In order to make sve_save_state()/sve_load_state() more easily
reusable and to get rid of a potential branch on context switch
critical paths, this patch makes sve_pffr() inline and moves it to
fpsimd.h.

<asm/processor.h> must be included in fpsimd.h in order to make
this work, and this creates an #include cycle that is tricky to
avoid without modifying core code, due to the way the PR_SVE_*()
prctl helpers are included in the core prctl implementation.

Instead of breaking the cycle, this patch defers inclusion of
<asm/fpsimd.h> in <asm/processor.h> until the point where it is
actually needed: i.e., immediately before the prctl definitions.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

sve_pffr(), which is used to derive the base address used for
low-level SVE save/restore routines, currently takes the relevant
task_struct as an argument.

The only accessed fields are actually part of thread_struct, so
this patch changes the argument type accordingly.  This is done in
preparation for moving this function to a header, where we do not
want to have to include <linux/sched.h> due to the consequent
circular #include problems.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Having read_zcr_features() inline in cpufeature.h results in that
header requiring #includes which make it hard to include
<asm/fpsimd.h> elsewhere without triggering header inclusion
cycles.

This is not a hot-path function and arguably should not be in
cpufeature.h in the first place, so this patch moves it to
fpsimd.c, compiled conditionally if CONFIG_ARM64_SVE=y.

This allows some SVE-related #includes to be dropped from
cpufeature.h, which will ease future maintenance.

A couple of missing #includes of <asm/fpsimd.h> are exposed by this
change under arch/arm64/.  This patch adds the missing #includes as
necessary.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This patch refactors KVM to align the host and guest FPSIMD
save/restore logic with each other for arm64.  This reduces the
number of redundant save/restore operations that must occur, and
reduces the common-case IRQ blackout time during guest exit storms
by saving the host state lazily and optimising away the need to
restore the host state before returning to the run loop.

Four hooks are defined in order to enable this:

 * kvm_arch_vcpu_run_map_fp():
   Called on PID change to map necessary bits of current to Hyp.

 * kvm_arch_vcpu_load_fp():
   Set up FP/SIMD for entering the KVM run loop (parse as
   "vcpu_load fp").

 * kvm_arch_vcpu_ctxsync_fp():
   Get FP/SIMD into a safe state for re-enabling interrupts after a
   guest exit back to the run loop.

   For arm64 specifically, this involves updating the host kernel's
   FPSIMD context tracking metadata so that kernel-mode NEON use
   will cause the vcpu's FPSIMD state to be saved back correctly
   into the vcpu struct.  This must be done before re-enabling
   interrupts because kernel-mode NEON may be used by softirqs.

 * kvm_arch_vcpu_put_fp():
   Save guest FP/SIMD state back to memory and dissociate from the
   CPU ("vcpu_put fp").

Also, the arm64 FPSIMD context switch code is updated to enable it
to save back FPSIMD state for a vcpu, not just current.  A few
helpers drive this:

 * fpsimd_bind_state_to_cpu(struct user_fpsimd_state *fp):
   mark this CPU as having context fp (which may belong to a vcpu)
   currently loaded in its registers.  This is the non-task
   equivalent of the static function fpsimd_bind_to_cpu() in
   fpsimd.c.

 * task_fpsimd_save():
   exported to allow KVM to save the guest's FPSIMD state back to
   memory on exit from the run loop.

 * fpsimd_flush_state():
   invalidate any context's FPSIMD state that is currently loaded.
   Used to disassociate the vcpu from the CPU regs on run loop exit.

These changes allow the run loop to enable interrupts (and thus
softirqs that may use kernel-mode NEON) without having to save the
guest's FPSIMD state eagerly.

