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916927 commits

Author SHA1 Message Date
Davidlohr Bueso
da4ad88cab kvm: Replace vcpu->swait with rcuwait
The use of any sort of waitqueue (simple or regular) for
wait/waking vcpus has always been an overkill and semantically
wrong. Because this is per-vcpu (which is blocked) there is
only ever a single waiting vcpu, thus no need for any sort of
queue.

As such, make use of the rcuwait primitive, with the following
considerations:

  - rcuwait already provides the proper barriers that serialize
  concurrent waiter and waker.

  - Task wakeup is done in rcu read critical region, with a
  stable task pointer.

  - Because there is no concurrency among waiters, we need
  not worry about rcuwait_wait_event() calls corrupting
  the wait->task. As a consequence, this saves the locking
  done in swait when modifying the queue. This also applies
  to per-vcore wait for powerpc kvm-hv.

The x86 tscdeadline_latency test mentioned in 8577370fb0
("KVM: Use simple waitqueue for vcpu->wq") shows that, on avg,
latency is reduced by around 15-20% with this change.

Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-mips@vger.kernel.org
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-6-dave@stgolabs.net>
[Avoid extra logic changes. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:56 -04:00
Davidlohr Bueso
191a43be61 rcuwait: Introduce rcuwait_active()
This call is lockless and thus should not be trusted blindly.
For example, the return value of rcuwait_wakeup() should be used to
track whether a process was woken up.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-5-dave@stgolabs.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:54 -04:00
Davidlohr Bueso
5c21f7b322 rcuwait: Introduce prepare_to and finish_rcuwait
This allows further flexibility for some callers to implement
ad-hoc versions of the generic rcuwait_wait_event(). For example,
kvm will need this to maintain tracing semantics. The naming
is of course similar to what waitqueue apis offer.

Also go ahead and make use of rcu_assign_pointer() for both task
writes as it will make the __rcu sparse people happy - this will
be the special nil case, thus no added serialization.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-4-dave@stgolabs.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:53 -04:00
Davidlohr Bueso
9d9a6ebfea rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken
Propagating the return value of wake_up_process() back to the caller
can come in handy for future users, such as for statistics or
accounting purposes.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-3-dave@stgolabs.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:52 -04:00
Davidlohr Bueso
c9d64a1b2d rcuwait: Fix stale wake call name in comment
The 'trywake' name was renamed to simply 'wake', update the comment.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-2-dave@stgolabs.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:51 -04:00
Paolo Bonzini
c300ab9f08 KVM: x86: Replace late check_nested_events() hack with more precise fix
Add an argument to interrupt_allowed and nmi_allowed, to checking if
interrupt injection is blocked.  Use the hook to handle the case where
an interrupt arrives between check_nested_events() and the injection
logic.  Drop the retry of check_nested_events() that hack-a-fixed the
same condition.

Blocking injection is also a bit of a hack, e.g. KVM should do exiting
and non-exiting interrupt processing in a single pass, but it's a more
precise hack.  The old comment is also misleading, e.g. KVM_REQ_EVENT is
purely an optimization, setting it on every run loop (which KVM doesn't
do) should not affect functionality, only performance.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-13-sean.j.christopherson@intel.com>
[Extend to SVM, add SMI and NMI.  Even though NMI and SMI cannot come
 asynchronously right now, making the fix generic is easy and removes a
 special case. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:49 -04:00
Sean Christopherson
7ab0abdb55 KVM: VMX: Use vmx_get_rflags() to query RFLAGS in vmx_interrupt_blocked()
Use vmx_get_rflags() instead of manually reading vmcs.GUEST_RFLAGS when
querying RFLAGS.IF so that multiple checks against interrupt blocking in
a single run loop only require a single VMREAD.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-14-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:48 -04:00
Sean Christopherson
db43859280 KVM: VMX: Use vmx_interrupt_blocked() directly from vmx_handle_exit()
Use vmx_interrupt_blocked() instead of bouncing through
vmx_interrupt_allowed() when handling edge cases in vmx_handle_exit().
The nested_run_pending check in vmx_interrupt_allowed() should never
evaluate true in the VM-Exit path.

