Vito said:

: The system has many usb disks coming and going day to day, with their
: respective bdi's having min_ratio set to 1 when inserted.  It works for
: some time until eventually min_ratio can no longer be set, even when the
: active set of bdi's seen in /sys/class/bdi/*/min_ratio doesn't add up to
: anywhere near 100.
:
: This then leads to an unrelated starvation problem caused by write-heavy
: fuse mounts being used atop the usb disks, a problem the min_ratio setting
: at the underlying devices bdi effectively prevents.

Fix this leakage by resetting the bdi min_ratio when unregistering the
BDI.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Reported-by: NVito Caputo <lkml@pengaru.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If dmi_get_system_info() returns NULL, pch_phub_probe() will dereferencea
a zero pointer.

This oops was observed on an Atom based board which has no BIOS, but a
bootloder which doesn't privde DMI data.
Signed-off-by: NAlexander Stein <alexander.stein@systec-electronic.com>
Cc: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following build error:

  arch/xtensa/include/asm/uaccess.h:403: error: implicit declaration of function 'prefetch'
  arch/xtensa/include/asm/uaccess.h:412: error: implicit declaration of function 'prefetchw'
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prevent an arbitrary kernel read.  Check the user pointer with access_ok()
before copying data in.

[akpm@linux-foundation.org: s/EIO/EFAULT/]
Signed-off-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: Christian Zankel <chris@zankel.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In a subsquent patch I have a const struct page in my hand...

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These uses are read-only and in a subsequent patch I have a const struct
page in my hand...

[akpm@linux-foundation.org: fix warnings in lowmem_page_address()]
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is needed on HIGHMEM systems - we don't always have a virtual
address so store the physical address and map it in as needed.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This:

    vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT)

is incorrect on 32-bit.  It causes us to & the pgoff with something that
looks like this (for a 4m hugepage): 0xfff003ff.  The mask should be
flipped and *then* shifted, to give you 0x0000_03fff.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a semaphore array is removed and in parallel a sleeping task is woken
up (signal or timeout, does not matter), then the woken up task does not
wait until wake_up_sem_queue_do() is completed.  This will cause crashes,
because wake_up_sem_queue_do() will read from a stale pointer.

The fix is simple: Regardless of anything, always call get_queue_result().
This function waits until wake_up_sem_queue_do() has finished it's task.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=27142Reported-by: NYuriy Yevtukhov <yuriy@ucoz.com>
Reported-by: NHarald Laabs <kernel@dasr.de>
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: <stable@kernel.org>		[2.6.35+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] s5pv210: make needlessly global symbols static
  [CPUFREQ] exynos4210: make needlessly global symbols static
  [CPUFREQ] S3C6410: Add some lower frequencies for 800MHz base clock operation
  [CPUFREQ] S5PV210: Add reboot notifier to prevent system hang
  [CPUFREQ] S5PV210: Adjust udelay prior to voltage scaling down
  [CPUFREQ] S5PV210: Lock a mutex while changing the cpu frequency
  [CPUFREQ] S5PV210: Add pm_notifier to prevent system unstable
  [CPUFREQ] S5PV210: Add arm/int voltage control support
  [CPUFREQ] S5PV210: Add additional symantics for "relation" in cpufreq with pm
  [CPUFREQ] S3C64xx: Notify transition complete as soon as frequency changed
  [CPUFREQ] S3C6410: Support 800MHz operation in cpufreq
  [CPUFREQ] s5pv210-cpufreq.c: Add missing clk_put
  [CPUFREQ] Move compile for S3C64XX cpufreq to /drivers/cpufreq
  [CPUFREQ] Remove some vi noise that escaped into the Makefile.
  [CPUFREQ] Move ARM Samsung cpufreq drivers to drivers/cpufreq/
  [CPUFREQ/S3C64xx] Move S3C64xx CPUfreq driver into drivers/cpufreq
  [CPUFREQ] Handle CPUs with different capabilities in acpi-cpufreq

