linux.git/arch/s390, branch v6.9

Merge tag 'for-linus-6.9' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2024-05-12T19:15:39+00:00

Pull kvm fix from Paolo Bonzini:

 - Fix NULL pointer read on s390 in ioctl(KVM_CHECK_EXTENSION) for
   /dev/kvm

* tag 'for-linus-6.9' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: s390: Check kvm pointer when testing KVM_CAP_S390_HPAGE_1M

KVM: s390: Check kvm pointer when testing KVM_CAP_S390_HPAGE_1M

2024-05-02T07:41:38+00:00

KVM allows issuing the KVM_CHECK_EXTENSION ioctl either on the /dev/kvm
fd or the VM fd. In the first case, kvm_vm_ioctl_check_extension() is
called with kvm==NULL. Ensure we don't dereference the pointer in that
case.

Fixes: 40ebdb8e59df ("KVM: s390: Make huge pages unavailable in ucontrol VMs")
Signed-off-by: Jean-Philippe Brucker 
Reviewed-by: Claudio Imbrenda 
Reviewed-by: Christian Borntraeger 
Message-ID: <20240419160723.320910-2-jean-philippe@linaro.org>
Signed-off-by: Christian Borntraeger

s390/paes: Reestablish retry loop in paes

2024-05-01T09:52:54+00:00

With commit ed6776c96c60 ("s390/crypto: remove retry
loop with sleep from PAES pkey invocation") the retry
loop to retry derivation of a protected key from a
secure key has been removed. This was based on the
assumption that theses retries are not needed any
more as proper retries are done in the zcrypt layer.

However, tests have revealed that there exist some
cases with master key change in the HSM and immediately
(< 1 second) attempt to derive a protected key from a
secure key with exact this HSM may eventually fail.

The low level functions in zcrypt_ccamisc.c and
zcrypt_ep11misc.c detect and report this temporary
failure and report it to the caller as -EBUSY. The
re-established retry loop in the paes implementation
catches exactly this -EBUSY and eventually may run
some retries.

Fixes: ed6776c96c60 ("s390/crypto: remove retry loop with sleep from PAES pkey invocation")
Signed-off-by: Harald Freudenberger 
Reviewed-by: Ingo Franzki 
Reviewed-by: Holger Dengler 
Signed-off-by: Alexander Gordeev

s390/vdso: Add CFI for RA register to asm macro vdso_func

2024-04-26T14:22:38+00:00

The return-address (RA) register r14 is specified as volatile in the
s390x ELF ABI [1]. Nevertheless proper CFI directives must be provided
for an unwinder to restore the return address, if the RA register
value is changed from its value at function entry, as it is the case.

[1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases

Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Signed-off-by: Jens Remus 
Acked-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/mm: Fix clearing storage keys for huge pages

2024-04-22T10:47:47+00:00

The function __storage_key_init_range() expects the end address to be
the first byte outside the range to be initialized. I.e. end - start
should be the size of the area to be initialized.

The current code works because __storage_key_init_range() will still loop
over every page in the range, but it is slower than using sske_frame().

Fixes: 3afdfca69870 ("s390/mm: Clear skeys for newly mapped huge guest pmds")
Reviewed-by: Heiko Carstens 
Signed-off-by: Claudio Imbrenda 
Link: https://lore.kernel.org/r/20240416114220.28489-3-imbrenda@linux.ibm.com
Signed-off-by: Alexander Gordeev

s390/mm: Fix storage key clearing for guest huge pages

2024-04-22T10:47:47+00:00

The function __storage_key_init_range() expects the end address to be
the first byte outside the range to be initialized. I.e. end - start
should be the size of the area to be initialized.

The current code works because __storage_key_init_range() will still loop
over every page in the range, but it is slower than using sske_frame().

Fixes: 964c2c05c9f3 ("s390/mm: Clear huge page storage keys on enable_skey")
Reviewed-by: Heiko Carstens 
Signed-off-by: Claudio Imbrenda 
Link: https://lore.kernel.org/r/20240416114220.28489-2-imbrenda@linux.ibm.com
Signed-off-by: Alexander Gordeev

s390/mm: Fix NULL pointer dereference

2024-04-17T15:26:34+00:00

The recently added check to figure out if a fault happened on gmap ASCE
dereferences the gmap pointer in lowcore without checking that it is not
NULL. For all non-KVM processes the pointer is NULL, so that some value
from lowcore will be read. With the current layouts of struct gmap and
struct lowcore the read value (aka ASCE) is zero, so that this doesn't lead
to any observable bug; at least currently.

Fix this by adding the missing NULL pointer check.

Fixes: 64c3431808bd ("s390/entry: compare gmap asce to determine guest/host fault")
Signed-off-by: Sven Schnelle 
Reviewed-by: Claudio Imbrenda 
Reviewed-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/entry: align system call table on 8 bytes

2024-04-03T13:00:20+00:00

Align system call table on 8 bytes. With sys_call_table entry size
of 8 bytes that eliminates the possibility of a system call pointer
crossing cache line boundary.

Cc: stable@kernel.org
Suggested-by: Ulrich Weigand 
Reviewed-by: Alexander Gordeev 
Signed-off-by: Sumanth Korikkar 
Signed-off-by: Vasily Gorbik

s390/pai: fix sampling event removal for PMU device driver

2024-04-03T13:00:20+00:00

In case of a sampling event, the PAI PMU device drivers need a
reference to this event.  Currently to PMU device driver reference
is removed when a sampling event is destroyed. This may lead to
situations where the reference of the PMU device driver is removed
while being used by a different sampling event.
Reset the event reference pointer of the PMU device driver when
a sampling event is deleted and before the next one might be added.

Fixes: 39d62336f5c1 ("s390/pai: add support for cryptography counters")
Signed-off-by: Thomas Richter 
Acked-by: Sumanth Korikkar 
Signed-off-by: Vasily Gorbik

s390/preempt: mark all functions __always_inline

2024-04-03T13:00:20+00:00

preempt_count-related functions are quite ubiquitous and may be called
by noinstr ones, introducing unwanted instrumentation. Here is one
example call chain:

  irqentry_nmi_enter()  # noinstr
    lockdep_hardirqs_enabled()
      this_cpu_read()
        __pcpu_size_call_return()
          this_cpu_read_*()
            this_cpu_generic_read()
              __this_cpu_generic_read_nopreempt()
                preempt_disable_notrace()
                  __preempt_count_inc()
                    __preempt_count_add()

They are very small, so there are no significant downsides to
force-inlining them.

Signed-off-by: Ilya Leoshkevich 
Link: https://lore.kernel.org/r/20240320230007.4782-3-iii@linux.ibm.com
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik