Steven Noonan forwarded a users report where they had a problem starting
vsftpd on a Xen paravirtualized guest, with this in dmesg:

  BUG: Bad page map in process vsftpd  pte:8000000493b88165 pmd:e9cc01067
  page:ffffea00124ee200 count:0 mapcount:-1 mapping:     (null) index:0x0
  page flags: 0x2ffc0000000014(referenced|dirty)
  addr:00007f97eea74000 vm_flags:00100071 anon_vma:ffff880e98f80380 mapping:          (null) index:7f97eea74
  CPU: 4 PID: 587 Comm: vsftpd Not tainted 3.12.7-1-ec2 #1
  Call Trace:
    dump_stack+0x45/0x56
    print_bad_pte+0x22e/0x250
    unmap_single_vma+0x583/0x890
    unmap_vmas+0x65/0x90
    exit_mmap+0xc5/0x170
    mmput+0x65/0x100
    do_exit+0x393/0x9e0
    do_group_exit+0xcc/0x140
    SyS_exit_group+0x14/0x20
    system_call_fastpath+0x1a/0x1f
  Disabling lock debugging due to kernel taint
  BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:0 val:-1
  BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:1 val:1

The issue could not be reproduced under an HVM instance with the same
kernel, so it appears to be exclusive to paravirtual Xen guests.  He
bisected the problem to commit 1667918b ("mm: numa: clear numa
hinting information on mprotect") that was also included in 3.12-stable.

The problem was related to how xen translates ptes because it was not
accounting for the _PAGE_NUMA bit.  This patch splits pte_present to add
a pteval_present helper for use by xen so both bare metal and xen use
the same code when checking if a PTE is present.

[mgorman@suse.de: wrote changelog, proposed minor modifications]
[akpm@linux-foundation.org: fix typo in comment]
Reported-by: NSteven Noonan <steven@uplinklabs.net>
Tested-by: NSteven Noonan <steven@uplinklabs.net>
Signed-off-by: NElena Ufimtseva <ufimtseva@gmail.com>
Signed-off-by: NMel Gorman <mgorman@suse.de>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org>	[3.12+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The paravirt thunks use a hack of using a static reference to a static
function to reference that function from the top level statement.

This assumes that gcc always generates static function names in a specific
format, which is not necessarily true.

Simply make these functions global and asmlinkage or __visible. This way the
static __used variables are not needed and everything works.

Functions with arguments are __visible to keep the register calling
convention on 32bit.

Changed in paravirt and in all users (Xen and vsmp)

v2: Use __visible for functions with arguments

Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ido Yariv <ido@wizery.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-5-git-send-email-andi@firstfloor.orgSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

We also optimize one - the TLB flush. The native operation would
needlessly IPI offline VCPUs causing extra wakeups. Using the
Xen one avoids that and lets the hypervisor determine which
VCPU needs the TLB flush.
Signed-off-by: NMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

.. which are surprisingly small compared to the amount for PV code.

PVH uses mostly native mmu ops, we leave the generic (native_*) for
the majority and just overwrite the baremetal with the ones we need.

At startup, we are running with pre-allocated page-tables
courtesy of the tool-stack. But we still need to graft them
in the Linux initial pagetables. However there is no need to
unpin/pin and change them to R/O or R/W.

Note that the xen_pagetable_init due to 7836fec9d0994cc9c9150c5a33f0eb0eb08a335a
"xen/mmu/p2m: Refactor the xen_pagetable_init code." does not
need any changes - we just need to make sure that xen_post_allocator_init
does not alter the pvops from the default native one.
Signed-off-by: NMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Stefano noticed that the code runs only under 64-bit so
the comments about 32-bit are pointless.

Also we change the condition for xen_revector_p2m_tree
returning the same value (because it could not allocate
a swath of space to put the new P2M in) or it had been
called once already. In such we return early from the
function.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The revectoring and copying of the P2M only happens when
!auto-xlat and on 64-bit builds. It is not obvious from
the code, so lets have seperate 32 and 64-bit functions.

We also invert the check for auto-xlat to make the code
flow simpler.
Suggested-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If split page table lock is in use, we embed the lock into struct page
of table's page.  We have to disable split lock, if spinlock_t is too
big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC
enabled.

This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.

page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to spinlock_t.

The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
pgtable_pmd_page_ctor() for PMD table.  All other helpers converted to
support dynamically allocated page->ptl.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We're going to introduce split page table lock for PMD level.  Let's
rename existing split ptlock for PTE level to avoid confusion.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: NAlex Thorlton <athorlton@sgi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.

