Commit 11988499 ("KVM: x86: Skip EFER vs. guest CPUID checks for
host-initiated writes", 2019-04-02) introduced a "return false" in a
function returning int, and anyway set_efer has a "nonzero on error"
conventon so it should be returning 1.
Reported-by: Pavel Machek <pavel@denx.de>
Fixes: 11988499 ("KVM: x86: Skip EFER vs. guest CPUID checks for host-initiated writes")
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The fields filter would not work with child fields, as the respective
parents would not be included. No parents displayed == no childs displayed.
To reproduce, run on s390 (would work on other platforms, too, but would
require a different filter name):
- Run 'kvm_stat -d'
- Press 'f'
- Enter 'instruct'
Notice that events like instruction_diag_44 or instruction_diag_500 are not
displayed - the output remains empty.
With this patch, we will filter by matching events and their parents.
However, consider the following example where we filter by
instruction_diag_44:

  kvm statistics - summary
                   regex filter: instruction_diag_44
   Event                                         Total %Total CurAvg/s
   exit_instruction                                276  100.0       12
     instruction_diag_44                           256   92.8       11
   Total                                           276              12

Note that the parent ('exit_instruction') displays the total events, but
the childs listed do not match its total (256 instead of 276). This is
intended (since we're filtering all but one child), but might be confusing
on first sight.
Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

struct kvm_nested_state is only available on x86 so far. To be able
to compile the code on other architectures as well, we need to wrap
the related code with #ifdefs.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

aarch64 fixups needed to compile with warnings as errors.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

VM_MODE_P52V48_4K is not a valid mode for AArch64. Replace its
use in vm_create_default() with a mode that works and represents
a good AArch64 default. (We didn't ever see a problem with this
because we don't have any unit tests using vm_create_default(),
but it's good to get it fixed in advance.)
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The memory slot size must be aligned to the host's page size. When
testing a guest with a 4k page size on a host with a 64k page size,
then 3 guest pages are not host page size aligned. Since we just need
a nearly arbitrary number of extra pages to ensure the memslot is not
aligned to a 64 host-page boundary for this test, then we can use
16, as that's 64k aligned, but not 64 * 64k aligned.

Fixes: 76d58e0f ("KVM: fix KVM_CLEAR_DIRTY_LOG for memory slots of unaligned size", 2019-04-17)
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kselftests exposed a problem in the s390 handling for memory slots.
Right now we only do proper memory slot handling for creation of new
memory slots. Neither MOVE, nor DELETION are handled properly. Let us
implement those.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

According to the SDM, for MSR_IA32_PERFCTR0/1 "the lower-order 32 bits of
each MSR may be written with any value, and the high-order 8 bits are
sign-extended according to the value of bit 31", but the fixed counters
in real hardware are limited to the width of the fixed counters ("bits
beyond the width of the fixed-function counter are reserved and must be
written as zeros").  Fix KVM to do the same.
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This patch will simplify the changes in the next, by enforcing the
masking of the counters to RDPMC and RDMSR.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

After commit:

  672ff6cf ("KVM: x86: Raise #GP when guest vCPU do not support PMU")

my AMD guests started #GPing like this:

  general protection fault: 0000 [#1] PREEMPT SMP
  CPU: 1 PID: 4355 Comm: bash Not tainted 5.1.0-rc6+ #3
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
  RIP: 0010:x86_perf_event_update+0x3b/0xa0

with Code: pointing to RDPMC. It is RDPMC because the guest has the
hardware watchdog CONFIG_HARDLOCKUP_DETECTOR_PERF enabled which uses
perf. Instrumenting kvm_pmu_rdpmc() some, showed that it fails due to:

  if (!pmu->version)
  	return 1;

which the above commit added. Since AMD's PMU leaves the version at 0,
that causes the #GP injection into the guest.

Set pmu->version arbitrarily to 1 and move it above the non-applicable
struct kvm_pmu members.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Cc: kvm@vger.kernel.org
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Mihai Carabas <mihai.carabas@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
Fixes: 672ff6cf ("KVM: x86: Raise #GP when guest vCPU do not support PMU")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Userspace can easily set up invalid processor state in such a way that
dmesg will be filled with VMCS or VMCB dumps.  Disable this by default
using a module parameter.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When assigning kvm irqfd we didn't check the irqchip mode but we allow
KVM_IRQFD to succeed with all the irqchip modes.  However it does not
make much sense to create irqfd even without the kernel chips.  Let's
provide a arch-dependent helper to check whether a specific irqfd is
allowed by the arch.  At least for x86, it should make sense to check:

- when irqchip mode is NONE, all irqfds should be disallowed, and,

- when irqchip mode is SPLIT, irqfds that are with resamplefd should
  be disallowed.