Some new vcpu_arch fields are added to make all this work.  Because
host FPSIMD state can now be saved back directly into current's
thread_struct as appropriate, host_cpu_context is no longer used
for preserving the FPSIMD state.  However, it is still needed for
preserving other things such as the host's system registers.  To
avoid ABI churn, the redundant storage space in host_cpu_context is
not removed for now.

arch/arm is not addressed by this patch and continues to use its
current save/restore logic.  It could provide implementations of
the helpers later if desired.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In struct vcpu_arch, the debug_flags field is used to store
debug-related flags about the vcpu state.

Since we are about to add some more flags related to FPSIMD and
SVE, it makes sense to add them to the existing flags field rather
than adding new fields.  Since there is only one debug_flags flag
defined so far, there is plenty of free space for expansion.

In preparation for adding more flags, this patch renames the
debug_flags field to simply "flags", and updates comments
appropriately.

The flag definitions are also moved to <asm/kvm_host.h>, since
their presence in <asm/kvm_asm.h> was for purely historical
reasons:  these definitions are not used from asm any more, and not
very likely to be as more Hyp asm is migrated to C.

KVM_ARM64_DEBUG_DIRTY_SHIFT has not been used since commit
1ea66d27 ("arm64: KVM: Move away from the assembly version of
the world switch"), so this patch gets rid of that too.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
[maz: fixed minor conflict]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for optimising the way KVM manages switching the
guest and host FPSIMD state, it is necessary to provide a means for
code outside arch/arm64/kernel/fpsimd.c to restore the user trap
configuration for SVE correctly for the current task.

Rather than requiring external code to duplicate the maintenance
explicitly, this patch moves the trap maintenenace to
fpsimd_bind_to_cpu(), since it is logically part of the work of
associating the current task with the cpu.

Because fpsimd_bind_to_cpu() is rather a cryptic name to publish
alongside fpsimd_bind_state_to_cpu(), the former function is
renamed to fpsimd_bind_task_to_cpu() to make its purpose more
explicit.

This patch makes appropriate changes to ensure that
fpsimd_bind_task_to_cpu() is always called alongside
task_fpsimd_load(), so that the trap maintenance continues to be
done in every situation where it was done prior to this patch.

As a side-effect, the metadata updates done by
fpsimd_bind_task_to_cpu() now change from conditional to
unconditional in the "already bound" case of sigreturn.  This is
harmless, and a couple of extra stores on this slow path will not
impact performance.  I consider this a reasonable price to pay for
a slightly cleaner interface.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Currently the FPSIMD handling code uses the condition task->mm ==
NULL as a hint that task has no FPSIMD register context.

The ->mm check is only there to filter out tasks that cannot
possibly have FPSIMD context loaded, for optimisation purposes.
Also, TIF_FOREIGN_FPSTATE must always be checked anyway before
saving FPSIMD context back to memory.  For these reasons, the ->mm
checks are not useful, providing that TIF_FOREIGN_FPSTATE is
maintained in a consistent way for all threads.

The context switch logic is already deliberately optimised to defer
reloads of the regs until ret_to_user (or sigreturn as a special
case), and save them only if they have been previously loaded.
These paths are the only places where the wrong_task and wrong_cpu
conditions can be made false, by calling fpsimd_bind_task_to_cpu().
Kernel threads by definition never reach these paths.  As a result,
the wrong_task and wrong_cpu tests in fpsimd_thread_switch() will
always yield true for kernel threads.

This patch removes the redundant checks and special-case code,
ensuring that TIF_FOREIGN_FPSTATE is set whenever a kernel thread
is scheduled in, and ensures that this flag is set for the init
task.  The fpsimd_flush_task_state() call already present in
copy_thread() ensures the same for any new task.

With TIF_FOREIGN_FPSTATE always set for kernel threads, this patch
ensures that no extra context save work is added for kernel
threads, and eliminates the redundant context saving that may
currently occur for kernel threads that have acquired an mm via
use_mm().
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The init task is started with thread_flags equal to 0, which means
that TIF_FOREIGN_FPSTATE is initially clear.

