linux/arch/arm64
Paolo Bonzini d495f942f4 KVM: fix bad user ABI for KVM_EXIT_SYSTEM_EVENT
When KVM_EXIT_SYSTEM_EVENT was introduced, it included a flags
member that at the time was unused.  Unfortunately this extensibility
mechanism has several issues:

- x86 is not writing the member, so it would not be possible to use it
  on x86 except for new events

- the member is not aligned to 64 bits, so the definition of the
  uAPI struct is incorrect for 32- on 64-bit userspace.  This is a
  problem for RISC-V, which supports CONFIG_KVM_COMPAT, but fortunately
  usage of flags was only introduced in 5.18.

Since padding has to be introduced, place a new field in there
that tells if the flags field is valid.  To allow further extensibility,
in fact, change flags to an array of 16 values, and store how many
of the values are valid.  The availability of the new ndata field
is tied to a system capability; all architectures are changed to
fill in the field.

To avoid breaking compilation of userspace that was using the flags
field, provide a userspace-only union to overlap flags with data[0].
The new field is placed at the same offset for both 32- and 64-bit
userspace.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Message-Id: <20220422103013.34832-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-29 12:38:22 -04:00
..
boot SoC: fixes for 5.18, part 1 2022-04-01 13:21:19 -07:00
configs ARM: DT updates for 5.18 2022-03-23 18:37:22 -07:00
crypto crypto: arm64 - cleanup comments 2022-03-09 15:12:32 +12:00
hyperv arm64: hyperv: Initialize hypervisor on boot 2021-08-04 16:54:36 +00:00
include KVM: arm64: mixed-width check should be skipped for uninitialized vCPUs 2022-04-06 12:29:45 +01:00
kernel ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
kvm KVM: fix bad user ABI for KVM_EXIT_SYSTEM_EVENT 2022-04-29 12:38:22 -04:00
lib Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2022-03-21 16:02:36 -07:00
mm kasan, arm64: don't tag executable vmalloc allocations 2022-03-24 19:06:48 -07:00
net kasan, arm64: don't tag executable vmalloc allocations 2022-03-24 19:06:48 -07:00
tools Merge branch 'for-next/spectre-bhb' into for-next/core 2022-03-14 19:08:31 +00:00
xen xen: allow pv-only hypercalls only with CONFIG_XEN_PV 2021-11-02 08:11:01 -05:00
Kbuild kbuild: use more subdir- for visiting subdirectories while cleaning 2021-10-24 13:49:46 +09:00
Kconfig Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
Kconfig.debug
Kconfig.platforms ARM: DT updates for 5.18 2022-03-23 18:37:22 -07:00
Makefile arm64/xor: use EOR3 instructions when available 2021-12-14 12:14:26 +00:00