We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.

Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.

Changes in v6:
- remove extra spaces.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Modify xen_create_contiguous_region to return the dma address of the
newly contiguous buffer.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>


Changes in v4:
- use virt_to_machine instead of virt_to_bus.

Jan Beulich spotted that the PAT MSR settings in the Xen public
document that "the first (PAT6) column was wrong across the
board, and the column for PAT7 was missing altogether."

This updates it to be in sync.

CC: Jan Beulich <jbeulich@suse.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NJan Beulich <jbeulich@suse.com>

Make a copy of the IDT (as seen via the "sidt" instruction) read-only.
This primarily removes the IDT from being a target for arbitrary memory
write attacks, and has the added benefit of also not leaking the kernel
base offset, if it has been relocated.

We already did this on vendor == Intel and family == 5 because of the
F0 0F bug -- regardless of if a particular CPU had the F0 0F bug or
not.  Since the workaround was so cheap, there simply was no reason to
be very specific.  This patch extends the readonly alias to all CPUs,
but does not activate the #PF to #UD conversion code needed to deliver
the proper exception in the F0 0F case except on Intel family 5
processors.
Signed-off-by: NKees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130410192422.GA17344@www.outflux.net
Cc: Eric Northup <digitaleric@google.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Invoking arch_flush_lazy_mmu_mode() results in calls to
preempt_enable()/disable() which may have performance impact.

Since lazy MMU is not used on bare metal we can patch away
arch_flush_lazy_mmu_mode() so that it is never called in such
environment.

[ hpa: the previous patch "Fix vmalloc_fault oops during lazy MMU
  updates" may cause a minor performance regression on
  bare metal.  This patch resolves that performance regression.  It is
  somewhat unclear to me if this is a good -stable candidate. ]
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1364045796-10720-2-git-send-email-konrad.wilk@oracle.comTested-by: NJosh Boyer <jwboyer@redhat.com>
Tested-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> SEE NOTE ABOVE

Occassionaly on a DL380 G4 the guest would crash quite early with this:

(XEN) d244:v0: unhandled page fault (ec=0003)
(XEN) Pagetable walk from ffffffff84dc7000:
(XEN)  L4[0x1ff] = 00000000c3f18067 0000000000001789
(XEN)  L3[0x1fe] = 00000000c3f14067 000000000000178d
(XEN)  L2[0x026] = 00000000dc8b2067 0000000000004def
(XEN)  L1[0x1c7] = 00100000dc8da067 0000000000004dc7
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 244 (vcpu#0) crashed on cpu#3:
(XEN) ----[ Xen-4.1.3OVM  x86_64  debug=n  Not tainted ]----
(XEN) CPU:    3
(XEN) RIP:    e033:[<ffffffff81263f22>]
(XEN) RFLAGS: 0000000000000216   EM: 1   CONTEXT: pv guest
(XEN) rax: 0000000000000000   rbx: ffffffff81785f88   rcx: 000000000000003f
(XEN) rdx: 0000000000000000   rsi: 00000000dc8da063   rdi: ffffffff84dc7000

The offending code shows it to be a loop writting the value zero
(%rax) in the %rdi (the L4 provided by Xen) register:

   0: 44 00 00             add    %r8b,(%rax)
   3: 31 c0                 xor    %eax,%eax
   5: b9 40 00 00 00       mov    $0x40,%ecx
   a: 66 0f 1f 84 00 00 00 nopw   0x0(%rax,%rax,1)
  11: 00 00
  13: ff c9                 dec    %ecx
  15:* 48 89 07             mov    %rax,(%rdi)     <-- trapping instruction
  18: 48 89 47 08           mov    %rax,0x8(%rdi)
  1c: 48 89 47 10           mov    %rax,0x10(%rdi)

which fails. xen_setup_kernel_pagetable recycles some of the Xen's
page-table entries when it has switched over to its Linux page-tables.

Right before try to clear the page, we  make a hypercall to change
it from _RO to  _RW and that works (otherwise we would hit an BUG()).
And the _RW flag is set for that page:
(XEN)  L1[0x1c7] = 001000004885f067 0000000000004dc7

The error code is 3, so PFEC_page_present and PFEC_write_access, so page is
present (correct), and we tried to write to the page, but a violation
occurred. The one theory is that the the page entries in hardware
(which are cached) are not up to date with what we just set. Especially
as we have just done an CR3 write and flushed the multicalls.