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (145 commits)
  bnx2x: use pci_pcie_cap()
  bnx2x: fix bnx2x_stop_on_error flow in bnx2x_sp_rtnl_task
  bnx2x: enable internal target-read for 57712 and up only
  bnx2x: count statistic ramrods on EQ to prevent MC assert
  bnx2x: fix loopback for non 10G link
  bnx2x: dcb - send all unmapped priorities to same COS as L2
  iwlwifi: Fix build with CONFIG_PM disabled.
  gre: fix improper error handling
  ipv4: use RT_TOS after some rt_tos conversions
  via-velocity: remove duplicated #include
  qlge: remove duplicated #include
  igb: remove duplicated #include
  can: c_can: remove duplicated #include
  bnad: remove duplicated #include
  net: allow netif_carrier to be called safely from IRQ
  bna: Header File Consolidation
  bna: HW Error Counter Fix
  bna: Add HW Semaphore Unlock Logic
  bna: IOC Event Name Change
  bna: Mboxq Flush When IOC Disabled
  ...

So use mdelay(20) instead.  Fixes this build error:

  ERROR: "__bad_udelay" [drivers/staging/gma500/psb_gfx.ko] undefined!
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  ata: PATA_ARASAN_CF depends on DMADEVICES
  ata: remove unnecessary code
  [libata] Prevent warning during PMP error recovery
  ahci: RAID-mode SATA patch for Intel Panther Point DeviceIDs
  pata_it821x: Fix RAID type display, by adding missing comma
  sata_dwc_460ex: fix error path
  ahci: Enable SB600 64bit DMA on Asus M3A
  libata: report link resume failure as KERN_WARNING instead of ERR
  ahci: move ahci_sb600_softreset to libahci.c and rename it
  libata: leave port thawed after reset failure
  ata: sata_via: Use dev_dbg
  ata: Add and use ata_print_version_once
  ata: Convert ata_<foo>_printk(KERN_<LEVEL> to ata_<foo>_<level>
  ata: Convert dev_printk(KERN_<LEVEL> to dev_<level>(

Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NVladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NVladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NShmulik Ravid <shmulikr@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch includes:
 - Counting statistics ramrods as EQ ramrods the way they should be. This
   accounting is meant to prevent MC asserts in case of software bugs.
 - Fixes in debug facilities which were added while working on one of such
   bugs.
Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NVladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Also fixes minor formatting in that function.
Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NYaniv Rosner <yanivr@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As a result of DCBX negotiation some priorities maybe untouched and still
unmapped to any COS; instead of sending them to COS0 we assign them
to the same COS as L2 traffic - to avoid collisions with storage class of
service.
Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (237 commits)
  ARM: 7004/1: fix traps.h compile warnings
  ARM: 6998/2: kernel: use proper memory barriers for bitops
  ARM: 6997/1: ep93xx: increase NR_BANKS to 16 for support of 128MB RAM
  ARM: Fix build errors caused by adding generic macros
  ARM: CPU hotplug: ensure we migrate all IRQs off a downed CPU
  ARM: CPU hotplug: pass in proper affinity mask on IRQ migration
  ARM: GIC: avoid routing interrupts to offline CPUs
  ARM: CPU hotplug: fix abuse of irqdesc->node
  ARM: 6981/2: mmci: adjust calculation of f_min
  ARM: 7000/1: LPAE: Use long long printk format for displaying the pud
  ARM: 6999/1: head, zImage: Always Enter the kernel in ARM state
  ARM: btc: avoid invalidating the branch target cache on kernel TLB maintanence
  ARM: ARM_DMA_ZONE_SIZE is no more
  ARM: mach-shark: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-sa1100: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-realview: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-pxa: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-ixp4xx: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-h720x: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-davinci: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ...

Current documentation referred to the old method of handling augmented
trees.  Update documentation to correspond with the changes done in
commit b945d6b2 ("rbtree: Undo augmented trees performance damage
and regression").

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

<linux/kernel.h> is needed for min_t. The old version
happened to work on x86 because <asm/unaligned.h>
indirectly includes <linux/kernel.h>, but it didn't
work on ARM.

