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Author SHA1 Message Date
Linus Torvalds
0ff0edb550 Locking changes for this cycle were:
- rtmutex cleanup & spring cleaning pass that removes ~400 lines of code
  - Futex simplifications & cleanups
  - Add debugging to the CSD code, to help track down a tenacious race (or hw problem)
  - Add lockdep_assert_not_held(), to allow code to require a lock to not be held,
    and propagate this into the ath10k driver
  - Misc LKMM documentation updates
  - Misc KCSAN updates: cleanups & documentation updates
  - Misc fixes and cleanups
  - Fix locktorture bugs with ww_mutexes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:

 - rtmutex cleanup & spring cleaning pass that removes ~400 lines of
   code

 - Futex simplifications & cleanups

 - Add debugging to the CSD code, to help track down a tenacious race
   (or hw problem)

 - Add lockdep_assert_not_held(), to allow code to require a lock to not
   be held, and propagate this into the ath10k driver

 - Misc LKMM documentation updates

 - Misc KCSAN updates: cleanups & documentation updates

 - Misc fixes and cleanups

 - Fix locktorture bugs with ww_mutexes

* tag 'locking-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  kcsan: Fix printk format string
  static_call: Relax static_call_update() function argument type
  static_call: Fix unused variable warn w/o MODULE
  locking/rtmutex: Clean up signal handling in __rt_mutex_slowlock()
  locking/rtmutex: Restrict the trylock WARN_ON() to debug
  locking/rtmutex: Fix misleading comment in rt_mutex_postunlock()
  locking/rtmutex: Consolidate the fast/slowpath invocation
  locking/rtmutex: Make text section and inlining consistent
  locking/rtmutex: Move debug functions as inlines into common header
  locking/rtmutex: Decrapify __rt_mutex_init()
  locking/rtmutex: Remove pointless CONFIG_RT_MUTEXES=n stubs
  locking/rtmutex: Inline chainwalk depth check
  locking/rtmutex: Move rt_mutex_debug_task_free() to rtmutex.c
  locking/rtmutex: Remove empty and unused debug stubs
  locking/rtmutex: Consolidate rt_mutex_init()
  locking/rtmutex: Remove output from deadlock detector
  locking/rtmutex: Remove rtmutex deadlock tester leftovers
  locking/rtmutex: Remove rt_mutex_timed_lock()
  MAINTAINERS: Add myself as futex reviewer
  locking/mutex: Remove repeated declaration
  ...
2021-04-28 12:37:53 -07:00
Linus Torvalds
c6536676c7 - turn the stack canary into a normal __percpu variable on 32-bit which
gets rid of the LAZY_GS stuff and a lot of code.
 
 - Add an insn_decode() API which all users of the instruction decoder
 should preferrably use. Its goal is to keep the details of the
 instruction decoder away from its users and simplify and streamline how
 one decodes insns in the kernel. Convert its users to it.
 
 - kprobes improvements and fixes
 
 - Set the maximum DIE per package variable on Hygon
 
 - Rip out the dynamic NOP selection and simplify all the machinery around
 selecting NOPs. Use the simplified NOPs in objtool now too.
 
 - Add Xeon Sapphire Rapids to list of CPUs that support PPIN
 
 - Simplify the retpolines by folding the entire thing into an
 alternative now that objtool can handle alternatives with stack
 ops. Then, have objtool rewrite the call to the retpoline with the
 alternative which then will get patched at boot time.
 
 - Document Intel uarch per models in intel-family.h
 
 - Make Sub-NUMA Clustering topology the default and Cluster-on-Die the
 exception on Intel.
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Merge tag 'x86_core_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 updates from Borislav Petkov:

 - Turn the stack canary into a normal __percpu variable on 32-bit which
   gets rid of the LAZY_GS stuff and a lot of code.