This patch does solve the problem by flusing out the TLB page
entry after changing it from _RO to _RW and we don't hit this
issue anymore.

Fixed-Oracle-Bug: 16243091 [ON OCCASIONS VM START GOES INTO
'CRASH' STATE: CLEAR_PAGE+0X12 ON HP DL380 G4]
Reported-and-Tested-by: NSaar Maoz <Saar.Maoz@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We move the setting of write_cr3 from the early bootup variant
(see git commit 0cc9129d
"x86-64, xen, mmu: Provide an early version of write_cr3.")
to a more appropiate location.

This new location sets all of the other non-early variants
of pvops calls - and most importantly is before the
alternative_asm mechanism kicks in.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

With commit 8170e6be ("x86, 64bit: Use a #PF handler to materialize
early mappings on demand") we started hitting an early bootup crash
where the Xen hypervisor would inform us that:

    (XEN) d7:v0: unhandled page fault (ec=0000)
    (XEN) Pagetable walk from ffffea000005b2d0:
    (XEN)  L4[0x1d4] = 0000000000000000 ffffffffffffffff
    (XEN) domain_crash_sync called from entry.S
    (XEN) Domain 7 (vcpu#0) crashed on cpu#3:
    (XEN) ----[ Xen-4.2.0  x86_64  debug=n  Not tainted ]----

.. that Xen was unable to context switch back to dom0.

Looking at the calling stack we find:

    [<ffffffff8103feba>] xen_get_user_pgd+0x5a  <--
    [<ffffffff8103feba>] xen_get_user_pgd+0x5a
    [<ffffffff81042d27>] xen_write_cr3+0x77
    [<ffffffff81ad2d21>] init_mem_mapping+0x1f9
    [<ffffffff81ac293f>] setup_arch+0x742
    [<ffffffff81666d71>] printk+0x48

We are trying to figure out whether we need to up-date the user PGD as
well.  Please keep in mind that under 64-bit PV guests we have a limited
amount of rings: 0 for the Hypervisor, and 1 for both the Linux kernel
and user-space.  As such the Linux pvops'fied version of write_cr3
checks if it has to update the user-space cr3 as well.

That clearly is not needed during early bootup.  The recent changes (see
above git commit) streamline the x86 page table allocation to be much
simpler (And also incidentally the #PF handler ends up in spirit being
similar to how the Xen toolstack sets up the initial page-tables).

The fix is to have an early-bootup version of cr3 that just loads the
kernel %cr3.  The later version - which also handles user-page
modifications will be used after the initial page tables have been
setup.

[ hpa: removed a redundant #ifdef and made the new function __init.
  Also note that x86-32 already has such an early xen_write_cr3. ]
Tested-by: N"H. Peter Anvin" <hpa@zytor.com>
Reported-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1361579812-23709-1-git-send-email-konrad.wilk@oracle.comSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For Xen on ARM a PFN is 64 bits so we need to use the appropriate
type here.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: include the necessary header,
     Reported-by: Fengguang Wu <fengguang.wu@intel.com> ]

Also introduce xen_unmap_domain_mfn_range. These are the parts of
Mukesh's "xen/pvh: Implement MMU changes for PVH" which are also
needed as a baseline for ARM privcmd support.

The original patch was:
Signed-off-by: NMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This derivative is also:
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>

Page table area are pre-mapped now after
	x86, mm: setup page table in top-down
	x86, mm: Remove early_memremap workaround for page table accessing on 64bit

mapping_pagetable_reserve is not used anymore, so remove it.

Also remove operation in mask_rw_pte(), as modified allow_low_page
always return pages that are already mapped, moreover
xen_alloc_pte_init, xen_alloc_pmd_init, etc, will mark the page RO
before hooking it into the pagetable automatically.

-v2: add changelog about mask_rw_pte() from Stefano.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-27-git-send-email-yinghai@kernel.org
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

As Mukesh explained it, the MMUEXT_TLB_FLUSH_ALL allows the
hypervisor to do a TLB flush on all active vCPUs. If instead
we were using the generic one (which ends up being xen_flush_tlb)
we end up making the MMUEXT_TLB_FLUSH_LOCAL hypercall. But
before we make that hypercall the kernel will IPI all of the
vCPUs (even those that were asleep from the hypervisor
perspective). The end result is that we needlessly wake them
up and do a TLB flush when we can just let the hypervisor
do it correctly.