Hoist the WARN in handle_invalid_guest_state() up to vmx_handle_exit()
to enforce the above assumption for the !enable_vnmi case, and to detect
any other potential bugs with nested VM-Enter.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-12-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:47 -04:00
Sean Christopherson
3b82b8d7fd KVM: x86: WARN on injected+pending exception even in nested case
WARN if a pending exception is coincident with an injected exception
before calling check_nested_events() so that the WARN will fire even if
inject_pending_event() bails early because check_nested_events() detects
the conflict.  Bailing early isn't problematic (quite the opposite), but
suppressing the WARN is undesirable as it could mask a bug elsewhere in
KVM.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-11-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:46 -04:00
Paolo Bonzini
221e761090 KVM: nSVM: Preserve IRQ/NMI/SMI priority irrespective of exiting behavior
Short circuit vmx_check_nested_events() if an unblocked IRQ/NMI/SMI is
pending and needs to be injected into L2, priority between coincident
events is not dependent on exiting behavior.

Fixes: b518ba9fa6 ("KVM: nSVM: implement check_nested_events for interrupts")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:45 -04:00
Paolo Bonzini
fc6f7c03ad KVM: nSVM: Report interrupts as allowed when in L2 and exit-on-interrupt is set
Report interrupts as allowed when the vCPU is in L2 and L2 is being run with
exit-on-interrupts enabled and EFLAGS.IF=1 (either on the host or on the guest
according to VINTR).  Interrupts are always unblocked from L1's perspective
in this case.

While moving nested_exit_on_intr to svm.h, use INTERCEPT_INTR properly instead
of assuming it's zero (which it is of course).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:44 -04:00
Sean Christopherson
1cd2f0b0dd KVM: nVMX: Prioritize SMI over nested IRQ/NMI
Check for an unblocked SMI in vmx_check_nested_events() so that pending
SMIs are correctly prioritized over IRQs and NMIs when the latter events
will trigger VM-Exit.  This also fixes an issue where an SMI that was
marked pending while processing a nested VM-Enter wouldn't trigger an
immediate exit, i.e. would be incorrectly delayed until L2 happened to
take a VM-Exit.

Fixes: 64d6067057 ("KVM: x86: stubs for SMM support")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-10-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:43 -04:00
Sean Christopherson
15ff0b450b KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior
Short circuit vmx_check_nested_events() if an unblocked IRQ/NMI is
pending and needs to be injected into L2, priority between coincident
events is not dependent on exiting behavior.

Fixes: b6b8a1451f ("KVM: nVMX: Rework interception of IRQs and NMIs")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-9-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:42 -04:00
Paolo Bonzini
cae96af184 KVM: SVM: Split out architectural interrupt/NMI/SMI blocking checks
Move the architectural (non-KVM specific) interrupt/NMI/SMI blocking checks
to a separate helper so that they can be used in a future patch by
svm_check_nested_events().

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:40 -04:00
Sean Christopherson
1b660b6baa KVM: VMX: Split out architectural interrupt/NMI blocking checks
Move the architectural (non-KVM specific) interrupt/NMI blocking checks
to a separate helper so that they can be used in a future patch by
vmx_check_nested_events().

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-8-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:39 -04:00
Paolo Bonzini
55714cddbf KVM: nSVM: Move SMI vmexit handling to svm_check_nested_events()
Unlike VMX, SVM allows a hypervisor to take a SMI vmexit without having
any special SMM-monitor enablement sequence.  Therefore, it has to be
handled like interrupts and NMIs.  Check for an unblocked SMI in
svm_check_nested_events() so that pending SMIs are correctly prioritized
over IRQs and NMIs when the latter events will trigger VM-Exit.

Note that there is no need to test explicitly for SMI vmexits, because
guests always runs outside SMM and therefore can never get an SMI while
they are blocked.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:38 -04:00
Paolo Bonzini
bbdad0b5a7 KVM: nSVM: Report NMIs as allowed when in L2 and Exit-on-NMI is set
Report NMIs as allowed when the vCPU is in L2 and L2 is being run with
Exit-on-NMI enabled, as NMIs are always unblocked from L1's perspective
in this case.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:33 -04:00
Sean Christopherson
429ab576f3 KVM: nVMX: Report NMIs as allowed when in L2 and Exit-on-NMI is set
Report NMIs as allowed when the vCPU is in L2 and L2 is being run with
Exit-on-NMI enabled, as NMIs are always unblocked from L1's perspective
in this case.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-7-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:32 -04:00
Paolo Bonzini
a9fa7cb6aa KVM: x86: replace is_smm checks with kvm_x86_ops.smi_allowed
Do not hardcode is_smm so that all the architectural conditions for
blocking SMIs are listed in a single place.  Well, in two places because
this introduces some code duplication between Intel and AMD.