 - Add an insn_decode() API which all users of the instruction decoder
   should preferrably use. Its goal is to keep the details of the
   instruction decoder away from its users and simplify and streamline
   how one decodes insns in the kernel. Convert its users to it.

 - kprobes improvements and fixes

 - Set the maximum DIE per package variable on Hygon

 - Rip out the dynamic NOP selection and simplify all the machinery
   around selecting NOPs. Use the simplified NOPs in objtool now too.

 - Add Xeon Sapphire Rapids to list of CPUs that support PPIN

 - Simplify the retpolines by folding the entire thing into an
   alternative now that objtool can handle alternatives with stack ops.
   Then, have objtool rewrite the call to the retpoline with the
   alternative which then will get patched at boot time.

 - Document Intel uarch per models in intel-family.h

 - Make Sub-NUMA Clustering topology the default and Cluster-on-Die the
   exception on Intel.

* tag 'x86_core_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
  x86, sched: Treat Intel SNC topology as default, COD as exception
  x86/cpu: Comment Skylake server stepping too
  x86/cpu: Resort and comment Intel models
  objtool/x86: Rewrite retpoline thunk calls
  objtool: Skip magical retpoline .altinstr_replacement
  objtool: Cache instruction relocs
  objtool: Keep track of retpoline call sites
  objtool: Add elf_create_undef_symbol()
  objtool: Extract elf_symbol_add()
  objtool: Extract elf_strtab_concat()
  objtool: Create reloc sections implicitly
  objtool: Add elf_create_reloc() helper
  objtool: Rework the elf_rebuild_reloc_section() logic
  objtool: Fix static_call list generation
  objtool: Handle per arch retpoline naming
  objtool: Correctly handle retpoline thunk calls
  x86/retpoline: Simplify retpolines
  x86/alternatives: Optimize optimize_nops()
  x86: Add insn_decode_kernel()
  x86/kprobes: Move 'inline' to the beginning of the kprobe_is_ss() declaration
  ...
2021-04-27 17:45:09 -07:00
Linus Torvalds
4d480dbf21 hyperv-next for 5.13
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Merge tag 'hyperv-next-signed-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V updates from Wei Liu:

 - VMBus enhancement

 - Free page reporting support for Hyper-V balloon driver

 - Some patches for running Linux as Arm64 Hyper-V guest

 - A few misc clean-up patches

* tag 'hyperv-next-signed-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (30 commits)
  drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status
  x86/hyperv: Move hv_do_rep_hypercall to asm-generic
  video: hyperv_fb: Add ratelimit on error message
  Drivers: hv: vmbus: Increase wait time for VMbus unload
  Drivers: hv: vmbus: Initialize unload_event statically
  Drivers: hv: vmbus: Check for pending channel interrupts before taking a CPU offline
  Drivers: hv: vmbus: Drivers: hv: vmbus: Introduce CHANNELMSG_MODIFYCHANNEL_RESPONSE
  Drivers: hv: vmbus: Introduce and negotiate VMBus protocol version 5.3
  Drivers: hv: vmbus: Use after free in __vmbus_open()
  Drivers: hv: vmbus: remove unused function
  Drivers: hv: vmbus: Remove unused linux/version.h header
  x86/hyperv: remove unused linux/version.h header
  x86/Hyper-V: Support for free page reporting
  x86/hyperv: Fix unused variable 'hi' warning in hv_apic_read
  x86/hyperv: Fix unused variable 'msr_val' warning in hv_qlock_wait
  hv: hyperv.h: a few mundane typo fixes
  drivers: hv: Fix EXPORT_SYMBOL and tab spaces issue
  Drivers: hv: vmbus: Drop error message when 'No request id available'
  asm-generic/hyperv: Add missing function prototypes per -W1 warnings
  clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts
  ...
2021-04-26 10:44:16 -07:00
Linus Torvalds
64f8e73de0 Support for enhanced split lock detection:
Newer CPUs provide a second mechanism to detect operations with lock
   prefix which go accross a cache line boundary. Such operations have to
   take bus lock which causes a system wide performance degradation when
   these operations happen frequently.
 