It is theoretically possible (if unlikely) that the init task could
reach userspace without ever being scheduled out.  If this occurs,
data left in the FPSIMD registers by the kernel could be exposed.

This patch fixes this anomaly by ensuring that the init task's
initial TIF_FOREIGN_FPSTATE is set.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Fixes: 005f78cd ("arm64: defer reloading a task's FPSIMD state to userland resume")
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

In preparation for allowing non-task (i.e., KVM vcpu) FPSIMD
contexts to be handled by the fpsimd common code, this patch adapts
task_fpsimd_save() to save back the currently loaded context,
removing the explicit dependency on current.

The relevant storage to write back to in memory is now found by
examining the fpsimd_last_state percpu struct.

fpsimd_save() does nothing unless TIF_FOREIGN_FPSTATE is clear, and
fpsimd_last_state is updated under local_bh_disable() or
local_irq_disable() everywhere that TIF_FOREIGN_FPSTATE is cleared:
thus, fpsimd_save() will write back to the correct storage for the
loaded context.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

To make the lazy FPSIMD context switch trap code easier to hack on,
this patch converts it to C.

This is not amazingly efficient, but the trap should typically only
be taken once per host context switch.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

KVM/ARM differs from other architectures in having to maintain an
additional virtual address space from that of the host and the
guest, because we split the execution of KVM across both EL1 and
EL2.

This results in a need to explicitly map data structures into EL2
(hyp) which are accessed from the hyp code.  As we are about to be
more clever with our FPSIMD handling on arm64, which stores data in
the task struct and uses thread_info flags, we will have to map
parts of the currently executing task struct into the EL2 virtual
address space.

However, we don't want to do this on every KVM_RUN, because it is a
fairly expensive operation to walk the page tables, and the common
execution mode is to map a single thread to a VCPU.  By introducing
a hook that architectures can select with
HAVE_KVM_VCPU_RUN_PID_CHANGE, we do not introduce overhead for
other architectures, but have a simple way to only map the data we
need when required for arm64.

This patch introduces the framework only, and wires it up in the
arm/arm64 KVM common code.

No functional change.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This patch uses the new update_thread_flag() helpers to simplify a
couple of if () set; else clear; constructs.

No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

There are a number of bits of code sprinkled around the kernel to
set a thread flag if a certain condition is true, and clear it
otherwise.

To help make those call sites terser and less cumbersome, this
patch adds a new family of thread flag manipulators

	update*_thread_flag([...,] flag, cond)

which do the equivalent of:

	if (cond)
		set*_thread_flag([...,] flag);
	else
		clear*_thread_flag([...,] flag);
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

fpsimd_last_state.st is set to NULL as a way of indicating that
current's FPSIMD registers are no longer loaded in the cpu.  In
particular, this is done when the kernel temporarily uses or
clobbers the FPSIMD registers for its own purposes, as in CPU PM or
kernel-mode NEON, resulting in them being populated with garbage
data not belonging to a task.

Commit 17eed27b ("arm64/sve: KVM: Prevent guests from using
SVE") factors this operation out as a new helper
fpsimd_flush_cpu_state() to make it clearer what is being done
here, and on SVE systems this helper is now used, via
kvm_fpsimd_flush_cpu_state(), to invalidate the registers after KVM
has run a vcpu.  The reason for this is that KVM does not yet
understand how to restore the full host SVE registers itself after
loading the guest FPSIMD context into them.

This exposes a particular problem: if fpsimd_last_state.st is set
to NULL without also setting TIF_FOREIGN_FPSTATE, the kernel may
continue to think that current's FPSIMD registers are live even
though they have actually been clobbered.

Prior to the aforementioned commit, the only path where
fpsimd_last_state.st is set to NULL without setting
TIF_FOREIGN_FPSTATE is when kernel_neon_begin() is called by a
kernel thread (where current->mm can be NULL).  This does not
matter, because the only harm is that at context-switch time
fpsimd_thread_switch() may unnecessarily save the FPSIMD registers
back to current's thread_struct (even though kernel threads are not
considered to have any FPSIMD context of their own and the
registers will never be reloaded).