This patch gives around 50% speed improvement when migrating
idle guest's from one host to another.

Oracle-bug: 14630170

CC: stable@vger.kernel.org
Tested-by: NJingjie Jiang <jingjie.jiang@oracle.com>
Suggested-by: NMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Register pfn_is_ram helper speed up reading /proc/vmcore in the kdump
kernel. See commit message of 997c136f ("fs/proc/vmcore.c: add hook
to read_from_oldmem() to check for non-ram pages") for details.

It makes use of a new hvmop HVMOP_get_mem_type which was introduced in
xen 4.2 (23298:26413986e6e0) and backported to 4.1.1.

The new function is currently only enabled for reading /proc/vmcore.
Later it will be used also for the kexec kernel. Since that requires
more changes in the generic kernel make it static for the time being.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

At this stage x86_init.paging.pagetable_setup_done is only used in the
XEN case. Move its content in the x86_init.paging.pagetable_init setup
function and remove the now unused x86_init.paging.pagetable_setup_done
remaining infrastructure.
Signed-off-by: NAttilio Rao <attilio.rao@citrix.com>
Acked-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-5-git-send-email-attilio.rao@citrix.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Move the paging_init() call to the platform specific pagetable_init()
function, so we can get rid of the extra pagetable_setup_done()
function pointer.
Signed-off-by: NAttilio Rao <attilio.rao@citrix.com>
Acked-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-4-git-send-email-attilio.rao@citrix.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

In preparation for unifying the pagetable_setup_start() and
pagetable_setup_done() setup functions, rename appropriately all the
infrastructure related to pagetable_setup_start().
Signed-off-by: NAttilio Rao <attilio.rao@citrix.com>
Ackedd-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-3-git-send-email-attilio.rao@citrix.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

We either use swapper_pg_dir or the argument is unused. Preparatory
patch to simplify platform pagetable setup further.
Signed-off-by: NAttilio Rao <attilio.rao@citrix.com>
Ackedb-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-2-git-send-email-attilio.rao@citrix.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Callers of xen_remap_domain_range() need to know if the remap failed
because frame is currently paged out.  So they can retry the remap
later on.  Return -ENOENT in this case.

This assumes that the error codes returned by Xen are a subset of
those used by the kernel.  It is unclear if this is defined as part of
the hypercall ABI.
Acked-by: NAndres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

While TLB_FLUSH_ALL gets passed as 'end' argument to
flush_tlb_others(), the Xen code was made to check its 'start'
parameter. That may give a incorrect op.cmd to MMUEXT_INVLPG_MULTI
instead of MMUEXT_TLB_FLUSH_MULTI. Then it causes some page can not
be flushed from TLB.

This patch fixed this issue.
Reported-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Acked-by: NJan Beulich <jbeulich@suse.com>
Tested-by: NYongjie Ren <yongjie.ren@intel.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If the P2M revectoring would fail, we would try to continue on by
cleaning the PMD for L1 (PTE) page-tables. The xen_cleanhighmap
is greedy and erases the PMD on both boundaries. Since the P2M
array can share the PMD, we would wipe out part of the __ka
that is still used in the P2M tree to point to P2M leafs.

This fixes it by bypassing the revectoring and continuing on.
If the revector fails, a nice WARN is printed so we can still
troubleshoot this.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We call memblock_reserve for [start of mfn list] -> [PMD aligned end
of mfn list] instead of <start of mfn list> -> <page aligned end of mfn list].

This has the disastrous effect that if at bootup the end of mfn_list is
not PMD aligned we end up returning to memblock parts of the region
past the mfn_list array. And those parts are the PTE tables with
the disastrous effect of seeing this at bootup:

Write protecting the kernel read-only data: 10240k
Freeing unused kernel memory: 1860k freed
Freeing unused kernel memory: 200k freed
(XEN) mm.c:2429:d0 Bad type (saw 1400000000000002 != exp 7000000000000000) for mfn 116a80 (pfn 14e26)
...
(XEN) mm.c:908:d0 Error getting mfn 116a83 (pfn 14e2a) from L1 entry 8000000116a83067 for l1e_owner=0, pg_owner=0
(XEN) mm.c:908:d0 Error getting mfn 4040 (pfn 5555555555555555) from L1 entry 0000000004040601 for l1e_owner=0, pg_owner=0
.. and so on.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Please first read the description in "xen/mmu: Copy and revector the
P2M tree."