This ensures that nested SVM obeys GIF in kvm_vcpu_has_events.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:31 -04:00
Sean Christopherson
88c604b66e KVM: x86: Make return for {interrupt_nmi,smi}_allowed() a bool instead of int
Return an actual bool for kvm_x86_ops' {interrupt_nmi}_allowed() hook to
better reflect the return semantics, and to avoid creating an even
bigger mess when the related VMX code is refactored in upcoming patches.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-5-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:29 -04:00
Sean Christopherson
8081ad06b6 KVM: x86: Set KVM_REQ_EVENT if run is canceled with req_immediate_exit set
Re-request KVM_REQ_EVENT if vcpu_enter_guest() bails after processing
pending requests and an immediate exit was requested.  This fixes a bug
where a pending event, e.g. VMX preemption timer, is delayed and/or lost
if the exit was deferred due to something other than a higher priority
_injected_ event, e.g. due to a pending nested VM-Enter.  This bug only
affects the !injected case as kvm_x86_ops.cancel_injection() sets
KVM_REQ_EVENT to redo the injection, but that's purely serendipitous
behavior with respect to the deferred event.

Note, emulated preemption timer isn't the only event that can be
affected, it simply happens to be the only event where not re-requesting
KVM_REQ_EVENT is blatantly visible to the guest.

Fixes: f4124500c2 ("KVM: nVMX: Fully emulate preemption timer")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-4-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:28 -04:00
Sean Christopherson
d2060bd42e KVM: nVMX: Open a window for pending nested VMX preemption timer
Add a kvm_x86_ops hook to detect a nested pending "hypervisor timer" and
use it to effectively open a window for servicing the expired timer.
Like pending SMIs on VMX, opening a window simply means requesting an
immediate exit.

This fixes a bug where an expired VMX preemption timer (for L2) will be
delayed and/or lost if a pending exception is injected into L2.  The
pending exception is rightly prioritized by vmx_check_nested_events()
and injected into L2, with the preemption timer left pending.  Because
no window opened, L2 is free to run uninterrupted.

Fixes: f4124500c2 ("KVM: nVMX: Fully emulate preemption timer")
Reported-by: Jim Mattson <jmattson@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Shier <pshier@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-3-sean.j.christopherson@intel.com>
[Check it in kvm_vcpu_has_events too, to ensure that the preemption
 timer is serviced promptly even if the vCPU is halted and L1 is not
 intercepting HLT. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:27 -04:00
Sean Christopherson
6ce347af14 KVM: nVMX: Preserve exception priority irrespective of exiting behavior
Short circuit vmx_check_nested_events() if an exception is pending and
needs to be injected into L2, priority between coincident events is not
dependent on exiting behavior.  This fixes a bug where a single-step #DB
that is not intercepted by L1 is incorrectly dropped due to servicing a
VMX Preemption Timer VM-Exit.

Injected exceptions also need to be blocked if nested VM-Enter is
pending or an exception was already injected, otherwise injecting the
exception could overwrite an existing event injection from L1.
Technically, this scenario should be impossible, i.e. KVM shouldn't
inject its own exception during nested VM-Enter.  This will be addressed
in a future patch.

Note, event priority between SMI, NMI and INTR is incorrect for L2, e.g.
SMI should take priority over VM-Exit on NMI/INTR, and NMI that is
injected into L2 should take priority over VM-Exit INTR.  This will also
be addressed in a future patch.

Fixes: b6b8a1451f ("KVM: nVMX: Rework interception of IRQs and NMIs")
Reported-by: Jim Mattson <jmattson@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Shier <pshier@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:25 -04:00
Cathy Avery
9c3d370a8e KVM: SVM: Implement check_nested_events for NMI
Migrate nested guest NMI intercept processing
to new check_nested_events.

Signed-off-by: Cathy Avery <cavery@redhat.com>
Message-Id: <20200414201107.22952-2-cavery@redhat.com>
[Reorder clauses as NMIs have higher priority than IRQs; inject
 immediate vmexit as is now done for IRQ vmexits. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:24 -04:00
Paolo Bonzini
6e085cbfb0 KVM: SVM: immediately inject INTR vmexit
We can immediately leave SVM guest mode in svm_check_nested_events
now that we have the nested_run_pending mechanism.  This makes
things easier because we can run the rest of inject_pending_event
with GIF=0, and KVM will naturally end up requesting the next
interrupt window.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:23 -04:00
Paolo Bonzini
38c0b192bd KVM: SVM: leave halted state on vmexit
Similar to VMX, we need to leave the halted state when performing a vmexit.
Failure to do so will cause a hang after vmexit.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:22 -04:00
Paolo Bonzini
f74f94140f KVM: SVM: introduce nested_run_pending
We want to inject vmexits immediately from svm_check_nested_events,
so that the interrupt/NMI window requests happen in inject_pending_event
right after it returns.