Note that although CPU_PM_ENTER lacks the TIF_FOREIGN_FPSTATE
setting, every CPU passing through that path must subsequently pass
through CPU_PM_EXIT before it can re-enter the kernel proper.
CPU_PM_EXIT sets the flag.

The sve_flush_cpu_state() function added by commit 17eed27b
also lacks the proper maintenance of TIF_FOREIGN_FPSTATE.  This may
cause the bits of a host task's SVE registers that do not alias the
FPSIMD register file to spontaneously appear zeroed if a KVM vcpu
runs in the same task in the meantime.  Although this effect is
hidden by the fact that the non-FPSIMD bits of the SVE registers
are zeroed by a syscall anyway, it is doubtless a bad idea to rely
on these different code paths interacting correctly under future
maintenance.

This patch makes TIF_FOREIGN_FPSTATE an unconditional side-effect
of fpsimd_flush_cpu_state(), and removes the set_thread_flag()
calls that become redundant as a result.  This ensures that
TIF_FOREIGN_FPSTATE cannot remain clear if the FPSIMD state in the
FPSIMD registers is invalid.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

For historical reasons, we open-code lm_alias() in kvm_ksym_ref().

Let's use lm_alias() to avoid duplication and make things clearer.

As we have to pull this from <linux/mm.h> (which is not safe for
inclusion in assembly), we may as well move the kvm_ksym_ref()
definition into the existing !__ASSEMBLY__ block.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Pll KVM fixes from Radim Krčmář:
 "ARM:
   - Fix proxying of GICv2 CPU interface accesses
   - Fix crash when switching to BE
   - Track source vcpu git GICv2 SGIs
   - Fix an outdated bit of documentation

  x86:
   - Speed up injection of expired timers (for stable)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: remove APIC Timer periodic/oneshot spikes
  arm64: vgic-v2: Fix proxying of cpuif access
  KVM: arm/arm64: vgic_init: Cleanup reference to process_maintenance
  KVM: arm64: Fix order of vcpu_write_sys_reg() arguments
  KVM: arm/arm64: vgic: Fix source vcpu issues for GICv2 SGI

Pull iommu fixes from Joerg Roedel:

 - fix a compile warning in the AMD IOMMU driver with irq remapping
   disabled

 - fix for VT-d interrupt remapping and invalidation size (caused a
   BUG_ON when trying to invalidate more than 4GB)

 - build fix and a regression fix for broken graphics with old DTS for
   the rockchip iommu driver

 - a revert in the PCI window reservation code which fixes a regression
   with VFIO.

* tag 'iommu-fixes-v4.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu: rockchip: fix building without CONFIG_OF
  iommu/vt-d: Use WARN_ON_ONCE instead of BUG_ON in qi_flush_dev_iotlb()
  iommu/vt-d: fix shift-out-of-bounds in bug checking
  iommu/dma: Move PCI window region reservation back into dma specific path.
  iommu/rockchip: Make clock handling optional
  iommu/amd: Hide unused iommu_table_lock
  iommu/vt-d: Fix usage of force parameter in intel_ir_reconfigure_irte()

Pull x86 fix from Thomas Gleixner:
 "Unbreak the CPUID CPUID_8000_0008_EBX reload which got dropped when
  the evaluation of physical and virtual bits which uses the same CPUID
  leaf was moved out of get_cpu_cap()"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Restore CPUID_8000_0008_EBX reload

Pull clocksource fixes from Thomas Gleixner:
 "The recent addition of the early TSC clocksource breaks on machines
  which have an unstable TSC because in case that TSC is disabled, then
  the clocksource selection logic falls back to the early TSC which is
  obviously bogus.