   The new mechanism is not using the #AC exception. It triggers #DB and is
   restricted to operations in user space. Kernel side split lock access can
   only be detected by the #AC based variant. Contrary to the #AC based
   mechanism the #DB based variant triggers _after_ the instruction was
   executed. The mechanism is CPUID enumerated and contrary to the #AC
   version which is based on the magic TEST_CTRL_MSR and model/family based
   enumeration on the way to become architectural.
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Merge tag 'x86-splitlock-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 bus lock detection updates from Thomas Gleixner:
 "Support for enhanced split lock detection:

  Newer CPUs provide a second mechanism to detect operations with lock
  prefix which go accross a cache line boundary. Such operations have to
  take bus lock which causes a system wide performance degradation when
  these operations happen frequently.

  The new mechanism is not using the #AC exception. It triggers #DB and
  is restricted to operations in user space. Kernel side split lock
  access can only be detected by the #AC based variant.

  Contrary to the #AC based mechanism the #DB based variant triggers
  _after_ the instruction was executed. The mechanism is CPUID
  enumerated and contrary to the #AC version which is based on the magic
  TEST_CTRL_MSR and model/family based enumeration on the way to become
  architectural"

* tag 'x86-splitlock-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/admin-guide: Change doc for split_lock_detect parameter
  x86/traps: Handle #DB for bus lock
  x86/cpufeatures: Enumerate #DB for bus lock detection
2021-04-26 10:09:38 -07:00
Linus Torvalds
eea2647e74 Entry code update:
Provide support for randomized stack offsets per syscall to make
  stack-based attacks harder which rely on the deterministic stack layout.
 
  The feature is based on the original idea of PaX's RANDSTACK feature, but
  uses a significantly different implementation.
 
  The offset does not affect the pt_regs location on the task stack as this
  was agreed on to be of dubious value. The offset is applied before the
  actual syscall is invoked.
 
  The offset is stored per cpu and the randomization happens at the end of
  the syscall which is less predictable than on syscall entry.
 
  The mechanism to apply the offset is via alloca(), i.e. abusing the
  dispised VLAs. This comes with the drawback that stack-clash-protection
  has to be disabled for the affected compilation units and there is also
  a negative interaction with stack-protector.
 
  Those downsides are traded with the advantage that this approach does not
  require any intrusive changes to the low level assembly entry code, does
  not affect the unwinder and the correct stack alignment is handled
  automatically by the compiler.
 
  The feature is guarded with a static branch which avoids the overhead when
  disabled.
 
  Currently this is supported for X86 and ARM64.
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Merge tag 'x86-entry-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull entry code update from Thomas Gleixner:
 "Provide support for randomized stack offsets per syscall to make
  stack-based attacks harder which rely on the deterministic stack
  layout.

  The feature is based on the original idea of PaX's RANDSTACK feature,
  but uses a significantly different implementation.

  The offset does not affect the pt_regs location on the task stack as
  this was agreed on to be of dubious value. The offset is applied
  before the actual syscall is invoked.

  The offset is stored per cpu and the randomization happens at the end
  of the syscall which is less predictable than on syscall entry.

  The mechanism to apply the offset is via alloca(), i.e. abusing the
  dispised VLAs. This comes with the drawback that
  stack-clash-protection has to be disabled for the affected compilation
  units and there is also a negative interaction with stack-protector.

  Those downsides are traded with the advantage that this approach does
  not require any intrusive changes to the low level assembly entry
  code, does not affect the unwinder and the correct stack alignment is
  handled automatically by the compiler.

  The feature is guarded with a static branch which avoids the overhead
  when disabled.