This however has the same issue as in vmx_check_nested_events, so
introduce a nested_run_pending flag with the exact same purpose
of delaying vmexit injection after the vmentry.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:21 -04:00
Paolo Bonzini
4aef2ec902 Merge branch 'kvm-amd-fixes' into HEAD 2020-05-13 12:14:05 -04:00
Babu Moger
37486135d3 KVM: x86: Fix pkru save/restore when guest CR4.PKE=0, move it to x86.c
Though rdpkru and wrpkru are contingent upon CR4.PKE, the PKRU
resource isn't. It can be read with XSAVE and written with XRSTOR.
So, if we don't set the guest PKRU value here(kvm_load_guest_xsave_state),
the guest can read the host value.

In case of kvm_load_host_xsave_state, guest with CR4.PKE clear could
potentially use XRSTOR to change the host PKRU value.

While at it, move pkru state save/restore to common code and the
host_pkru field to kvm_vcpu_arch.  This will let SVM support protection keys.

Cc: stable@vger.kernel.org
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <158932794619.44260.14508381096663848853.stgit@naples-babu.amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 11:27:41 -04:00
Linus Torvalds
2ef96a5bb1 Linux 5.7-rc5 2020-05-10 15:16:58 -07:00
Linus Torvalds
c14cab2688 A set of fixes for x86:
- Ensure that direct mapping alias is always flushed when changing page
    attributes. The optimization for small ranges failed to do so when
    the virtual address was in the vmalloc or module space.
 
  - Unbreak the trace event registration for syscalls without arguments
    caused by the refactoring of the SYSCALL_DEFINE0() macro.
 
  - Move the printk in the TSC deadline timer code to a place where it is
    guaranteed to only be called once during boot and cannot be rearmed by
    clearing warn_once after boot. If it's invoked post boot then lockdep
    rightfully complains about a potential deadlock as the calling context
    is different.
 
  - A series of fixes for objtool and the ORC unwinder addressing variety
    of small issues:
 
      Stack offset tracking for indirect CFAs in objtool ignored subsequent
      pushs and pops
 
      Repair the unwind hints in the register clearing entry ASM code
 
      Make the unwinding in the low level exit to usermode code stop after
      switching to the trampoline stack. The unwind hint is not longer valid
      and the ORC unwinder emits a warning as it can't find the registers
      anymore.
 
      Fix the unwind hints in switch_to_asm() and rewind_stack_do_exit()
      which caused objtool to generate bogus ORC data.
 
      Prevent unwinder warnings when dumping the stack of a non-current
      task as there is no way to be sure about the validity because the
      dumped stack can be a moving target.
 
      Make the ORC unwinder behave the same way as the frame pointer
      unwinder when dumping an inactive tasks stack and do not skip the
      first frame.
 
      Prevent ORC unwinding before ORC data has been initialized
 
      Immediately terminate unwinding when a unknown ORC entry type is
      found.
 
      Prevent premature stop of the unwinder caused by IRET frames.
 
      Fix another infinite loop in objtool caused by a negative offset which
      was not catched.
 
      Address a few build warnings in the ORC unwinder and add missing
      static/ro_after_init annotations
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Merge tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:
 "A set of fixes for x86:

   - Ensure that direct mapping alias is always flushed when changing
     page attributes. The optimization for small ranges failed to do so
     when the virtual address was in the vmalloc or module space.

   - Unbreak the trace event registration for syscalls without arguments
     caused by the refactoring of the SYSCALL_DEFINE0() macro.

   - Move the printk in the TSC deadline timer code to a place where it
     is guaranteed to only be called once during boot and cannot be
     rearmed by clearing warn_once after boot. If it's invoked post boot
     then lockdep rightfully complains about a potential deadlock as the
     calling context is different.

   - A series of fixes for objtool and the ORC unwinder addressing
     variety of small issues:

       - Stack offset tracking for indirect CFAs in objtool ignored
         subsequent pushs and pops

       - Repair the unwind hints in the register clearing entry ASM code

       - Make the unwinding in the low level exit to usermode code stop
         after switching to the trampoline stack. The unwind hint is no
         longer valid and the ORC unwinder emits a warning as it can't
         find the registers anymore.

       - Fix unwind hints in switch_to_asm() and rewind_stack_do_exit()
         which caused objtool to generate bogus ORC data.

       - Prevent unwinder warnings when dumping the stack of a
         non-current task as there is no way to be sure about the
         validity because the dumped stack can be a moving target.

       - Make the ORC unwinder behave the same way as the frame pointer
         unwinder when dumping an inactive tasks stack and do not skip
         the first frame.

