A VMX preemption timer value of '0' at the time of VMEnter is
architecturally guaranteed to cause a VMExit prior to the CPU
executing any instructions in the guest.  This architectural
definition is in place to ensure that a previously expired timer
is correctly recognized by the CPU as it is possible for the timer
to reach zero and not trigger a VMexit due to a higher priority
VMExit being signalled instead, e.g. a pending #DB that morphs into
a VMExit.

Whether by design or coincidence, commit f4124500 ("KVM: nVMX:
Fully emulate preemption timer") special cased timer values of '0'
and '1' to ensure prompt delivery of the VMExit.  Unlike '0', a
timer value of '1' has no has no architectural guarantees regarding
when it is delivered.

Modify the timer emulation to trigger immediate VMExit if and only
if the timer value is '0', and document precisely why '0' is special.
Do this even if calibration of the virtual TSC failed, i.e. VMExit
will occur immediately regardless of the frequency of the timer.
Making only '0' a special case gives KVM leeway to be more aggressive
in ensuring the VMExit is injected prior to executing instructions in
the nested guest, and also eliminates any ambiguity as to why '1' is
a special case, e.g. why wasn't the threshold for a "short timeout"
set to 10, 100, 1000, etc...
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Switch to bitmap_zalloc() to show clearly what we are allocating.
Besides that it returns pointer of bitmap type instead of opaque void *.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm_commit_zap_page() has been renamed to kvm_mmu_commit_zap_page()
This patch is to fix the commit.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

I run into the following error

testing/selftests/kvm/dirty_log_test.c:285: undefined reference to `pthread_create'
testing/selftests/kvm/dirty_log_test.c:297: undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status

my gcc version is gcc version 4.8.4
"-pthread" would work everywhere
Signed-off-by: Lei Yang <Lei.Yang@windriver.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Here is the code path which shows kvm_mmu_setup() is invoked after
kvm_mmu_create(). Since kvm_mmu_setup() is only invoked in this code path,
this means the root_hpa and prev_roots are guaranteed to be invalid. And
it is not necessary to reset it again.

    kvm_vm_ioctl_create_vcpu()
        kvm_arch_vcpu_create()
            vmx_create_vcpu()
                kvm_vcpu_init()
                    kvm_arch_vcpu_init()
                        kvm_mmu_create()
        kvm_arch_vcpu_setup()
            kvm_mmu_setup()
                kvm_init_mmu()

This patch set reset_roots to false in kmv_mmu_setup().

Fixes: 50c28f21Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm should not attempt to read guest PDPTEs when CR0.PG = 0 and
CR4.PAE = 1.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When VMX is used with flexpriority disabled (because of no support or
if disabled with module parameter) MMIO interface to lAPIC is still
available in x2APIC mode while it shouldn't be (kvm-unit-tests):

PASS: apic_disable: Local apic enabled in x2APIC mode
PASS: apic_disable: CPUID.1H:EDX.APIC[bit 9] is set
FAIL: apic_disable: *0xfee00030: 50014

The issue appears because we basically do nothing while switching to
x2APIC mode when APIC access page is not used. apic_mmio_{read,write}
only check if lAPIC is disabled before proceeding to actual write.

When APIC access is virtualized we correctly manipulate with VMX controls
in vmx_set_virtual_apic_mode() and we don't get vmexits from memory writes
in x2APIC mode so there's no issue.

Disabling MMIO interface seems to be easy. The question is: what do we
do with these reads and writes? If we add apic_x2apic_mode() check to
apic_mmio_in_range() and return -EOPNOTSUPP these reads and writes will
go to userspace. When lAPIC is in kernel, Qemu uses this interface to
inject MSIs only (see kvm_apic_mem_write() in hw/i386/kvm/apic.c). This
somehow works with disabled lAPIC but when we're in xAPIC mode we will
get a real injected MSI from every write to lAPIC. Not good.

The simplest solution seems to be to just ignore writes to the region
and return ~0 for all reads when we're in x2APIC mode. This is what this
patch does. However, this approach is inconsistent with what currently
happens when flexpriority is enabled: we allocate APIC access page and
create KVM memory region so in x2APIC modes all reads and writes go to
this pre-allocated page which is, btw, the same for all vCPUs.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvm-ppc-fixes-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

Second set of PPC KVM fixes for 4.19

Two fixes for KVM on POWER machines.  Both of these relate to memory
corruption and host crashes seen when transparent huge pages are
enabled.  The first fixes a host crash that can occur when a DMA
mapping is removed by the guest and the page mapped was part of a
transparent huge page; the second fixes corruption that could occur
when a hypervisor page fault for a radix guest is being serviced at
the same time that the backing page is being collapsed or split.