  Currently this is supported for X86 and ARM64"

* tag 'x86-entry-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64: entry: Enable random_kstack_offset support
  lkdtm: Add REPORT_STACK for checking stack offsets
  x86/entry: Enable random_kstack_offset support
  stack: Optionally randomize kernel stack offset each syscall
  init_on_alloc: Optimize static branches
  jump_label: Provide CONFIG-driven build state defaults
2021-04-26 10:02:09 -07:00
Linus Torvalds
ea5bc7b977 Trivial cleanups and fixes all over the place.
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Merge tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 cleanups from Borislav Petkov:
 "Trivial cleanups and fixes all over the place"

* tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Remove me from IDE/ATAPI section
  x86/pat: Do not compile stubbed functions when X86_PAT is off
  x86/asm: Ensure asm/proto.h can be included stand-alone
  x86/platform/intel/quark: Fix incorrect kernel-doc comment syntax in files
  x86/msr: Make locally used functions static
  x86/cacheinfo: Remove unneeded dead-store initialization
  x86/process/64: Move cpu_current_top_of_stack out of TSS
  tools/turbostat: Unmark non-kernel-doc comment
  x86/syscalls: Fix -Wmissing-prototypes warnings from COND_SYSCALL()
  x86/fpu/math-emu: Fix function cast warning
  x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes
  x86: Fix various typos in comments, take #2
  x86: Remove unusual Unicode characters from comments
  x86/kaslr: Return boolean values from a function returning bool
  x86: Fix various typos in comments
  x86/setup: Remove unused RESERVE_BRK_ARRAY()
  stacktrace: Move documentation for arch_stack_walk_reliable() to header
  x86: Remove duplicate TSC DEADLINE MSR definitions
2021-04-26 09:25:47 -07:00
Linus Torvalds
81a489790a Add the guest side of SGX support in KVM guests. Work by Sean
Christopherson, Kai Huang and Jarkko Sakkinen. Along with the usual
 fixes, cleanups and improvements.
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Merge tag 'x86_sgx_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SGX updates from Borislav Petkov:
 "Add the guest side of SGX support in KVM guests. Work by Sean
  Christopherson, Kai Huang and Jarkko Sakkinen.

  Along with the usual fixes, cleanups and improvements"

* tag 'x86_sgx_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/sgx: Mark sgx_vepc_vm_ops static
  x86/sgx: Do not update sgx_nr_free_pages in sgx_setup_epc_section()
  x86/sgx: Move provisioning device creation out of SGX driver
  x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs
  x86/sgx: Add encls_faulted() helper
  x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT)
  x86/sgx: Move ENCLS leaf definitions to sgx.h
  x86/sgx: Expose SGX architectural definitions to the kernel
  x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled
  x86/cpu/intel: Allow SGX virtualization without Launch Control support
  x86/sgx: Introduce virtual EPC for use by KVM guests
  x86/sgx: Add SGX_CHILD_PRESENT hardware error code
  x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
  x86/cpufeatures: Add SGX1 and SGX2 sub-features
  x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit
  x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init()
  selftests/sgx: Use getauxval() to simplify test code
  selftests/sgx: Improve error detection and messages
  x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()
  ...
2021-04-26 09:15:56 -07:00
Linus Torvalds
2c5ce2dba2 First big cleanup to the paravirt infra to use alternatives and thus
eliminate custom code patching. For that, the alternatives infra is
 extended to accomodate paravirt's needs and, as a result, a lot of
 paravirt patching code goes away, leading to a sizeable cleanup and
 simplification. Work by Juergen Gross.
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Merge tag 'x86_alternatives_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 alternatives/paravirt updates from Borislav Petkov:
 "First big cleanup to the paravirt infra to use alternatives and thus
  eliminate custom code patching.

  For that, the alternatives infrastructure is extended to accomodate
  paravirt's needs and, as a result, a lot of paravirt patching code
  goes away, leading to a sizeable cleanup and simplification.