At this stage, the __ka address space (which is what the old
P2M tree was using) is partially disassembled. The cleanup_highmap
has removed the PMD entries from 0-16MB and anything past _brk_end
up to the max_pfn_mapped (which is the end of the ramdisk).

The xen_remove_p2m_tree and code around has ripped out the __ka for
the old P2M array.

Here we continue on doing it to where the Xen page-tables were.
It is safe to do it, as the page-tables are addressed using __va.
For good measure we delete anything that is within MODULES_VADDR
and up to the end of the PMD.

At this point the __ka only contains PMD entries for the start
of the kernel up to __brk.

[v1: Per Stefano's suggestion wrapped the MODULES_VADDR in debug]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Please first read the description in "xen/p2m: Add logic to revector a
P2M tree to use __va leafs" patch.

The 'xen_revector_p2m_tree()' function allocates a new P2M tree
copies the contents of the old one in it, and returns the new one.

At this stage, the __ka address space (which is what the old
P2M tree was using) is partially disassembled. The cleanup_highmap
has removed the PMD entries from 0-16MB and anything past _brk_end
up to the max_pfn_mapped (which is the end of the ramdisk).

We have revectored the P2M tree (and the one for save/restore as well)
to use new shiny __va address to new MFNs. The xen_start_info
has been taken care of already in 'xen_setup_kernel_pagetable()' and
xen_start_info->shared_info in 'xen_setup_shared_info()', so
we are free to roam and delete PMD entries - which is exactly what
we are going to do. We rip out the __ka for the old P2M array.

[v1: Fix smatch warnings]
[v2: memset was doing 0 instead of 0xff]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

As we are not using them. We end up only using the L1 pagetables
and grafting those to our page-tables.

[v1: Per Stefano's suggestion squashed two commits]
[v2: Per Stefano's suggestion simplified loop]
[v3: Fix smatch warnings]
[v4: Add more comments]
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

B/c we do not need it. During the startup the Xen provides
us with all the initial memory mapped that we need to function.

The initial memory mapped is up to the bootstack, which means
we can reference using __ka up to 4.f):

(from xen/interface/xen.h):

 4. This the order of bootstrap elements in the initial virtual region:
   a. relocated kernel image
   b. initial ram disk              [mod_start, mod_len]
   c. list of allocated page frames [mfn_list, nr_pages]
   d. start_info_t structure        [register ESI (x86)]
   e. bootstrap page tables         [pt_base, CR3 (x86)]
   f. bootstrap stack               [register ESP (x86)]

(initial ram disk may be ommitted).

[v1: More comments in git commit]
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

After all, this is what it is there for.
Acked-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Which is that the level2_kernel_pgt (__ka virtual addresses)
and level2_ident_pgt (__va virtual address) contain the same
PMD entries. So if you modify a PTE in __ka, it will be reflected
in __va (and vice-versa).
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We don't need to return the new PGD - as we do not use it.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This patch removes the "return -ENOSYS" for auto_translated_physmap
guests from privcmd_mmap, thus it allows ARM guests to issue privcmd
mmap calls. However privcmd mmap calls are still going to fail for HVM
and hybrid guests on x86 because the xen_remap_domain_mfn_range
implementation is currently PV only.

Changes in v2:

- better commit message;
- return -EINVAL from xen_remap_domain_mfn_range if
  auto_translated_physmap.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When constructing the initial page tables, if the MFN for a usable PFN
is missing in the p2m then that frame is initially ballooned out.  In
this case, zero the PTE (as in decrease_reservation() in
drivers/xen/balloon.c).

This is obviously safe instead of having an valid PTE with an MFN of
INVALID_P2M_ENTRY (~0).
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In xen_set_pte() if batching is unavailable (because the caller is in
an interrupt context such as handling a page fault) it would fall back
to using native_set_pte() and trapping and emulating the PTE write.

On 32-bit guests this requires two traps for each PTE write (one for
each dword of the PTE).  Instead, do one mmu_update hypercall
directly.

During construction of the initial page tables, continue to use
native_set_pte() because most of the PTEs being set are in writable
and unpinned pages (see phys_pmd_init() in arch/x86/mm/init_64.c) and
using a hypercall for this is very expensive.

This significantly improves page fault performance in 32-bit PV
guests.

lmbench3 test  Before    After     Improvement
----------------------------------------------
lat_pagefault  3.18 us   2.32 us   27%
lat_proc fork  356 us    313.3 us  11%
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>