Merge tag 'kvm-s390-master-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Fixes for 4.19

- more fallout from the hugetlbfs enablement
- bugfix for vma handling

The Code of Conflict is not achieving its implicit goal of fostering
civility and the spirit of 'be excellent to each other'.  Explicit
guidelines have demonstrated success in other projects and other areas
of the kernel.

Here is a Code of Conduct statement for the wider kernel.  It is based
on the Contributor Covenant as described at www.contributor-covenant.org

From this point forward, we should abide by these rules in order to help
make the kernel community a welcoming environment to participate in.
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Olof Johansson <olof@lxom.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 fixes from Ingol Molnar:
 "Misc fixes:

   - EFI crash fix

   - Xen PV fixes

   - do not allow PTI on 2-level 32-bit kernels for now

   - documentation fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/APM: Fix build warning when PROC_FS is not enabled
  Revert "x86/mm/legacy: Populate the user page-table with user pgd's"
  x86/efi: Load fixmap GDT in efi_call_phys_epilog() before setting %cr3
  x86/xen: Disable CPU0 hotplug for Xen PV
  x86/EISA: Don't probe EISA bus for Xen PV guests
  x86/doc: Fix Documentation/x86/earlyprintk.txt

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: various scheduler metrics corner case fixes, a
  sched_features deadlock fix, and a topology fix for certain NUMA
  systems"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix kernel-doc notation warning
  sched/fair: Fix load_balance redo for !imbalance
  sched/fair: Fix scale_rt_capacity() for SMT
  sched/fair: Fix vruntime_normalized() for remote non-migration wakeup
  sched/pelt: Fix update_blocked_averages() for RT and DL classes
  sched/topology: Set correct NUMA topology type
  sched/debug: Fix potential deadlock when writing to sched_features

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, but also breakpoint and x86 PMU driver fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  perf tools: Fix maps__find_symbol_by_name()
  tools headers uapi: Update tools's copy of linux/if_link.h
  tools headers uapi: Update tools's copy of linux/vhost.h
  tools headers uapi: Update tools's copies of kvm headers
  tools headers uapi: Update tools's copy of drm/drm.h
  tools headers uapi: Update tools's copy of asm-generic/unistd.h
  tools headers uapi: Update tools's copy of linux/perf_event.h
  perf/core: Force USER_DS when recording user stack data
  perf/UAPI: Clearly mark __PERF_SAMPLE_CALLCHAIN_EARLY as internal use
  perf/x86/intel: Add support/quirk for the MISPREDICT bit on Knights Landing CPUs
  perf annotate: Fix parsing aarch64 branch instructions after objdump update
  perf probe powerpc: Ignore SyS symbols irrespective of endianness
  perf event-parse: Use fixed size string for comms
  perf util: Fix bad memory access in trace info.
  perf tools: Streamline bpf examples and headers installation
  perf evsel: Fix potential null pointer dereference in perf_evsel__new_idx()
  perf arm64: Fix include path for asm-generic/unistd.h
  perf/hw_breakpoint: Simplify breakpoint enable in perf_event_modify_breakpoint
  perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint
  perf/hw_breakpoint: Remove superfluous bp->attr.disabled = 0
  ...

Pull locking fixes from Ingo Molnar:
 "Misc fixes: liblockdep fixes and ww_mutex fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/ww_mutex: Fix spelling mistake "cylic" -> "cyclic"
  locking/lockdep: Delete unnecessary #include
  tools/lib/lockdep: Add dummy task_struct state member
  tools/lib/lockdep: Add empty nmi.h
  tools/lib/lockdep: Update Sasha Levin email to MSFT
  jump_label: Fix typo in warning message
  locking/mutex: Fix mutex debug call and ww_mutex documentation

Fix build warning in apm_32.c when CONFIG_PROC_FS is not enabled:

../arch/x86/kernel/apm_32.c:1643:12: warning: 'proc_apm_show' defined but not used [-Wunused-function]
 static int proc_apm_show(struct seq_file *m, void *v)