  That also unearthed a few robustness issues in the clocksource
  derating code which are addressed as well"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Rework stale comment
  clocksource: Consistent de-rate when marking unstable
  x86/tsc: Fix mark_tsc_unstable()
  clocksource: Initialize cs->wd_list
  clocksource: Allow clocksource_mark_unstable() on unregistered clocksources
  x86/tsc: Always unregister clocksource_tsc_early

Pull irq fix from Thomas Gleixner:
 "A single fix to prevent false positives in the spurious interrupt
  detector when more than a single demultiplex register is evaluated in
  the Qualcom irq combiner driver"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/qcom: Fix check for spurious interrupts

Pull x86 platform driver fixes from Darren Hart:

 - We missed a case in the Dell config dependencies resulting in a
   possible bad configuration, resolve it by giving up on trying to keep
   DELL_LAPTOP visible in the menu and make it depend on DELL_SMBIOS.

 - Fix a null pointer dereference at module unload for the asus-wireless
   driver.

* tag 'platform-drivers-x86-v4.17-2' of git://git.infradead.org/linux-platform-drivers-x86:
  platform/x86: Kconfig: Fix dell-laptop dependency chain.
  platform/x86: asus-wireless: Fix NULL pointer dereference

Pull USB fixes from Greg KH:
 "Here are some USB driver fixes for 4.17-rc4.

  The majority of them are some USB gadget fixes that missed my last
  pull request. The "largest" patch in here is a fix for the old visor
  driver that syzbot found 6 months or so ago and I finally remembered
  to fix it.

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

* tag 'usb-4.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  Revert "usb: host: ehci: Use dma_pool_zalloc()"
  usb: typec: tps6598x: handle block reads separately with plain-I2C adapters
  usb: typec: tcpm: Release the role mux when exiting
  USB: Accept bulk endpoints with 1024-byte maxpacket
  xhci: Fix use-after-free in xhci_free_virt_device
  USB: serial: visor: handle potential invalid device configuration
  USB: serial: option: adding support for ublox R410M
  usb: musb: trace: fix NULL pointer dereference in musb_g_tx()
  usb: musb: host: fix potential NULL pointer dereference
  usb: gadget: composite Allow for larger configuration descriptors
  usb: dwc3: gadget: Fix list_del corruption in dwc3_ep_dequeue
  usb: dwc3: gadget: dwc3_gadget_del_and_unmap_request() can be static
  usb: dwc2: pci: Fix error return code in dwc2_pci_probe()
  usb: dwc2: WA for Full speed ISOC IN in DDMA mode.
  usb: dwc2: dwc2_vbus_supply_init: fix error check
  usb: gadget: f_phonet: fix pn_net_xmit()'s return type

Since the commit "8003c9ae: add APIC Timer periodic/oneshot mode VMX
preemption timer support", a Windows 10 guest has some erratic timer
spikes.

Here the results on a 150000 times 1ms timer without any load:
	  Before 8003c9ae | After 8003c9ae
Max           1834us          |  86000us
Mean          1100us          |   1021us
Deviation       59us          |    149us
Here the results on a 150000 times 1ms timer with a cpu-z stress test:
	  Before 8003c9ae | After 8003c9ae
Max          32000us          | 140000us
Mean          1006us          |   1997us
Deviation      140us          |  11095us

The root cause of the problem is starting hrtimer with an expiry time
already in the past can take more than 20 milliseconds to trigger the
timer function.  It can be solved by forward such past timers
immediately, rather than submitting them to hrtimer_start().
In case the timer is periodic, update the target expiration and call
hrtimer_start with it.

v2: Check if the tsc deadline is already expired. Thank you Mika.
v3: Execute the past timers immediately rather than submitting them to
hrtimer_start().
v4: Rearm the periodic timer with advance_periodic_target_expiration() a
simpler version of set_target_expiration(). Thank you Paolo.

Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Anthoine Bourgeois <anthoine.bourgeois@blade-group.com>
8003c9ae ("KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM/arm fixes for 4.17, take #2

- Fix proxying of GICv2 CPU interface accesses
- Fix crash when switching to BE
- Track source vcpu git GICv2 SGIs
- Fix an outdated bit of documentation

Merge tag 'kbuild-fixes-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - remove state comment in modpost

 - extend MAINTAINERS entry to cover modpost and more makefiles

 - fix missed building of SANCOV gcc-plugin

 - replace left-over 'bison' with $(YACC)

 - display short log when generating parer of genksyms

* tag 'kbuild-fixes-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  genksyms: fix typo in parse.tab.{c,h} generation rules
  kbuild: replace hardcoded bison in cmd_bison_h with $(YACC)
  gcc-plugins: fix build condition of SANCOV plugin
  MAINTAINERS: Update Kbuild entry with a few paths
  modpost: delete stale comment

Pull clk fixes froom Stephen Boyd:
 "A handful of fixes for the stm32mp1 clk driver came in during the
  merge window for the driver that got merged in the merge window.

  Plus a warning fix for unused PM ops and a couple fixes for the meson
  clk driver clk names that went unnoticed with the regmap rework.

  There's also another fix in here for the mux rounding flag which
  wasn't doing what it said it did, but now it does"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: meson: meson8b: fix meson8b_cpu_clk parent clock name
  clk: meson: meson8b: fix meson8b_fclk_div3_div clock name
  clk: meson: drop meson_aoclk_gate_regmap_ops
  clk: meson: honor CLK_MUX_ROUND_CLOSEST in clk_regmap
  clk: honor CLK_MUX_ROUND_CLOSEST in generic clk mux
  clk: cs2000: mark resume function as __maybe_unused
  clk: stm32mp1: remove ck_apb_dbg clock
  clk: stm32mp1: set stgen_k clock as critical
  clk: stm32mp1: add missing tzc2 clock
  clk: stm32mp1: fix SAI3 & SAI4 clocks
  clk: stm32mp1: remove unused dfsdm_src[] const
  clk: stm32mp1: add missing static

Pull remoteproc and rpmsg fixes from Bjorn Andersson:

 - fix screw-up when reversing boolean for rproc_stop()

 - add missing OF node refcounting dereferences

 - add missing MODULE_ALIAS in rpmsg_char

* tag 'rproc-v4.17-1' of git://github.com/andersson/remoteproc:
  rpmsg: added MODULE_ALIAS for rpmsg_char
  remoteproc: qcom: Fix potential device node leaks
  remoteproc: fix crashed parameter logic on stop call

Pull drm fixes from Dave Airlie:
 "vmwgfx, i915, vc4, vga dac fixes.

  This seems eerily quiet, so I expect it will explode next week or
  something.

  One i915 model firmware, two vmwgfx fixes, one vc4 fix and one bridge
  leak fix"

* tag 'drm-fixes-for-v4.17-rc4' of git://people.freedesktop.org/~airlied/linux:
  drm/bridge: vga-dac: Fix edid memory leak
  drm/vc4: Make sure vc4_bo_{inc,dec}_usecnt() calls are balanced
  drm/i915/glk: Add MODULE_FIRMWARE for Geminilake
  drm/vmwgfx: Fix a buffer object leak
  drm/vmwgfx: Clean up fbdev modeset locking

Pull tracing fixes from Steven Rostedt:
 "Some of the files in the tracing directory show file mode 0444 when
  they are writable by root. To fix the confusion, they should be 0644.
  Note, either case root can still write to them.

  Zhengyuan asked why I never applied that patch (the first one is from
  2014!). I simply forgot about it. /me lowers head in shame"

* tag 'trace-v4.17-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix the file mode of stack tracer
  ftrace: Have set_graph_* files have normal file modes

Pull rdma fixes from Doug Ledford:
 "This is our first pull request of the rc cycle. It's not that it's
  been overly quiet, we were just waiting on a few things before sending
  this off.