       - Prevent ORC unwinding before ORC data has been initialized

       - Immediately terminate unwinding when a unknown ORC entry type
         is found.

       - Prevent premature stop of the unwinder caused by IRET frames.

       - Fix another infinite loop in objtool caused by a negative
         offset which was not catched.

       - Address a few build warnings in the ORC unwinder and add
         missing static/ro_after_init annotations"

* tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/unwind/orc: Move ORC sorting variables under !CONFIG_MODULES
  x86/apic: Move TSC deadline timer debug printk
  ftrace/x86: Fix trace event registration for syscalls without arguments
  x86/mm/cpa: Flush direct map alias during cpa
  objtool: Fix infinite loop in for_offset_range()
  x86/unwind/orc: Fix premature unwind stoppage due to IRET frames
  x86/unwind/orc: Fix error path for bad ORC entry type
  x86/unwind/orc: Prevent unwinding before ORC initialization
  x86/unwind/orc: Don't skip the first frame for inactive tasks
  x86/unwind: Prevent false warnings for non-current tasks
  x86/unwind/orc: Convert global variables to static
  x86/entry/64: Fix unwind hints in rewind_stack_do_exit()
  x86/entry/64: Fix unwind hints in __switch_to_asm()
  x86/entry/64: Fix unwind hints in kernel exit path
  x86/entry/64: Fix unwind hints in register clearing code
  objtool: Fix stack offset tracking for indirect CFAs
2020-05-10 11:59:53 -07:00
Linus Torvalds
8b00083219 A single fix for objtool to prevent an infinite loop in the jump table
search which can be triggered when building the kernel with
 -ffunction-sections.
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Merge tag 'objtool-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool fix from Thomas Gleixner:
 "A single fix for objtool to prevent an infinite loop in the
  jump table search which can be triggered when building the
  kernel with '-ffunction-sections'"

* tag 'objtool-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix infinite loop in find_jump_table()
2020-05-10 11:42:14 -07:00
Linus Torvalds
bd2049f871 A single fix for the fallout of the recent futex uacess rework.
With those changes GCC9 fails to analyze arch_futex_atomic_op_inuser()
 correctly and emits a 'maybe unitialized' warning. While we usually ignore
 compiler stupidity the conditional store is pointless anyway because the
 correct case has to store. For the fault case the extra store does no harm.
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Merge tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fix from Thomas Gleixner:
 "A single fix for the fallout of the recent futex uacess rework.

  With those changes GCC9 fails to analyze arch_futex_atomic_op_inuser()
  correctly and emits a 'maybe unitialized' warning. While we usually
  ignore compiler stupidity the conditional store is pointless anyway
  because the correct case has to store. For the fault case the extra
  store does no harm"

* tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ARM: futex: Address build warning
2020-05-10 11:39:31 -07:00
Linus Torvalds
27d2dcb1b9 IOMMU Fixes for Linux v5.7-rc4
Including:
 
 	- The race condition fixes for the AMD IOMMU driver. This are 5
 	  patches fixing two race conditions around
 	  increase_address_space(). The first race condition was around
 	  the non-atomic update of the domain page-table root pointer
 	  and the variable containing the page-table depth (called
 	  mode). This is fixed now be merging page-table root and mode
 	  into one 64-bit field which is read/written atomically.
 
 	  The second race condition was around updating the page-table
 	  root pointer and making it public before the hardware caches
 	  were flushed. This could cause addresses to be mapped and
 	  returned to drivers which are not reachable by IOMMU hardware
 	  yet, causing IO page-faults. This is fixed too by adding the
 	  necessary flushes before a new page-table root is published.
 
 	  Related to the race condition fixes these patches also add a
 	  missing domain_flush_complete() barrier to update_domain() and
 	  a fix to bail out of the loop which tries to increase the
 	  address space when the call to increase_address_space() fails.
 
 	  Qian was able to trigger the race conditions under high load
 	  and memory pressure within a few days of testing. He confirmed
 	  that he has seen no issues anymore with the fixes included
 	  here.
 
 	- Fix for a list-handling bug in the VirtIO IOMMU driver.
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Merge tag 'iommu-fixes-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

Pull iommu fixes from Joerg Roedel:

 - Race condition fixes for the AMD IOMMU driver.

   These are five patches fixing two race conditions around
   increase_address_space(). The first race condition was around the
   non-atomic update of the domain page-table root pointer and the
   variable containing the page-table depth (called mode). This is fixed
   now be merging page-table root and mode into one 64-bit field which
   is read/written atomically.