Fixes: 3f3942ac ("proc: introduce proc_create_single{,_data}")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jiri Kosina <jikos@kernel.org>
Link: https://lkml.kernel.org/r/be39ac12-44c2-4715-247f-4dcc3c525b8b@infradead.org

Pull cifs fixes from Steve French:
 "Fixes for four CIFS/SMB3 potential pointer overflow issues, one minor
  build fix, and a build warning cleanup"

* tag '4.19-rc3-smb3-cifs' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: read overflow in is_valid_oplock_break()
  cifs: integer overflow in in SMB2_ioctl()
  CIFS: fix wrapping bugs in num_entries()
  cifs: prevent integer overflow in nxt_dir_entry()
  fs/cifs: require sha512
  fs/cifs: suppress a string overflow warning

Pull NFS client bugfixes from Anna Schumaker:
 "These are a handful of fixes for problems that Trond found. Patch #1
  and #3 have the same name, a second issue was found after applying the
  first patch.

  Stable bugfixes:
   - v4.17+: Fix tracepoint Oops in initiate_file_draining()
   - v4.11+: Fix an infinite loop on I/O

  Other fixes:
   - Return errors if a waiting layoutget is killed
   - Don't open code clearing of delegation state"

* tag 'nfs-for-4.19-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS: Don't open code clearing of delegation state
  NFSv4.1 fix infinite loop on I/O.
  NFSv4: Fix a tracepoint Oops in initiate_file_draining()
  pNFS: Ensure we return the error if someone kills a waiting layoutget
  NFSv4: Fix a tracepoint Oops in initiate_file_draining()

Pull tracing fix from Steven Rostedt:
 "This fixes an issue with the build system caused by a change that
  modifies CC_FLAGS_FTRACE. The issue is that it breaks the dependencies
  and causes "make targz-pkg" to rebuild the entire world"

* tag 'trace-v4.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/Makefile: Fix handling redefinition of CC_FLAGS_FTRACE

Pull DeviceTree fix from Rob Herring:
 "One regression for a 20 year old PowerMac:

   - Fix a regression on systems having a DT without any phandles which
     happens on a PowerMac G3"

* tag 'devicetree-fixes-for-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of: fix phandle cache creation for DTs with no phandles

Pull xen fixes from Juergen Gross:
 "This contains some minor cleanups and fixes:

   - a new knob for controlling scrubbing of pages returned by the Xen
     balloon driver to the Xen hypervisor to address a boot performance
     issue seen in large guests booted pre-ballooned

   - a fix of a regression in the gntdev driver which made it impossible
     to use fully virtualized guests (HVM guests) with a 4.19 based dom0

   - a fix in Xen cpu hotplug functionality which could be triggered by
     wrong admin commands (setting number of active vcpus to 0)

  One further note: the patches have all been under test for several
  days in another branch. This branch has been rebased in order to avoid
  merge conflicts"

* tag 'for-linus-4.19c-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/gntdev: fix up blockable calls to mn_invl_range_start
  xen: fix GCC warning and remove duplicate EVTCHN_ROW/EVTCHN_COL usage
  xen: avoid crash in disable_hotplug_cpu
  xen/balloon: add runtime control for scrubbing ballooned out pages
  xen/manage: don't complain about an empty value in control/sysrq node

Pull Xtensa fixes and cleanups from Max Filippov:

 - don't allocate memory in platform_setup as the memory allocator is
   not initialized at that point yet;

 - remove unnecessary ifeq KBUILD_SRC from arch/xtensa/Makefile;

 - enable SG chaining in arch/xtensa/Kconfig.

* tag 'xtensa-20180914' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: enable SG chaining in Kconfig
  xtensa: remove unnecessary KBUILD_SRC ifeq conditional
  xtensa: ISS: don't allocate memory in platform_setup

Pull arm64 fixes from Will Deacon:
 "The trickle of arm64 fixes continues to come in.

  Nothing that's the end of the world, but we've got a fix for PCI IO
  port accesses, an accidental naked "asm goto" and a fix to the
  vmcoreinfo PT_NOTE merged this time around which we'd like to get
  sorted before it becomes ABI.