  Work by Juergen Gross"

* tag 'x86_alternatives_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/paravirt: Have only one paravirt patch function
  x86/paravirt: Switch functions with custom code to ALTERNATIVE
  x86/paravirt: Add new PVOP_ALT* macros to support pvops in ALTERNATIVEs
  x86/paravirt: Switch iret pvops to ALTERNATIVE
  x86/paravirt: Simplify paravirt macros
  x86/paravirt: Remove no longer needed 32-bit pvops cruft
  x86/paravirt: Add new features for paravirt patching
  x86/alternative: Use ALTERNATIVE_TERNARY() in _static_cpu_has()
  x86/alternative: Support ALTERNATIVE_TERNARY
  x86/alternative: Support not-feature
  x86/paravirt: Switch time pvops functions to use static_call()
  static_call: Add function to query current function
  static_call: Move struct static_call_key definition to static_call_types.h
  x86/alternative: Merge include files
  x86/alternative: Drop unused feature parameter from ALTINSTR_REPLACEMENT()
2021-04-26 09:01:29 -07:00
Sean Christopherson
4daf2a1c45 x86/sev: Drop redundant and potentially misleading 'sev_enabled'
Drop the sev_enabled flag and switch its one user over to sev_active().
sev_enabled was made redundant with the introduction of sev_status in
commit b57de6cd16 ("x86/sev-es: Add SEV-ES Feature Detection").
sev_enabled and sev_active() are guaranteed to be equivalent, as each is
true iff 'sev_status & MSR_AMD64_SEV_ENABLED' is true, and are only ever
written in tandem (ignoring compressed boot's version of sev_status).

Removing sev_enabled avoids confusion over whether it refers to the guest
or the host, and will also allow KVM to usurp "sev_enabled" for its own
purposes.

No functional change intended.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422021125.3417167-7-seanjc@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-26 05:27:14 -04:00
Paolo Bonzini
fd49e8ee70 Merge branch 'kvm-sev-cgroup' into HEAD 2021-04-22 13:19:01 -04:00
Nathan Tempelman
54526d1fd5 KVM: x86: Support KVM VMs sharing SEV context
Add a capability for userspace to mirror SEV encryption context from
one vm to another. On our side, this is intended to support a
Migration Helper vCPU, but it can also be used generically to support
other in-guest workloads scheduled by the host. The intention is for
the primary guest and the mirror to have nearly identical memslots.

The primary benefits of this are that:
1) The VMs do not share KVM contexts (think APIC/MSRs/etc), so they
can't accidentally clobber each other.
2) The VMs can have different memory-views, which is necessary for post-copy
migration (the migration vCPUs on the target need to read and write to
pages, when the primary guest would VMEXIT).

This does not change the threat model for AMD SEV. Any memory involved
is still owned by the primary guest and its initial state is still
attested to through the normal SEV_LAUNCH_* flows. If userspace wanted
to circumvent SEV, they could achieve the same effect by simply attaching
a vCPU to the primary VM.
This patch deliberately leaves userspace in charge of the memslots for the
mirror, as it already has the power to mess with them in the primary guest.

This patch does not support SEV-ES (much less SNP), as it does not
handle handing off attested VMSAs to the mirror.

For additional context, we need a Migration Helper because SEV PSP
migration is far too slow for our live migration on its own. Using
an in-guest migrator lets us speed this up significantly.

Signed-off-by: Nathan Tempelman <natet@google.com>
Message-Id: <20210408223214.2582277-1-natet@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-21 12:20:02 -04:00
Joseph Salisbury
753ed9c95c drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status
There is not a consistent pattern for checking Hyper-V hypercall status.
Existing code uses a number of variants.  The variants work, but a consistent
pattern would improve the readability of the code, and be more conformant
to what the Hyper-V TLFS says about hypercall status.

Implemented new helper functions hv_result(), hv_result_success(), and
hv_repcomp().  Changed the places where hv_do_hypercall() and related variants
are used to use the helper functions.

Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1618620183-9967-2-git-send-email-joseph.salisbury@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-21 09:49:19 +00:00
Joseph Salisbury
6523592cee x86/hyperv: Move hv_do_rep_hypercall to asm-generic
This patch makes no functional changes.  It simply moves hv_do_rep_hypercall()
out of arch/x86/include/asm/mshyperv.h and into asm-generic/mshyperv.h

hv_do_rep_hypercall() is architecture independent, so it makes sense that it
should be in the architecture independent mshyperv.h, not in the x86-specific
mshyperv.h.

This is done in preperation for a follow up patch which creates a consistent
pattern for checking Hyper-V hypercall status.

Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1618620183-9967-1-git-send-email-joseph.salisbury@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-21 09:49:19 +00:00
Colin Ian King
b53002e035 floppy: remove redundant assignment to variable st
The variable st is being assigned a value that is never read and
it is being updated later with a new value. The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Denis Efremov <efremov@linux.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210415130020.1959951-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-04-20 08:59:03 -06:00
Sean Christopherson
70210c044b KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions
Add an ECREATE handler that will be used to intercept ECREATE for the
purpose of enforcing and enclave's MISCSELECT, ATTRIBUTES and XFRM, i.e.
to allow userspace to restrict SGX features via CPUID.  ECREATE will be
intercepted when any of the aforementioned masks diverges from hardware
in order to enforce the desired CPUID model, i.e. inject #GP if the
guest attempts to set a bit that hasn't been enumerated as allowed-1 in
CPUID.

Note, access to the PROVISIONKEY is not yet supported.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <c3a97684f1b71b4f4626a1fc3879472a95651725.1618196135.git.kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:55 -04:00
Sean Christopherson
3c0c2ad1ae KVM: VMX: Add basic handling of VM-Exit from SGX enclave
Add support for handling VM-Exits that originate from a guest SGX
enclave.  In SGX, an "enclave" is a new CPL3-only execution environment,
wherein the CPU and memory state is protected by hardware to make the
state inaccesible to code running outside of the enclave.  When exiting
an enclave due to an asynchronous event (from the perspective of the
enclave), e.g. exceptions, interrupts, and VM-Exits, the enclave's state
is automatically saved and scrubbed (the CPU loads synthetic state), and
then reloaded when re-entering the enclave.  E.g. after an instruction
based VM-Exit from an enclave, vmcs.GUEST_RIP will not contain the RIP
of the enclave instruction that trigered VM-Exit, but will instead point
to a RIP in the enclave's untrusted runtime (the guest userspace code
that coordinates entry/exit to/from the enclave).

To help a VMM recognize and handle exits from enclaves, SGX adds bits to
existing VMCS fields, VM_EXIT_REASON.VMX_EXIT_REASON_FROM_ENCLAVE and
GUEST_INTERRUPTIBILITY_INFO.GUEST_INTR_STATE_ENCLAVE_INTR.  Define the
new architectural bits, and add a boolean to struct vcpu_vmx to cache
VMX_EXIT_REASON_FROM_ENCLAVE.  Clear the bit in exit_reason so that
checks against exit_reason do not need to account for SGX, e.g.
"if (exit_reason == EXIT_REASON_EXCEPTION_NMI)" continues to work.

KVM is a largely a passive observer of the new bits, e.g. KVM needs to
account for the bits when propagating information to a nested VMM, but
otherwise doesn't need to act differently for the majority of VM-Exits
from enclaves.

The one scenario that is directly impacted is emulation, which is for
all intents and purposes impossible[1] since KVM does not have access to
the RIP or instruction stream that triggered the VM-Exit.  The inability
to emulate is a non-issue for KVM, as most instructions that might
trigger VM-Exit unconditionally #UD in an enclave (before the VM-Exit
check.  For the few instruction that conditionally #UD, KVM either never
sets the exiting control, e.g. PAUSE_EXITING[2], or sets it if and only
if the feature is not exposed to the guest in order to inject a #UD,
e.g. RDRAND_EXITING.