  For instance, the 6 patch series from Intel for the hfi1 driver had
  actually been pulled in on Tuesday for a Wednesday pull request, only
  to have Jason notice something I missed, so we held off for some
  testing, and then on Thursday had to respin the series because the
  very first patch needed a minor fix (unnecessary cast is all).

  There is a sizable hns patch series in here, as well as a reasonably
  largish hfi1 patch series, then all of the lines of uapi updates are
  just the change to the new official Linux-OpenIB SPDX tag (a bunch of
  our files had what amounts to a BSD-2-Clause + MIT Warranty statement
  as their license as a result of the initial code submission years ago,
  and the SPDX folks decided it was unique enough to warrant a unique
  tag), then the typical mlx4 and mlx5 updates, and finally some cxgb4
  and core/cache/cma updates to round out the bunch.

  None of it was overly large by itself, but in the 2 1/2 weeks we've
  been collecting patches, it has added up :-/.

  As best I can tell, it's been through 0day (I got a notice about my
  last for-next push, but not for my for-rc push, but Jason seems to
  think that failure messages are prioritized and success messages not
  so much). It's also been through linux-next. And yes, we did notice in
  the context portion of the CMA query gid fix patch that there is a
  dubious BUG_ON() in the code, and have plans to audit our BUG_ON usage
  and remove it anywhere we can.

  Summary:

   - Various build fixes (USER_ACCESS=m and ADDR_TRANS turned off)

   - SPDX license tag cleanups (new tag Linux-OpenIB)

   - RoCE GID fixes related to default GIDs

   - Various fixes to: cxgb4, uverbs, cma, iwpm, rxe, hns (big batch),
     mlx4, mlx5, and hfi1 (medium batch)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (52 commits)
  RDMA/cma: Do not query GID during QP state transition to RTR
  IB/mlx4: Fix integer overflow when calculating optimal MTT size
  IB/hfi1: Fix memory leak in exception path in get_irq_affinity()
  IB/{hfi1, rdmavt}: Fix memory leak in hfi1_alloc_devdata() upon failure
  IB/hfi1: Fix NULL pointer dereference when invalid num_vls is used
  IB/hfi1: Fix loss of BECN with AHG
  IB/hfi1 Use correct type for num_user_context
  IB/hfi1: Fix handling of FECN marked multicast packet
  IB/core: Make ib_mad_client_id atomic
  iw_cxgb4: Atomically flush per QP HW CQEs
  IB/uverbs: Fix kernel crash during MR deregistration flow
  IB/uverbs: Prevent reregistration of DM_MR to regular MR
  RDMA/mlx4: Add missed RSS hash inner header flag
  RDMA/hns: Fix a couple misspellings
  RDMA/hns: Submit bad wr
  RDMA/hns: Update assignment method for owner field of send wqe
  RDMA/hns: Adjust the order of cleanup hem table
  RDMA/hns: Only assign dqpn if IB_QP_PATH_DEST_QPN bit is set
  RDMA/hns: Remove some unnecessary attr_mask judgement
  RDMA/hns: Only assign mtu if IB_QP_PATH_MTU bit is set
  ...

Pull block fixes from Jens Axboe:
 "A collection of fixes that should to into this release. This contains:

   - Set of bcache fixes from Coly, fixing regression in patches that
     went into this series.

   - Set of NVMe fixes by way of Keith.

   - Set of bdi related fixes, one from Jan and two from Tetsuo Handa,
     fixing various issues around device addition/removal.

