
  5. 19 1月, 2015 1 次提交
  7. 12 1月, 2015 2 次提交
  9. 08 1月, 2015 1 次提交
  11. 08 12月, 2014 1 次提交
  13. 04 12月, 2014 9 次提交
  15. 23 10月, 2014 3 次提交
    • J
      x86/xen: avoid race in p2m handling · 3a0e94f8
      由 Juergen Gross 提交于 
      When a new p2m leaf is allocated this leaf is linked into the p2m tree
via cmpxchg. Unfortunately the compare value for checking the success
of the update is read after checking for the need of a new leaf. It is
possible that a new leaf has been linked into the tree concurrently
in between. This could lead to a leaked memory page and to the loss of
some p2m entries.

Avoid the race by using the read compare value for checking the need
of a new p2m leaf and use ACCESS_ONCE() to get it.

There are other places which seem to need ACCESS_ONCE() to ensure
proper operation. Change them accordingly.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
      3a0e94f8
    • J
      x86/xen: delay construction of mfn_list_list · 2c185687
      由 Juergen Gross 提交于 
      The 3 level p2m tree for the Xen tools is constructed very early at
boot by calling xen_build_mfn_list_list(). Memory needed for this tree
is allocated via extend_brk().

As this tree (other than the kernel internal p2m tree) is only needed
for domain save/restore, live migration and crash dump analysis it
doesn't matter whether it is constructed very early or just some
milliseconds later when memory allocation is possible by other means.

This patch moves the call of xen_build_mfn_list_list() just after
calling xen_pagetable_p2m_copy() simplifying this function, too, as it
doesn't have to bother with two parallel trees now. The same applies
for some other internal functions.

While simplifying code, make early_can_reuse_p2m_middle() static and
drop the unused second parameter. p2m_mid_identity_mfn can be removed
as well, it isn't used either.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
      2c185687
    • J
      x86/xen: avoid writing to freed memory after race in p2m handling · 239af7c7
      由 Juergen Gross 提交于 
      In case a race was detected during allocation of a new p2m tree
element in alloc_p2m() the new allocated mid_mfn page is freed without
updating the pointer to the found value in the tree. This will result
in overwriting the just freed page with the mfn of the p2m leaf.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
      239af7c7
  17. 23 9月, 2014 1 次提交
    • M
      xen/setup: Remap Xen Identity Mapped RAM · 4fbb67e3
      由 Matt Rushton 提交于 
      Instead of ballooning up and down dom0 memory this remaps the existing mfns
that were replaced by the identity map. The reason for this is that the
existing implementation ballooned memory up and and down which caused dom0
to have discontiguous pages. In some cases this resulted in the use of bounce
buffers which reduced network I/O performance significantly. This change will
honor the existing order of the pages with the exception of some boundary
conditions.

To do this we need to update both the Linux p2m table and the Xen m2p table.
Particular care must be taken when updating the p2m table since it's important
to limit table memory consumption and reuse the existing leaf pages which get
freed when an entire leaf page is set to the identity map. To implement this,
mapping updates are grouped into blocks with table entries getting cached
temporarily and then released.

On my test system before:
Total pages: 2105014
Total contiguous: 1640635

After:
Total pages: 2105014
Total contiguous: 2098904
Signed-off-by: NMatthew Rushton <mrushton@amazon.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
      4fbb67e3
  19. 01 8月, 2014 1 次提交
  21. 15 5月, 2014 4 次提交
  23. 18 3月, 2014 1 次提交
  25. 03 2月, 2014 1 次提交
  27. 31 1月, 2014 1 次提交
    • Z
      xen/grant-table: Avoid m2p_override during mapping · 08ece5bb
      由 Zoltan Kiss 提交于 
      The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the original functions were renamed to __gnttab_[un]map_refs, with a new
  parameter m2p_override
- based on m2p_override either they follow the original behaviour, or just set
  the private flag and call set_phys_to_machine
- gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
  m2p_override false
- a new function gnttab_[un]map_refs_userspace provides the old behaviour

It also removes a stray space from page.h and change ret to 0 if
XENFEAT_auto_translated_physmap, as that is the only possible return value
there.