For either of the case, previously we'll silently ignore the irq or
the irq ack event if the irqchip mode is incorrect.  However that can
cause misterious guest behaviors and it can be hard to triage.  Let's
fail KVM_IRQFD even earlier to detect these incorrect configurations.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Radim Krčmář <rkrcmar@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Current logic does not allow VCPU to be loaded onto CPU with
APIC ID 255. This should be allowed since the host physical APIC ID
field in the AVIC Physical APIC table entry is an 8-bit value,
and APIC ID 255 is valid in system with x2APIC enabled.
Instead, do not allow VCPU load if the host APIC ID cannot be
represented by an 8-bit value.

Also, use the more appropriate AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK
instead of AVIC_MAX_PHYSICAL_ID_COUNT.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The guest_code of sync_regs_test is assuming that the compiler will not
touch %r11 outside the asm that increments it, which is a bit brittle.
Instead, we can increment a variable and use a dummy asm to ensure the
increment is not optimized away.  However, we also need to use a
callee-save register or the compiler will insert a save/restore around
the vmexit, breaking the whole idea behind the test.

(Yes, "if it ain't broken...", but I would like the test to be clean
before it is copied into the upcoming s390 selftests).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The check for entry->index == 0 is done twice. One time should
be sufficient.
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Expose per-vCPU timer_advance_ns to userspace, so it is able to
query the auto-adjusted value.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

After commit c3941d9e (KVM: lapic: Allow user to disable adaptive tuning of
timer advancement), '-1' enables adaptive tuning starting from default
advancment of 1000ns. However, we should expose an int instead of an overflow
uint module parameter.

Before patch:

/sys/module/kvm/parameters/lapic_timer_advance_ns:4294967295

After patch:

/sys/module/kvm/parameters/lapic_timer_advance_ns:-1

Fixes: c3941d9e (KVM: lapic: Allow user to disable adaptive tuning of timer advancement)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

We get a warning when build kernel W=1:
arch/x86/kvm/vmx/vmx.c:6365:6: warning: no previous prototype for ‘vmx_update_host_rsp’ [-Wmissing-prototypes]
 void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)

Add the missing declaration to fix this.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

 BUG: using __this_cpu_read() in preemptible [00000000] code: qemu-system-x86/4590
  caller is nested_vmx_enter_non_root_mode+0xebd/0x1790 [kvm_intel]
  CPU: 4 PID: 4590 Comm: qemu-system-x86 Tainted: G           OE     5.1.0-rc4+ #1
  Call Trace:
   dump_stack+0x67/0x95
   __this_cpu_preempt_check+0xd2/0xe0
   nested_vmx_enter_non_root_mode+0xebd/0x1790 [kvm_intel]
   nested_vmx_run+0xda/0x2b0 [kvm_intel]
   handle_vmlaunch+0x13/0x20 [kvm_intel]
   vmx_handle_exit+0xbd/0x660 [kvm_intel]
   kvm_arch_vcpu_ioctl_run+0xa2c/0x1e50 [kvm]
   kvm_vcpu_ioctl+0x3ad/0x6d0 [kvm]
   do_vfs_ioctl+0xa5/0x6e0
   ksys_ioctl+0x6d/0x80
   __x64_sys_ioctl+0x1a/0x20
   do_syscall_64+0x6f/0x6c0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Accessing per-cpu variable should disable preemption, this patch extends the
preemption disable region for __this_cpu_read().

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Fixes: 52017608 ("KVM: nVMX: add option to perform early consistency checks via H/W")
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

s390 does not have memremap, even though in this particular case it
would be useful.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Kvm now supports extended CPUID functions through 0x8000001f.  CPUID
leaf 0x8000001e is AMD's Processor Topology Information leaf. This
contains similar information to CPUID leaf 0xb (Intel's Extended
Topology Enumeration leaf), and should be included in the output of
KVM_GET_SUPPORTED_CPUID, even though userspace is likely to override
some of this information based upon the configuration of the
particular VM.

Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Fixes: 8765d753 ("KVM: X86: Extend CPUID range to include new leaf")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Per the APM, "CPUID Fn8000_001D_E[D,C,B,A]X reports cache topology
information for the cache enumerated by the value passed to the
instruction in ECX, referred to as Cache n in the following
description. To gather information for all cache levels, software must
repeatedly execute CPUID with 8000_001Dh in EAX and ECX set to
increasing values beginning with 0 until a value of 00h is returned in
the field CacheType (EAX[4:0]) indicating no more cache descriptions
are available for this processor."

The termination condition is the same as leaf 4, so we can reuse that
code block for leaf 0x8000001d.