   The second race condition was around updating the page-table root
   pointer and making it public before the hardware caches were flushed.
   This could cause addresses to be mapped and returned to drivers which
   are not reachable by IOMMU hardware yet, causing IO page-faults. This
   is fixed too by adding the necessary flushes before a new page-table
   root is published.

   Related to the race condition fixes these patches also add a missing
   domain_flush_complete() barrier to update_domain() and a fix to bail
   out of the loop which tries to increase the address space when the
   call to increase_address_space() fails.

   Qian was able to trigger the race conditions under high load and
   memory pressure within a few days of testing. He confirmed that he
   has seen no issues anymore with the fixes included here.

 - Fix for a list-handling bug in the VirtIO IOMMU driver.

* tag 'iommu-fixes-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/virtio: Reverse arguments to list_add
  iommu/amd: Do not flush Device Table in iommu_map_page()
  iommu/amd: Update Device Table in increase_address_space()
  iommu/amd: Call domain_flush_complete() in update_domain()
  iommu/amd: Do not loop forever when trying to increase address space
  iommu/amd: Fix race in increase_address_space()/fetch_pte()
2020-05-10 11:26:23 -07:00
Linus Torvalds
0a85ed6e7f block-5.7-2020-05-09
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Merge tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:

 - a small series fixing a use-after-free of bdi name (Christoph,Yufen)

 - NVMe fix for a regression with the smaller CQ update (Alexey)

 - NVMe fix for a hang at namespace scanning error recovery (Sagi)

 - fix race with blk-iocost iocg->abs_vdebt updates (Tejun)

* tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block:
  nvme: fix possible hang when ns scanning fails during error recovery
  nvme-pci: fix "slimmer CQ head update"
  bdi: add a ->dev_name field to struct backing_dev_info
  bdi: use bdi_dev_name() to get device name
  bdi: move bdi_dev_name out of line
  vboxsf: don't use the source name in the bdi name
  iocost: protect iocg->abs_vdebt with iocg->waitq.lock
2020-05-10 11:16:07 -07:00
Linus Torvalds
e99332e7b4 gcc-10: mark more functions __init to avoid section mismatch warnings
It seems that for whatever reason, gcc-10 ends up not inlining a couple
of functions that used to be inlined before.  Even if they only have one
single callsite - it looks like gcc may have decided that the code was
unlikely, and not worth inlining.

The code generation difference is harmless, but caused a few new section
mismatch errors, since the (now no longer inlined) function wasn't in
the __init section, but called other init functions:

   Section mismatch in reference from the function kexec_free_initrd() to the function .init.text:free_initrd_mem()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memremap()
   Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memunmap()

So add the appropriate __init annotation to make modpost not complain.
In both cases there were trivially just a single callsite from another
__init function.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 17:50:03 -07:00
Linus Torvalds
2e28f3b13a RISC-V Fixes for 5.7-rc5
This contains a smattering of fixes and cleanups that I'd like to target for
 5.7:
 
 * Dead code removal.
 * Exporting riscv_cpuid_to_hartid_mask for modules.
 * Per-CPU tracking of ISA features.
 * Setting max_pfn correctly when probing memory.
 * Adding a note to the VDSO so glibc can check the kernel's version without a
   uname().
 * A fix to force the bootloader to initialize the boot spin tables, which still
   get used as a fallback when SBI-0.1 is enabled.
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Merge tag 'riscv-for-linus-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "A smattering of fixes and cleanups:

   - Dead code removal.

   - Exporting riscv_cpuid_to_hartid_mask for modules.

   - Per-CPU tracking of ISA features.

   - Setting max_pfn correctly when probing memory.

   - Adding a note to the VDSO so glibc can check the kernel's version
     without a uname().

   - A fix to force the bootloader to initialize the boot spin tables,
     which still get used as a fallback when SBI-0.1 is enabled"

* tag 'riscv-for-linus-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Remove unused code from STRICT_KERNEL_RWX
  riscv: force __cpu_up_ variables to put in data section
  riscv: add Linux note to vdso
  riscv: set max_pfn to the PFN of the last page
  RISC-V: Remove N-extension related defines
  RISC-V: Add bitmap reprensenting ISA features common across CPUs
  RISC-V: Export riscv_cpuid_to_hartid_mask() API
2020-05-09 16:24:16 -07:00
Linus Torvalds
1a263ae60b gcc-10: avoid shadowing standard library 'free()' in crypto
gcc-10 has started warning about conflicting types for a few new
built-in functions, particularly 'free()'.