   - Two block inflight fixes from Omar, fixing issues around the
     transition to using tags for blk-mq inflight accounting that we
     did a few releases ago"

* tag 'for-linus-20180504' of git://git.kernel.dk/linux-block:
  bdi: Fix oops in wb_workfn()
  nvmet: switch loopback target state to connecting when resetting
  nvme/multipath: Fix multipath disabled naming collisions
  nvme/multipath: Disable runtime writable enabling parameter
  nvme: Set integrity flag for user passthrough commands
  nvme: fix potential memory leak in option parsing
  bdi: Fix use after free bug in debugfs_remove()
  bdi: wake up concurrent wb_shutdown() callers.
  bcache: use pr_info() to inform duplicated CACHE_SET_IO_DISABLE set
  bcache: set dc->io_disable to true in conditional_stop_bcache_device()
  bcache: add wait_for_kthread_stop() in bch_allocator_thread()
  bcache: count backing device I/O error for writeback I/O
  bcache: set CACHE_SET_IO_DISABLE in bch_cached_dev_error()
  bcache: store disk name in struct cache and struct cached_dev
  blk-mq: fix sysfs inflight counter
  blk-mq: count allocated but not started requests in iostats inflight

Pull xfs fixes from Darrick Wong:
 "I've got one more bug fix for xfs for 4.17-rc4, which caps the amount
  of data we try to handle in one dedupe request so that userspace can't
  livelock the kernel.

  This series has been run through a full xfstests run during the week
  and through a quick xfstests run against this morning's master, with
  no ajor failures reported.

  Summary:

  - Cap the maximum length of a deduplication request at MAX_RW_COUNT/2
    to avoid kernel livelock due to excessively large IO requests"

* tag 'xfs-4.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: cap the length of deduplication requests

Pull btrfs fixes from David Sterba:
 "Two regression fixes and one fix for stable"

* tag 'for-4.17-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: send, fix missing truncate for inode with prealloc extent past eof
  btrfs: Take trans lock before access running trans in check_delayed_ref
  btrfs: Fix wrong first_key parameter in replace_path

'quet' is replaced by 'quiet' in scripts/genksyms/Makefile
Signed-off-by: Mauro Rossi <issor.oruam@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Commit 73a4f6db ("kbuild: add LEX and YACC variables") missed to
update cmd_bison_h somehow.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Since commit d677a4d6 ("Makefile: support flag
-fsanitizer-coverage=trace-cmp"), you miss to build the SANCOV
plugin under some circumstances.

  CONFIG_KCOV=y
  CONFIG_KCOV_ENABLE_COMPARISONS=y
  Your compiler does not support -fsanitize-coverage=trace-pc
  Your compiler does not support -fsanitize-coverage=trace-cmp

Under this condition, $(CFLAGS_KCOV) is not empty but contains a
space, so the following ifeq-conditional is false.

    ifeq ($(CFLAGS_KCOV),)

Then, scripts/Makefile.gcc-plugins misses to add sancov_plugin.so to
gcc-plugin-y while the SANCOV plugin is necessary as an alternative
means.

Fixes: d677a4d6 ("Makefile: support flag -fsanitizer-coverage=trace-cmp")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>

I managed to send some modpost patches to old addresses of both
Masahiro and Michal, and omitted linux-kbuild from cc, because my
tried and trusted scripts/get_maintainer wrapper failed me. Add the
modpost directory to the MAINTAINERS entry, and while at it make the
Makefile glob match scripts/Makefile itself, and add one matching the
Kbuild.include file as well.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Merge tag 'usb-serial-4.17-rc4' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus

Johan writes:

USB-serial fixes for v4.17-rc4

Here's a fix for a long-standing issue in the visor driver, which could
have security implications. Included is also a new modem device id.

Both commits have been in linux-next for a couple of days with no
reported issues.
Signed-off-by: Johan Hovold <johan@kernel.org>

This reverts commit 22072e83 as it is
broken.

Alan writes:
	What you can't see just from reading the patch is that in both
	cases (ehci->itd_pool and ehci->sitd_pool) there are two
	allocation paths -- the two branches of an "if" statement -- and
	only one of the paths calls dma_pool_[z]alloc.  However, the
	memset is needed for both paths, and so it can't be eliminated.
	Given that it must be present, there's no advantage to calling
	dma_pool_zalloc rather than dma_pool_alloc.
Reported-by: Erick Cafferata <erick@cafferata.me>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>