Fixes: 8765d753 ("KVM: X86: Extend CPUID range to include new leaf")
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

So far the KVM selftests are compiled without any compiler warnings
enabled. That's quite bad, since we miss a lot of possible bugs this
way. Let's enable at least "-Wall" and some other useful warning flags
now, and fix at least the trivial problems in the code (like unused
variables).
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Avoid warnings from -Wstrict-aliasing by using memcpy.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The code is trying to check that all the padding is zeroed out and it
does this:

    entry->padding[0] == entry->padding[1] == entry->padding[2] == 0

Assume everything is zeroed correctly, then the first comparison is
true, the next comparison is false and false is equal to zero so the
overall condition is true.  This bug doesn't affect run time very
badly, but the code should instead just check that all three paddings
are zero individually.

Also the error message was copy and pasted from an earlier error and it
wasn't correct.

Fixes: 7edcb734 ("KVM: selftests: Add hyperv_cpuid test")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

 WARNING: CPU: 0 PID: 13554 at kvm/arch/x86/kvm//../../../virt/kvm/kvm_main.c:4183 kvm_resume+0x3c/0x40 [kvm]
  CPU: 0 PID: 13554 Comm: step_after_susp Tainted: G           OE     5.1.0-rc4+ #1
  RIP: 0010:kvm_resume+0x3c/0x40 [kvm]
  Call Trace:
   syscore_resume+0x63/0x2d0
   suspend_devices_and_enter+0x9d1/0xa40
   pm_suspend+0x33a/0x3b0
   state_store+0x82/0xf0
   kobj_attr_store+0x12/0x20
   sysfs_kf_write+0x4b/0x60
   kernfs_fop_write+0x120/0x1a0
   __vfs_write+0x1b/0x40
   vfs_write+0xcd/0x1d0
   ksys_write+0x5f/0xe0
   __x64_sys_write+0x1a/0x20
   do_syscall_64+0x6f/0x6c0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit ca84d1a2 (KVM: x86: Add clock sync request to hardware enable) mentioned
that "we always hold kvm_lock when hardware_enable is called.  The one place that
doesn't need to worry about it is resume, as resuming a frozen CPU, the spinlock
won't be taken." However, commit 6706dae9 (virt/kvm: Replace spin_is_locked() with
lockdep) introduces a bug, it asserts when the lock is not held which is contrary
to the original goal.

This patch fixes it by WARN_ON when the lock is held.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Fixes: 6706dae9 ("virt/kvm: Replace spin_is_locked() with lockdep")
[Wrap with #ifdef CONFIG_LOCKDEP - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

VMX's nested_run_pending flag is subtly consumed when stuffing state to
enter guest mode, i.e. needs to be set according before KVM knows if
setting guest state is successful.  If setting guest state fails, clear
the flag as a nested run is obviously not pending.
Reported-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The offset for reading the shadow VMCS is sizeof(*kvm_state)+VMCS12_SIZE,
so the correct size must be that plus sizeof(*vmcs12).  This could lead
to KVM reading garbage data from userspace and not reporting an error,
but is otherwise not sensitive.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvmarm-fixes-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm updates for 5.2-rc2

- Correctly annotate HYP-callable code to be non-traceable
- Remove Christoffer from the MAINTAINERS file as his request

KVM has helpers to handle the condition codes of trapped aarch32
instructions. These are marked __hyp_text and used from HYP, but they
aren't built by the 'hyp' Makefile, which has all the runes to avoid ASAN
and KCOV instrumentation.

Move this code to a new hyp/aarch32.c to avoid a hyp-panic when starting
an aarch32 guest on a host built with the ASAN/KCOV debug options.

Fixes: 021234ef ("KVM: arm64: Make kvm_condition_valid32() accessible from EL2")
Fixes: 8cebe750 ("arm64: KVM: Make kvm_skip_instr32 available to HYP")
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

KVM's pmu.c contains the __hyp_text needed to switch the pmu registers
between host and guest. Because this isn't covered by the 'hyp' Makefile,
it can be built with kasan and friends when these are enabled in Kconfig.

When starting a guest, this results in:
| Kernel panic - not syncing: HYP panic:
| PS:a00003c9 PC:000083000028ada0 ESR:86000007
| FAR:000083000028ada0 HPFAR:0000000029df5300 PAR:0000000000000000
| VCPU:000000004e10b7d6
| CPU: 0 PID: 3088 Comm: qemu-system-aar Not tainted 5.2.0-rc1 #11026
| Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Plat
| Call trace:
|  dump_backtrace+0x0/0x200
|  show_stack+0x20/0x30
|  dump_stack+0xec/0x158
|  panic+0x1ec/0x420
|  panic+0x0/0x420
| SMP: stopping secondary CPUs
| Kernel Offset: disabled
| CPU features: 0x002,25006082
| Memory Limit: none
| ---[ end Kernel panic - not syncing: HYP panic:

This is caused by functions in pmu.c calling the instrumented
code, which isn't mapped to hyp. From objdump -r:
| RELOCATION RECORDS FOR [.hyp.text]:
| OFFSET           TYPE              VALUE
| 0000000000000010 R_AARCH64_CALL26  __sanitizer_cov_trace_pc
| 0000000000000018 R_AARCH64_CALL26  __asan_load4_noabort
| 0000000000000024 R_AARCH64_CALL26  __asan_load4_noabort

Move the affected code to a new file under 'hyp's Makefile.