But, because it is still possible for a guest to trigger emulation,
e.g. MMIO, inject a #UD if KVM ever attempts emulation after a VM-Exit
from an enclave.  This is architecturally accurate for instruction
VM-Exits, and for MMIO it's the least bad choice, e.g. it's preferable
to killing the VM.  In practice, only broken or particularly stupid
guests should ever encounter this behavior.

Add a WARN in skip_emulated_instruction to detect any attempt to
modify the guest's RIP during an SGX enclave VM-Exit as all such flows
should either be unreachable or must handle exits from enclaves before
getting to skip_emulated_instruction.

[1] Impossible for all practical purposes.  Not truly impossible
    since KVM could implement some form of para-virtualization scheme.

[2] PAUSE_LOOP_EXITING only affects CPL0 and enclaves exist only at
    CPL3, so we also don't need to worry about that interaction.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <315f54a8507d09c292463ef29104e1d4c62e9090.1618196135.git.kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:54 -04:00
Sean Christopherson
00e7646c35 KVM: x86: Define new #PF SGX error code bit
Page faults that are signaled by the SGX Enclave Page Cache Map (EPCM),
as opposed to the traditional IA32/EPT page tables, set an SGX bit in
the error code to indicate that the #PF was induced by SGX.  KVM will
need to emulate this behavior as part of its trap-and-execute scheme for
virtualizing SGX Launch Control, e.g. to inject SGX-induced #PFs if
EINIT faults in the host, and to support live migration.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <e170c5175cb9f35f53218a7512c9e3db972b97a2.1618196135.git.kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:54 -04:00
Keqian Zhu
d90b15edbe KVM: x86: Remove unused function declaration
kvm_mmu_slot_largepage_remove_write_access() is decared but not used,
just remove it.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Message-Id: <20210406063504.17552-1-zhukeqian1@huawei.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:50 -04:00
Wanpeng Li
4a7132efff KVM: X86: Count attempted/successful directed yield
To analyze some performance issues with lock contention and scheduling,
it is nice to know when directed yield are successful or failing.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1617941911-5338-2-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-19 18:04:46 -04:00
Kan Liang
d0946a882e perf/x86/intel: Hybrid PMU support for perf capabilities
Some platforms, e.g. Alder Lake, have hybrid architecture. Although most
PMU capabilities are the same, there are still some unique PMU
capabilities for different hybrid PMUs. Perf should register a dedicated
pmu for each hybrid PMU.

Add a new struct x86_hybrid_pmu, which saves the dedicated pmu and
capabilities for each hybrid PMU.

The architecture MSR, MSR_IA32_PERF_CAPABILITIES, only indicates the
architecture features which are available on all hybrid PMUs. The
architecture features are stored in the global x86_pmu.intel_cap.

For Alder Lake, the model-specific features are perf metrics and
PEBS-via-PT. The corresponding bits of the global x86_pmu.intel_cap
should be 0 for these two features. Perf should not use the global
intel_cap to check the features on a hybrid system.
Add a dedicated intel_cap in the x86_hybrid_pmu to store the
model-specific capabilities. Use the dedicated intel_cap to replace
the global intel_cap for thse two features. The dedicated intel_cap
will be set in the following "Add Alder Lake Hybrid support" patch.