This results in warnings like:

   crypto/xts.c:325:13: warning: conflicting types for built-in function ‘free’; expected ‘void(void *)’ [-Wbuiltin-declaration-mismatch]

because the crypto layer had its local freeing functions called
'free()'.

Gcc-10 is in the wrong here, since that function is marked 'static', and
thus there is no chance of confusion with any standard library function
namespace.

But the simplest thing to do is to just use a different name here, and
avoid this gcc mis-feature.

[ Side note: gcc knowing about 'free()' is in itself not the
  mis-feature: the semantics of 'free()' are special enough that a
  compiler can validly do special things when seeing it.

  So the mis-feature here is that gcc thinks that 'free()' is some
  restricted name, and you can't shadow it as a local static function.

  Making the special 'free()' semantics be a function attribute rather
  than tied to the name would be the much better model ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 15:58:04 -07:00
Linus Torvalds
adc7192096 gcc-10: disable 'restrict' warning for now
gcc-10 now warns about passing aliasing pointers to functions that take
restricted pointers.

That's actually a great warning, and if we ever start using 'restrict'
in the kernel, it might be quite useful.  But right now we don't, and it
turns out that the only thing this warns about is an idiom where we have
declared a few functions to be "printf-like" (which seems to make gcc
pick up the restricted pointer thing), and then we print to the same
buffer that we also use as an input.

And people do that as an odd concatenation pattern, with code like this:

    #define sysfs_show_gen_prop(buffer, fmt, ...) \
        snprintf(buffer, PAGE_SIZE, "%s"fmt, buffer, __VA_ARGS__)

where we have 'buffer' as both the destination of the final result, and
as the initial argument.

Yes, it's a bit questionable.  And outside of the kernel, people do have
standard declarations like

    int snprintf( char *restrict buffer, size_t bufsz,
                  const char *restrict format, ... );

where that output buffer is marked as a restrict pointer that cannot
alias with any other arguments.

But in the context of the kernel, that 'use snprintf() to concatenate to
the end result' does work, and the pattern shows up in multiple places.
And we have not marked our own version of snprintf() as taking restrict
pointers, so the warning is incorrect for now, and gcc picks it up on
its own.

If we do start using 'restrict' in the kernel (and it might be a good
idea if people find places where it matters), we'll need to figure out
how to avoid this issue for snprintf and friends.  But in the meantime,
this warning is not useful.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 15:45:21 -07:00
Linus Torvalds
5a76021c2e gcc-10: disable 'stringop-overflow' warning for now
This is the final array bounds warning removal for gcc-10 for now.

Again, the warning is good, and we should re-enable all these warnings
when we have converted all the legacy array declaration cases to
flexible arrays. But in the meantime, it's just noise.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 15:40:52 -07:00
Sagi Grimberg
59c7c3caaa nvme: fix possible hang when ns scanning fails during error recovery
When the controller is reconnecting, the host fails I/O and admin
commands as the host cannot reach the controller. ns scanning may
revalidate namespaces during that period and it is wrong to remove
namespaces due to these failures as we may hang (see 205da24343).

One command that may fail is nvme_identify_ns_descs. Since we return
success due to having ns identify descriptor list optional, we continue
to compare ns identifiers in nvme_revalidate_disk, obviously fail and
return -ENODEV to nvme_validate_ns, which will remove the namespace.

Exactly what we don't want to happen.

Fixes: 22802bf742 ("nvme: Namepace identification descriptor list is optional")
Tested-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09 16:07:58 -06:00
Alexey Dobriyan
a8de663916 nvme-pci: fix "slimmer CQ head update"
Pre-incrementing ->cq_head can't be done in memory because OOB value
can be observed by another context.

This devalues space savings compared to original code :-\

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
	add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-32 (-32)
	Function                                     old     new   delta
	nvme_poll_irqdisable                         464     456      -8
	nvme_poll                                    455     447      -8
	nvme_irq                                     388     380      -8
	nvme_dev_disable                             955     947      -8

But the code is minimal now: one read for head, one read for q_depth,
one increment, one comparison, single instruction phase bit update and
one write for new head.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: John Garry <john.garry@huawei.com>
Tested-by: John Garry <john.garry@huawei.com>
Fixes: e2a366a4b0 ("nvme-pci: slimmer CQ head update")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09 16:07:58 -06:00
Christoph Hellwig
6bd87eec23 bdi: add a ->dev_name field to struct backing_dev_info
Cache a copy of the name for the life time of the backing_dev_info
structure so that we can reference it even after unregistering.