Fixes: 3d91befb ("arm64: KVM: Enable !VHE support for :G/:H perf event modifiers")
Cc: Andrew Murray <Andrew.Murray@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

I no longer have time to actively review patches and manage the tree and
it's time to make that official.

Huge thanks to the incredible Linux community and all the contributors
who have put up with me over the past years.

I also take this opportunity to remove the website link to the Columbia
web page, as that information is no longer up to date and I don't know
who manages that anymore.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Merge tag 'kvm-s390-master-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Fixes for s390

- Fix typo in module parameter description
- Change default poll timer to improve cpu consumption

Recent measurements indicate that using 50us results in a reduced CPU
consumption, while still providing the benefit of halt polling. Let's
use 50us instead.
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Fix typo in parameter description.

Fixes: 8b905d28 ("KVM: s390: provide kvm_arch_no_poll function")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Message-Id: <20190504065145.53665-1-weiyongjun1@huawei.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Pull UBIFS fixes from Richard Weinberger:

 - build errors wrt xattrs

 - mismerge which lead to a wrong Kconfig ifdef

 - missing endianness conversion

* tag 'upstream-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs:
  ubifs: Convert xattr inum to host order
  ubifs: Use correct config name for encryption
  ubifs: Fix build error without CONFIG_UBIFS_FS_XATTR

Merge yet more updates from Andrew Morton:
 "A few final bits:

   - large changes to vmalloc, yielding large performance benefits

   - tweak the console-flush-on-panic code

   - a few fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  panic: add an option to replay all the printk message in buffer
  initramfs: don't free a non-existent initrd
  fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going into workqueue when umount
  mm/compaction.c: correct zone boundary handling when isolating pages from a pageblock
  mm/vmap: add DEBUG_AUGMENT_LOWEST_MATCH_CHECK macro
  mm/vmap: add DEBUG_AUGMENT_PROPAGATE_CHECK macro
  mm/vmalloc.c: keep track of free blocks for vmap allocation

Pull more Kbuild updates from Masahiro Yamada:

 - remove unneeded use of cc-option, cc-disable-warning, cc-ldoption

 - exclude tracked files from .gitignore

 - re-enable -Wint-in-bool-context warning

 - refactor samples/Makefile

 - stop building immediately if syncconfig fails

 - do not sprinkle error messages when $(CC) does not exist

 - move arch/alpha/defconfig to the configs subdirectory

 - remove crappy header search path manipulation

 - add comment lines to .config to clarify the end of menu blocks

 - check uniqueness of module names (adding new warnings intentionally)

* tag 'kbuild-v5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (24 commits)
  kconfig: use 'else ifneq' for Makefile to improve readability
  kbuild: check uniqueness of module names
  kconfig: Terminate menu blocks with a comment in the generated config
  kbuild: add LICENSES to KBUILD_ALLDIRS
  kbuild: remove 'addtree' and 'flags' magic for header search paths
  treewide: prefix header search paths with $(srctree)/
  media: prefix header search paths with $(srctree)/
  media: remove unneeded header search paths
  alpha: move arch/alpha/defconfig to arch/alpha/configs/defconfig
  kbuild: terminate Kconfig when $(CC) or $(LD) is missing
  kbuild: turn auto.conf.cmd into a mandatory include file
  .gitignore: exclude .get_maintainer.ignore and .gitattributes
  kbuild: add all Clang-specific flags unconditionally
  kbuild: Don't try to add '-fcatch-undefined-behavior' flag
  kbuild: add some extra warning flags unconditionally
  kbuild: add -Wvla flag unconditionally
  arch: remove dangling asm-generic wrappers
  samples: guard sub-directories with CONFIG options
  kbuild: re-enable int-in-bool-context warning
  MAINTAINERS: kbuild: Add pattern for scripts/*vmlinux*
  ...

Pull i2c updates from Wolfram Sang:
 "Some I2C core API additions which are kind of simple but enhance error
  checking for users a lot, especially by returning errno now.

  There are wrappers to still support the old API but it will be removed
  once all users are converted"

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: core: add device-managed version of i2c_new_dummy
  i2c: core: improve return value handling of i2c_new_device and i2c_new_dummy