   - Fix ioport_map() mapping the wrong physical address for some I/O
     BARs

   - Remove direct use of "asm goto", since some compilers don't like
     that

   - Ensure kimage_voffset is always present in vmcoreinfo PT_NOTE"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  asm-generic: io: Fix ioport_map() for !CONFIG_GENERIC_IOMAP && CONFIG_INDIRECT_PIO
  arm64: kernel: arch_crash_save_vmcoreinfo() should depend on CONFIG_CRASH_CORE
  arm64: jump_label.h: use asm_volatile_goto macro instead of "asm goto"

Add a helper for the case when the nfs4 open state has been set to use
a delegation stateid, and we want to revert to using the open stateid.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The previous fix broke recovery of delegated stateids because it assumes
that if we did not mark the delegation as suspect, then the delegation has
effectively been revoked, and so it removes that delegation irrespectively
of whether or not it is valid and still in use. While this is "mostly
harmless" for ordinary I/O, we've seen pNFS fail with LAYOUTGET spinning
in an infinite loop while complaining that we're using an invalid stateid
(in this case the all-zero stateid).

What we rather want to do here is ensure that the delegation is always
correctly marked as needing testing when that is the case. So we want
to close the loophole offered by nfs4_schedule_stateid_recovery(),
which marks the state as needing to be reclaimed, but not the
delegation that may be backing it.

Fixes: 0e3d3e5d ("NFSv4.1 fix infinite loop on IO BAD_STATEID error")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Now that the value of 'ino' can be NULL or an ERR_PTR(), we need to
change the test in the tracepoint.

Fixes: ce5624f7 ("NFSv4: Return NFS4ERR_DELAY when a layout fails...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

If someone interrupts a wait on one or more outstanding layoutgets in
pnfs_update_layout() then return the ERESTARTSYS/EINTR error.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Now that the value of 'ino' can be NULL or an ERR_PTR(), we need to
change the test in the tracepoint.

Fixes: ce5624f7 ("NFSv4: Return NFS4ERR_DELAY when a layout fails...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull dmaengine fix from Vinod Koul:
 "Fix the mic_x100_dma driver to use devm_kzalloc for driver memory, so
  that it is freed properly when it unregisters from dmaengine using
  managed API"

* tag 'dmaengine-fix-4.19-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: mic_x100_dma: use devm_kzalloc to fix an issue

Pull USB fixes from Greg KH:
 "Here are a number of small USB driver fixes for -rc4.

  The usual suspects of gadget, xhci, and dwc2/3 are in here, along with
  some reverts of reported problem changes, and a number of build
  documentation warning fixes. Full details are in the shortlog.

  All of these have been in linux-next with no reported issues"

* tag 'usb-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (28 commits)
  Revert "cdc-acm: implement put_char() and flush_chars()"
  usb: Change usb_of_get_companion_dev() place to usb/common
  usb: xhci: fix interrupt transfer error happened on MTK platforms
  usb: cdc-wdm: Fix a sleep-in-atomic-context bug in service_outstanding_interrupt()
  usb: misc: uss720: Fix two sleep-in-atomic-context bugs
  usb: host: u132-hcd: Fix a sleep-in-atomic-context bug in u132_get_frame()
  usb: Avoid use-after-free by flushing endpoints early in usb_set_interface()
  linux/mod_devicetable.h: fix kernel-doc missing notation for typec_device_id
  usb/typec: fix kernel-doc notation warning for typec_match_altmode
  usb: Don't die twice if PCI xhci host is not responding in resume
  usb: mtu3: fix error of xhci port id when enable U3 dual role
  usb: uas: add support for more quirk flags
  USB: Add quirk to support DJI CineSSD
  usb: typec: fix kernel-doc parameter warning
  usb/dwc3/gadget: fix kernel-doc parameter warning
  USB: yurex: Check for truncation in yurex_read()
  USB: yurex: Fix buffer over-read in yurex_write()
  usb: host: xhci-plat: Iterate over parent nodes for finding quirks
  xhci: Fix use after free for URB cancellation on a reallocated endpoint
  USB: add quirk for WORLDE Controller KS49 or Prodipe MIDI 49C USB controller
  ...

Pull tty fixes from Greg KH:
 "Here are three small HVC tty driver fixes to resolve a reported
  regression from 4.19-rc1.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: hvc: hvc_write() fix break condition
  tty: hvc: hvc_poll() fix read loop batching
  tty: hvc: hvc_poll() fix read loop hang

Pull staging/IIO driver fixes from Greg KH:
 "Here are a few small staging and iio driver fixes for -rc4.

  Nothing major, just a few small bugfixes for some reported issues, and
  a MAINTAINERS file update for the fbtft drivers.