Fixes: 68f23b8906 ("memcg: fix a crash in wb_workfn when a device disappears")
Reported-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09 16:07:57 -06:00
Yufen Yu
d51cfc53ad bdi: use bdi_dev_name() to get device name
Use the common interface bdi_dev_name() to get device name.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Add missing <linux/backing-dev.h> include BFQ

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09 16:07:39 -06:00
Linus Torvalds
44720996e2 gcc-10: disable 'array-bounds' warning for now
This is another fine warning, related to the 'zero-length-bounds' one,
but hitting the same historical code in the kernel.

Because C didn't historically support flexible array members, we have
code that instead uses a one-sized array, the same way we have cases of
zero-sized arrays.

The one-sized arrays come from either not wanting to use the gcc
zero-sized array extension, or from a slight convenience-feature, where
particularly for strings, the size of the structure now includes the
allocation for the final NUL character.

So with a "char name[1];" at the end of a structure, you can do things
like

       v = my_malloc(sizeof(struct vendor) + strlen(name));

and avoid the "+1" for the terminator.

Yes, the modern way to do that is with a flexible array, and using
'offsetof()' instead of 'sizeof()', and adding the "+1" by hand.  That
also technically gets the size "more correct" in that it avoids any
alignment (and thus padding) issues, but this is another long-term
cleanup thing that will not happen for 5.7.

So disable the warning for now, even though it's potentially quite
useful.  Having a slew of warnings that then hide more urgent new issues
is not an improvement.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 14:52:44 -07:00
Linus Torvalds
5c45de21a2 gcc-10: disable 'zero-length-bounds' warning for now
This is a fine warning, but we still have a number of zero-length arrays
in the kernel that come from the traditional gcc extension.  Yes, they
are getting converted to flexible arrays, but in the meantime the gcc-10
warning about zero-length bounds is very verbose, and is hiding other
issues.

I missed one actual build failure because it was hidden among hundreds
of lines of warning.  Thankfully I caught it on the second go before
pushing things out, but it convinced me that I really need to disable
the new warnings for now.

We'll hopefully be all done with our conversion to flexible arrays in
the not too distant future, and we can then re-enable this warning.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 14:30:29 -07:00
Linus Torvalds
78a5255ffb Stop the ad-hoc games with -Wno-maybe-initialized
We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 13:57:10 -07:00
Linus Torvalds
1d3962ae3b io_uring-5.7-2020-05-08
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Merge tag 'io_uring-5.7-2020-05-08' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - Fix finish_wait() balancing in file cancelation (Xiaoguang)

 - Ensure early cleanup of resources in ring map failure (Xiaoguang)

 - Ensure IORING_OP_SLICE does the right file mode checks (Pavel)

 - Remove file opening from openat/openat2/statx, it's not needed and
   messes with O_PATH

* tag 'io_uring-5.7-2020-05-08' of git://git.kernel.dk/linux-block:
  io_uring: don't use 'fd' for openat/openat2/statx
  splice: move f_mode checks to do_{splice,tee}()
  io_uring: handle -EFAULT properly in io_uring_setup()
  io_uring: fix mismatched finish_wait() calls in io_uring_cancel_files()
2020-05-09 12:02:09 -07:00
Linus Torvalds
d5eeab8d7e SCSI fixes on 20200508
Four minor fixes, all in drivers (qla2xxx, ibmvfc, ibmvscsi)
 
 Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "Four minor fixes, all in drivers (qla2xxx, ibmvfc, ibmvscsi)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: ibmvscsi: Fix WARN_ON during event pool release
  scsi: ibmvfc: Don't send implicit logouts prior to NPIV login
  scsi: qla2xxx: Delete all sessions before unregister local nvme port
  scsi: qla2xxx: Fix hang when issuing nvme disconnect-all in NPIV
2020-05-08 10:36:56 -07:00
Linus Torvalds
eb24fdd8e6 Fixes for an endianness handling bug that prevented mounts on
big-endian arches, a spammy log message and a couple error paths.
 Also included a MAINTAINERS update.
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Merge tag 'ceph-for-5.7-rc5' of git://github.com/ceph/ceph-client

Pull ceph fixes from Ilya Dryomov:
 "Fixes for an endianness handling bug that prevented mounts on
  big-endian arches, a spammy log message and a couple error paths.

  Also included a MAINTAINERS update"

* tag 'ceph-for-5.7-rc5' of git://github.com/ceph/ceph-client:
  ceph: demote quotarealm lookup warning to a debug message
  MAINTAINERS: remove myself as ceph co-maintainer
  ceph: fix double unlock in handle_cap_export()
  ceph: fix special error code in ceph_try_get_caps()
  ceph: fix endianness bug when handling MDS session feature bits
2020-05-08 10:27:00 -07:00