v2:
- move the storing of the old mfn in page->index to gnttab_map_refs
- move the function header update to a separate patch

v3:
- a new approach to retain old behaviour where it needed
- squash the patches into one

v4:
- move out the common bits from m2p* functions, and pass pfn/mfn as parameter
- clear page->private before doing anything with the page, so m2p_find_override
  won't race with this

v5:
- change return value handling in __gnttab_[un]map_refs
- remove a stray space in page.h
- add detail why ret = 0 now at some places

v6:
- don't pass pfn to m2p* functions, just get it locally
Signed-off-by: NZoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      08ece5bb
  29. 06 1月, 2014 2 次提交
    • M
      xen/pvh: Setup up shared_info. · 4dd322bc
      由 Mukesh Rathor 提交于 
      For PVHVM the shared_info structure is provided via the same way
as for normal PV guests (see include/xen/interface/xen.h).

That is during bootup we get 'xen_start_info' via the %esi register
in startup_xen. Then later we extract the 'shared_info' from said
structure (in xen_setup_shared_info) and start using it.

The 'xen_setup_shared_info' is all setup to work with auto-xlat
guests, but there are two functions which it calls that are not:
xen_setup_mfn_list_list and xen_setup_vcpu_info_placement.
This patch modifies the P2M code (xen_setup_mfn_list_list)
while the "Piggyback on PVHVM for event channels" modifies
the xen_setup_vcpu_info_placement.
Signed-off-by: NMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      4dd322bc
    • K
      xen/pvh: Don't setup P2M tree. · 696fd7c5
      由 Konrad Rzeszutek Wilk 提交于 
      P2M is not available for PVH. Fortunatly for us the
P2M code already has mostly the support for auto-xlat guest thanks to
commit 3d24bbd7
"grant-table: call set_phys_to_machine after mapping grant refs"
which: "
introduces set_phys_to_machine calls for auto_translated guests
(even on x86) in gnttab_map_refs and gnttab_unmap_refs.
translated by swiotlb-xen... " so we don't need to muck much.

with above mentioned "commit you'll get set_phys_to_machine calls
from gnttab_map_refs and gnttab_unmap_refs but PVH guests won't do
anything with them " (Stefano Stabellini) which is OK - we want
them to be NOPs.

This is because we assume that an "IOMMU is always present on the
plaform and Xen is going to make the appropriate IOMMU pagetable
changes in the hypercall implementation of GNTTABOP_map_grant_ref
and GNTTABOP_unmap_grant_ref, then eveything should be transparent
from PVH priviligied point of view and DMA transfers involving
foreign pages keep working with no issues[sp]

Otherwise we would need a P2M (and an M2P) for PVH priviligied to
track these foreign pages .. (see arch/arm/xen/p2m.c)."
(Stefano Stabellini).

We still have to inhibit the building of the P2M tree.
That had been done in the past by not calling
xen_build_dynamic_phys_to_machine (which setups the P2M tree
and gives us virtual address to access them). But we are missing
a check for xen_build_mfn_list_list - which was continuing to setup
the P2M tree and would blow up at trying to get the virtual
address of p2m_missing (which would have been setup by
xen_build_dynamic_phys_to_machine).

Hence a check is needed to not call xen_build_mfn_list_list when
running in auto-xlat mode.

Instead of replicating the check for auto-xlat in enlighten.c
do it in the p2m.c code. The reason is that the xen_build_mfn_list_list
is called also in xen_arch_post_suspend without any checks for
auto-xlat. So for PVH or PV with auto-xlat - we would needlessly
allocate space for an P2M tree.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
      696fd7c5
  31. 10 10月, 2013 1 次提交
  33. 25 9月, 2013 1 次提交
    • D
      xen/p2m: check MFN is in range before using the m2p table · 0160676b
      由 David Vrabel 提交于 
      On hosts with more than 168 GB of memory, a 32-bit guest may attempt
to grant map an MFN that is error cannot lookup in its mapping of the
m2p table.  There is an m2p lookup as part of m2p_add_override() and
m2p_remove_override().  The lookup falls off the end of the mapped
portion of the m2p and (because the mapping is at the highest virtual
address) wraps around and the lookup causes a fault on what appears to
be a user space address.

do_page_fault() (thinking it's a fault to a userspace address), tries
to lock mm->mmap_sem.  If the gntdev device is used for the grant map,
m2p_add_override() is called from from gnttab_mmap() with mm->mmap_sem
already locked.  do_page_fault() then deadlocks.