<linux/kernel.h> includes <asm/byteorder.h> so it's
not necessary to include it explicitly anymore.
Signed-off-by: NLasse Collin <lasse.collin@tukaani.org>
Cc: stable <stable@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (21 commits)
  [S390] use siginfo for sigtrap signals
  [S390] dasd: add enhanced DASD statistics interface
  [S390] kvm: make sigp emerg smp capable
  [S390] disable cpu measurement alerts on a dying cpu
  [S390] initial cr0 bits
  [S390] iucv cr0 enablement bit
  [S390] race safe external interrupt registration
  [S390] remove tape block docu
  [S390] ap: toleration support for ap device type 10
  [S390] cleanup program check handler prototypes
  [S390] remove kvm mmu reload on s390
  [S390] Use gmap translation for accessing guest memory
  [S390] use gmap address spaces for kvm guest images
  [S390] kvm guest address space mapping
  [S390] fix s390 assembler code alignments
  [S390] move sie code to entry.S
  [S390] kvm: handle tprot intercepts
  [S390] qdio: clear shared DSCI before scheduling the queue handler
  [S390] reference bit testing for unmapped pages
  [S390] irqs: Do not trace arch_local_{*,irq_*} functions
  ...

* 'for-upstream' of git://openrisc.net/jonas/linux: (24 commits)
  OpenRISC: Add MAINTAINERS entry
  OpenRISC: Miscellaneous
  OpenRISC: Library routines
  OpenRISC: Headers
  OpenRISC: Traps
  OpenRISC: Module support
  OpenRISC: GPIO
  OpenRISC: Scheduling/Process management
  OpenRISC: Idle/Power management
  OpenRISC: System calls
  OpenRISC: IRQ
  OpenRISC: Timekeeping
  OpenRISC: DMA
  OpenRISC: PTrace
  OpenRISC: Build infrastructure
  OpenRISC: Signal handling
  OpenRISC: Memory management
  OpenRISC: Device tree
  OpenRISC: Boot code
  iomap: make IOPORT/PCI mapping functions conditional
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  modpost: Fix modpost's license checking V3
  module: add /sys/module/<name>/uevent files
  module: change attr callbacks to take struct module_kobject
  modules: make arch's use default loader hooks
  modules: add default loader hook implementations
  param: fix return value handling in param_set_*

* 'kvm-updates/3.1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (143 commits)
  KVM: IOMMU: Disable device assignment without interrupt remapping
  KVM: MMU: trace mmio page fault
  KVM: MMU: mmio page fault support
  KVM: MMU: reorganize struct kvm_shadow_walk_iterator
  KVM: MMU: lockless walking shadow page table
  KVM: MMU: do not need atomicly to set/clear spte
  KVM: MMU: introduce the rules to modify shadow page table
  KVM: MMU: abstract some functions to handle fault pfn
  KVM: MMU: filter out the mmio pfn from the fault pfn
  KVM: MMU: remove bypass_guest_pf
  KVM: MMU: split kvm_mmu_free_page
  KVM: MMU: count used shadow pages on prepareing path
  KVM: MMU: rename 'pt_write' to 'emulate'
  KVM: MMU: cleanup for FNAME(fetch)
  KVM: MMU: optimize to handle dirty bit
  KVM: MMU: cache mmio info on page fault path
  KVM: x86: introduce vcpu_mmio_gva_to_gpa to cleanup the code
  KVM: MMU: do not update slot bitmap if spte is nonpresent
  KVM: MMU: fix walking shadow page table
  KVM guest: KVM Steal time registration
  ...

* 'upstream/xen-tracing2' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
  xen/trace: use class for multicall trace
  xen/trace: convert mmu events to use DECLARE_EVENT_CLASS()/DEFINE_EVENT()
  xen/multicall: move *idx fields to start of mc_buffer
  xen/multicall: special-case singleton hypercalls
  xen/multicalls: add unlikely around slowpath in __xen_mc_entry()
  xen/multicalls: disable MC_DEBUG
  xen/mmu: tune pgtable alloc/release
  xen/mmu: use extend_args for more mmuext updates
  xen/trace: add tlb flush tracepoints
  xen/trace: add segment desc tracing
  xen/trace: add xen_pgd_(un)pin tracepoints
  xen/trace: add ptpage alloc/release tracepoints
  xen/trace: add mmu tracepoints
  xen/trace: add multicall tracing
  xen/trace: set up tracepoint skeleton
  xen/multicalls: remove debugfs stats
  trace/xen: add skeleton for Xen trace events