  We also re-enable the building of the erofs filesystem as the XArray
  patches that were causing it to break never got merged in the -rc1
  cycle, so there's no reason it can't be turned back on for now. The
  problem that was previously there is now being handled in the Xarray
  tree at the moment, so it will not hit us again in the future.

  All of these patches have been in linux-next with no reported issues"

* tag 'staging-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: vboxvideo: Change address of scanout buffer on page-flip
  staging: vboxvideo: Fix IRQs no longer working
  staging: gasket: TODO: re-implement using UIO
  staging/fbtft: Update TODO and mailing lists
  staging: erofs: rename superblock flags (MS_xyz -> SB_xyz)
  iio: imu: st_lsm6dsx: take into account ts samples in wm configuration
  Revert "iio: temperature: maxim_thermocouple: add MAX31856 part"
  Revert "staging: erofs: disable compiling temporarile"
  MAINTAINERS: Switch a maintainer for drivers/staging/gasket
  staging: wilc1000: revert "fix TODO to compile spi and sdio components in single module"

Pull char/misc driver fixes from Greg KH:
 "Here are a small handful of char/misc driver fixes for 4.19-rc4.

  All of them are simple, resolving reported problems in a few drivers.
  Full details are in the shortlog.

  All of these have been in linux-next with no reported issues"

* tag 'char-misc-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  firmware: Fix security issue with request_firmware_into_buf()
  vmbus: don't return values for uninitalized channels
  fpga: dfl: fme: fix return value check in in pr_mgmt_init()
  misc: hmc6352: fix potential Spectre v1
  Tools: hv: Fix a bug in the key delete code
  misc: ibmvsm: Fix wrong assignment of return code
  android: binder: fix the race mmap and alloc_new_buf_locked
  mei: bus: need to unlink client before freeing
  mei: bus: fix hw module get/put balance
  mei: fix use-after-free in mei_cl_write
  mei: ignore not found client in the enumeration

This reverts commit 1f40a46c.

It turned out that this patch is not sufficient to enable PTI on 32 bit
systems with legacy 2-level page-tables. In this paging mode the huge-page
PTEs are in the top-level page-table directory, where also the mirroring to
the user-space page-table happens. So every huge PTE exits twice, in the
kernel and in the user page-table.

That means that accessed/dirty bits need to be fetched from two PTEs in
this mode to be safe, but this is not trivial to implement because it needs
changes to generic code just for the sake of enabling PTI with 32-bit
legacy paging. As all systems that need PTI should support PAE anyway,
remove support for PTI when 32-bit legacy paging is used.

Fixes: 7757d607 ('x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32')
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Link: https://lkml.kernel.org/r/1536922754-31379-1-git-send-email-joro@8bytes.org

Patch series "mmu_notifiers follow ups".

Tetsuo has noticed some fallouts from 93065ac7 ("mm, oom: distinguish
blockable mode for mmu notifiers").  One of them has been fixed and picked
up by AMD/DRM maintainer [1].  XEN issue is fixed by patch 1.  I have also
clarified expectations about blockable semantic of invalidate_range_end.
Finally the last patch removes MMU_INVALIDATE_DOES_NOT_BLOCK which is no
longer used nor needed.

[1] http://lkml.kernel.org/r/20180824135257.GU29735@dhcp22.suse.cz

This patch (of 3):

93065ac7 ("mm, oom: distinguish blockable mode for mmu notifiers") has
introduced blockable parameter to all mmu_notifiers and the notifier has
to back off when called in !blockable case and it could block down the
road.

The above commit implemented that for mn_invl_range_start but both
in_range checks are done unconditionally regardless of the blockable mode
and as such they would fail all the time for regular calls.  Fix this by
checking blockable parameter as well.

Once we are there we can remove the stale TODO.  The lock has to be
sleepable because we wait for completion down in gnttab_unmap_refs_sync.

Link: http://lkml.kernel.org/r/20180827112623.8992-2-mhocko@kernel.org
Fixes: 93065ac7 ("mm, oom: distinguish blockable mode for mmu notifiers")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

This patch removes duplicate macro useage in events_base.c.