The deadlock would most commonly occur when a 64-bit guest is started
and xenconsoled attempts to grant map its console ring.

Introduce mfn_to_pfn_no_overrides() which checks the MFN is within the
mapped portion of the m2p table before accessing the table and use
this in m2p_add_override(), m2p_remove_override(), and mfn_to_pfn()
(which already had the correct range check).

All faults caused by accessing the non-existant parts of the m2p are
thus within the kernel address space and exception_fixup() is called
without trying to lock mm->mmap_sem.

This means that for MFNs that are outside the mapped range of the m2p
then mfn_to_pfn() will always look in the m2p overrides.  This is
correct because it must be a foreign MFN (and the PFN in the m2p in
this case is only relevant for the other domain).
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
--
v3: check for auto_translated_physmap in mfn_to_pfn_no_overrides()
v2: in mfn_to_pfn() look in m2p_overrides if the MFN is out of
    range as it's probably foreign.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
      0160676b
  35. 09 9月, 2013 1 次提交
  37. 20 8月, 2013 1 次提交
  39. 09 8月, 2013 1 次提交
  41. 12 9月, 2012 1 次提交
    • S
      xen/m2p: do not reuse kmap_op->dev_bus_addr · 2fc136ee
      由 Stefano Stabellini 提交于 
      If the caller passes a valid kmap_op to m2p_add_override, we use
kmap_op->dev_bus_addr to store the original mfn, but dev_bus_addr is
part of the interface with Xen and if we are batching the hypercalls it
might not have been written by the hypervisor yet. That means that later
on Xen will write to it and we'll think that the original mfn is
actually what Xen has written to it.

Rather than "stealing" struct members from kmap_op, keep using
page->index to store the original mfn and add another parameter to
m2p_remove_override to get the corresponding kmap_op instead.
It is now responsibility of the caller to keep track of which kmap_op
corresponds to a particular page in the m2p_override (gntdev, the only
user of this interface that passes a valid kmap_op, is already doing that).

CC: stable@kernel.org
Reported-and-Tested-By: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      2fc136ee
  43. 05 9月, 2012 1 次提交
    • K
      xen/p2m: Fix one-off error in checking the P2M tree directory. · 50e90041
      由 Konrad Rzeszutek Wilk 提交于 
      We would traverse the full P2M top directory (from 0->MAX_DOMAIN_PAGES
inclusive) when trying to figure out whether we can re-use some of the
P2M middle leafs.

Which meant that if the kernel was compiled with MAX_DOMAIN_PAGES=512
we would try to use the 512th entry. Fortunately for us the p2m_top_index
has a check for this:

 BUG_ON(pfn >= MAX_P2M_PFN);

which we hit and saw this:

(XEN) domain_crash_sync called from entry.S
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
(XEN) ----[ Xen-4.1.2-OVM  x86_64  debug=n  Tainted:    C ]----
(XEN) CPU:    0
(XEN) RIP:    e033:[<ffffffff819cadeb>]
(XEN) RFLAGS: 0000000000000212   EM: 1   CONTEXT: pv guest
(XEN) rax: ffffffff81db5000   rbx: ffffffff81db4000   rcx: 0000000000000000
(XEN) rdx: 0000000000480211   rsi: 0000000000000000   rdi: ffffffff81db4000
(XEN) rbp: ffffffff81793db8   rsp: ffffffff81793d38   r8:  0000000008000000
(XEN) r9:  4000000000000000   r10: 0000000000000000   r11: ffffffff81db7000
(XEN) r12: 0000000000000ff8   r13: ffffffff81df1ff8   r14: ffffffff81db6000
(XEN) r15: 0000000000000ff8   cr0: 000000008005003b   cr4: 00000000000026f0
(XEN) cr3: 0000000661795000   cr2: 0000000000000000

Fixes-Oracle-Bug: 14570662
CC: stable@vger.kernel.org # only for v3.5
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      50e90041