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (34 commits)
  crypto: caam - ablkcipher support
  crypto: caam - faster aead implementation
  crypto: caam - structure renaming
  crypto: caam - shorter names
  crypto: talitos - don't bad_key in ablkcipher setkey
  crypto: talitos - remove unused giv from ablkcipher methods
  crypto: talitos - don't set done notification in hot path
  crypto: talitos - ensure request ordering within a single tfm
  crypto: gf128mul - fix call to memset()
  crypto: s390 - support hardware accelerated SHA-224
  crypto: algif_hash - Handle initial af_alg_make_sg error correctly
  crypto: sha1_generic - use SHA1_BLOCK_SIZE
  hwrng: ppc4xx - add support for ppc4xx TRNG
  crypto: crypto4xx - Perform read/modify/write on device control register
  crypto: caam - fix build warning when DEBUG_FS not configured
  crypto: arc4 - Fixed coding style issues
  crypto: crc32c - Fixed coding style issue
  crypto: omap-sham - do not schedule tasklet if there is no active requests
  crypto: omap-sham - clear device flags when finishing request
  crypto: omap-sham - irq handler must not clear error code
  ...

The commit f02e8a65 sorts symbols placing each of them in its own elf section.
The sorting and merging into the canonical sections are done by the linker.
Unfortunately modpost to generate Module.symvers file parses vmlinux
(already linked) and all modules object files (which aren't linked yet).
These aren't sanitized by the linker yet. That breaks modpost that can't
detect license properly for modules. This patch makes modpost aware of
the new exported symbols structure.

Thanks to Arnaud Lacombe <lacombar@gmail.com> and Anders Kaseorg
<andersk@ksplice.com> for providing useful suggestions about code.

This work was supported by a hardware donation from the CE Linux Forum.
Reported-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAlessio Igor Bogani <abogani@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Userspace wants to manage module parameters with udev rules.
This currently only works for loaded modules, but not for
built-in ones.

To allow access to the built-in modules we need to
re-trigger all module load events that happened before any
userspace was running. We already do the same thing for all
devices, subsystems(buses) and drivers.

This adds the currently missing /sys/module/<name>/uevent files
to all module entries.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (split & trivial fix)

This simplifies the next patch, where we have an attribute on a
builtin module (ie. module == NULL).
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (split into 2)

This patch removes all the module loader hook implementations in the
architecture specific code where the functionality is the same as that
now provided by the recently added default hooks.
Signed-off-by: NJonas Bonn <jonas@southpole.se>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: NMichal Simek <monstr@monstr.eu>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The module loader code allows architectures to hook into the code by
providing a small number of entry points that each arch must implement.
This patch provides __weakly linked generic implementations of these
entry points for architectures that don't need to do anything special.
Signed-off-by: NJonas Bonn <jonas@southpole.se>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

In STANDARD_PARAM_DEF, param_set_* handles the case in which strtolfn
returns -EINVAL but it may return -ERANGE. If it returns -ERANGE,
param_set_* may set uninitialized value to the paramerter. We should handle
both cases.

The one of the cases in which strtolfn() returns -ERANGE is following:

 *Type of module parameter is long
 *Set the parameter more than LONG_MAX
Signed-off-by: NSatoru Moriya <satoru.moriya@hds.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

IOMMU interrupt remapping support provides a further layer of
isolation for device assignment by preventing arbitrary interrupt
block DMA writes by a malicious guest from reaching the host.  By
default, we should require that the platform provides interrupt
remapping support, with an opt-in mechanism for existing behavior.

Both AMD IOMMU and Intel VT-d2 hardware support interrupt
remapping, however we currently only have software support on
the Intel side.  Users wishing to re-enable device assignment
when interrupt remapping is not supported on the platform can
use the "allow_unsafe_assigned_interrupts=1" module option.

[avi: break long lines]
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Add tracepoints to trace mmio page fault
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The idea is from Avi:

| We could cache the result of a miss in an spte by using a reserved bit, and
| checking the page fault error code (or seeing if we get an ept violation or
| ept misconfiguration), so if we get repeated mmio on a page, we don't need to
| search the slot list/tree.
| (https://lkml.org/lkml/2011/2/22/221)

When the page fault is caused by mmio, we cache the info in the shadow page
table, and also set the reserved bits in the shadow page table, so if the mmio
is caused again, we can quickly identify it and emulate it directly

Searching mmio gfn in memslots is heavy since we need to walk all memeslots, it
can be reduced by this feature, and also avoid walking guest page table for
soft mmu.

[jan: fix operator precedence issue]
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Reorganize it for good using the cache
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Use rcu to protect shadow pages table to be freed, so we can safely walk it,
it should run fastly and is needed by mmio page fault
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>