It also fixes gcc warning:
variable ‘col’ set but not used [-Wunused-but-set-variable]
Signed-off-by: Joshua Abraham <j.abraham1776@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

The command 'xl vcpu-set 0 0', issued in dom0, will crash dom0:

BUG: unable to handle kernel NULL pointer dereference at 00000000000002d8
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 7 PID: 65 Comm: xenwatch Not tainted 4.19.0-rc2-1.ga9462db-default #1 openSUSE Tumbleweed (unreleased)
Hardware name: Intel Corporation S5520UR/S5520UR, BIOS S5500.86B.01.00.0050.050620101605 05/06/2010
RIP: e030:device_offline+0x9/0xb0
Code: 77 24 00 e9 ce fe ff ff 48 8b 13 e9 68 ff ff ff 48 8b 13 e9 29 ff ff ff 48 8b 13 e9 ea fe ff ff 90 66 66 66 66 90 41 54 55 53 <f6> 87 d8 02 00 00 01 0f 85 88 00 00 00 48 c7 c2 20 09 60 81 31 f6
RSP: e02b:ffffc90040f27e80 EFLAGS: 00010203
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8801f3800000 RSI: ffffc90040f27e70 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff820e47b3 R09: 0000000000000000
R10: 0000000000007ff0 R11: 0000000000000000 R12: ffffffff822e6d30
R13: dead000000000200 R14: dead000000000100 R15: ffffffff8158b4e0
FS:  00007ffa595158c0(0000) GS:ffff8801f39c0000(0000) knlGS:0000000000000000
CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000002d8 CR3: 00000001d9602000 CR4: 0000000000002660
Call Trace:
 handle_vcpu_hotplug_event+0xb5/0xc0
 xenwatch_thread+0x80/0x140
 ? wait_woken+0x80/0x80
 kthread+0x112/0x130
 ? kthread_create_worker_on_cpu+0x40/0x40
 ret_from_fork+0x3a/0x50

This happens because handle_vcpu_hotplug_event is called twice. In the
first iteration cpu_present is still true, in the second iteration
cpu_present is false which causes get_cpu_device to return NULL.
In case of cpu#0, cpu_online is apparently always true.

Fix this crash by checking if the cpu can be hotplugged, which is false
for a cpu that was just removed.

Also check if the cpu was actually offlined by device_remove, otherwise
leave the cpu_present state as it is.

Rearrange to code to do all work with device_hotplug_lock held.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Scrubbing pages on initial balloon down can take some time, especially
in nested virtualization case (nested EPT is slow). When HVM/PVH guest is
started with memory= significantly lower than maxmem=, all the extra
pages will be scrubbed before returning to Xen. But since most of them
weren't used at all at that point, Xen needs to populate them first
(from populate-on-demand pool). In nested virt case (Xen inside KVM)
this slows down the guest boot by 15-30s with just 1.5GB needed to be
returned to Xen.

Add runtime parameter to enable/disable it, to allow initially disabling
scrubbing, then enable it back during boot (for example in initramfs).
Such usage relies on assumption that a) most pages ballooned out during
initial boot weren't used at all, and b) even if they were, very few
secrets are in the guest at that time (before any serious userspace
kicks in).
Convert CONFIG_XEN_SCRUB_PAGES to CONFIG_XEN_SCRUB_PAGES_DEFAULT (also
enabled by default), controlling default value for the new runtime
switch.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

When guest receives a sysrq request from the host it acknowledges it by
writing '\0' to control/sysrq xenstore node. This, however, make xenstore
watch fire again but xenbus_scanf() fails to parse empty value with "%c"
format string:

 sysrq: SysRq : Emergency Sync
 Emergency Sync complete
 xen:manage: Error -34 reading sysrq code in control/sysrq

Ignore -ERANGE the same way we already ignore -ENOENT, empty value in
control/sysrq is totally legal.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

The !CONFIG_GENERIC_IOMAP version of ioport_map uses MMIO_UPPER_LIMIT to
prevent users from making I/O accesses outside the expected I/O range -
however it erroneously treats MMIO_UPPER_LIMIT as a mask which is
contradictory to its other users.

The introduction of CONFIG_INDIRECT_PIO, which subtracts an arbitrary
amount from IO_SPACE_LIMIT to form MMIO_UPPER_LIMIT, results in ioport_map
mangling the given port rather than capping it.

We address this by aligning more closely with the CONFIG_GENERIC_IOMAP
implementation of ioport_map by using the comparison operator and
returning NULL where the port exceeds MMIO_UPPER_LIMIT. Though note that
we preserve the existing behavior of masking with IO_SPACE_LIMIT such that
we don't break existing buggy drivers that somehow rely on this masking.

Fixes: 5745392e ("PCI: Apply the new generic I/O management on PCI IO hosts")
Reported-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>