Add is_hybrid() to distinguish a hybrid system. ADL may have an
alternative configuration. With that configuration, the
X86_FEATURE_HYBRID_CPU is not set. Perf cannot rely on the feature bit.
Add a new static_key_false, perf_is_hybrid, to indicate a hybrid system.
It will be assigned in the following "Add Alder Lake Hybrid support"
patch as well.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1618237865-33448-5-git-send-email-kan.liang@linux.intel.com
2021-04-19 20:03:24 +02:00
Ricardo Neri
250b3c0d79 x86/cpu: Add helper function to get the type of the current hybrid CPU
On processors with Intel Hybrid Technology (i.e., one having more than
one type of CPU in the same package), all CPUs support the same
instruction set and enumerate the same features on CPUID. Thus, all
software can run on any CPU without restrictions. However, there may be
model-specific differences among types of CPUs. For instance, each type
of CPU may support a different number of performance counters. Also,
machine check error banks may be wired differently. Even though most
software will not care about these differences, kernel subsystems
dealing with these differences must know.

Add and expose a new helper function get_this_hybrid_cpu_type() to query
the type of the current hybrid CPU. The function will be used later in
the perf subsystem.

The Intel Software Developer's Manual defines the CPU type as 8-bit
identifier.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1618237865-33448-3-git-send-email-kan.liang@linux.intel.com
2021-04-19 20:03:23 +02:00
Ricardo Neri
a161545ab5 x86/cpufeatures: Enumerate Intel Hybrid Technology feature bit
Add feature enumeration to identify a processor with Intel Hybrid
Technology: one in which CPUs of more than one type are the same package.
On a hybrid processor, all CPUs support the same homogeneous (i.e.,
symmetric) instruction set. All CPUs enumerate the same features in CPUID.
Thus, software (user space and kernel) can run and migrate to any CPU in
the system as well as utilize any of the enumerated features without any
change or special provisions. The main difference among CPUs in a hybrid
processor are power and performance properties.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1618237865-33448-2-git-send-email-kan.liang@linux.intel.com
2021-04-19 20:03:23 +02:00
Ben Gardon
c0e64238ac KVM: x86/mmu: Protect the tdp_mmu_roots list with RCU
Protect the contents of the TDP MMU roots list with RCU in preparation
for a future patch which will allow the iterator macro to be used under
the MMU lock in read mode.

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210401233736.638171-9-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-19 09:06:01 -04:00
Sean Christopherson
b4c5936c47 KVM: Kill off the old hva-based MMU notifier callbacks
Yank out the hva-based MMU notifier APIs now that all architectures that
use the notifiers have moved to the gfn-based APIs.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210402005658.3024832-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17 08:31:08 -04:00
Sean Christopherson
3039bcc744 KVM: Move x86's MMU notifier memslot walkers to generic code
Move the hva->gfn lookup for MMU notifiers into common code.  Every arch
does a similar lookup, and some arch code is all but identical across
multiple architectures.

In addition to consolidating code, this will allow introducing
optimizations that will benefit all architectures without incurring
multiple walks of the memslots, e.g. by taking mmu_lock if and only if a
relevant range exists in the memslots.

The use of __always_inline to avoid indirect call retpolines, as done by
x86, may also benefit other architectures.

Consolidating the lookups also fixes a wart in x86, where the legacy MMU
and TDP MMU each do their own memslot walks.

Lastly, future enhancements to the memslot implementation, e.g. to add an
interval tree to track host address, will need to touch far less arch
specific code.

MIPS, PPC, and arm64 will be converted one at a time in future patches.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210402005658.3024832-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17 08:31:06 -04:00
Maxim Levitsky
7e582ccbbd KVM: x86: implement KVM_CAP_SET_GUEST_DEBUG2
Store the supported bits into KVM_GUESTDBG_VALID_MASK
macro, similar to how arm does this.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210401135451.1004564-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17 08:31:02 -04:00
Sean Christopherson
5f7c292b89 KVM: Move prototypes for MMU notifier callbacks to generic code
Move the prototypes for the MMU notifier callbacks out of arch code and
into common code.  There is no benefit to having each arch replicate the
prototypes since any deviation from the invocation in common code will
explode.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210326021957.1424875-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17 08:30:55 -04:00
Paolo Bonzini
d9bd0082e2 Merge remote-tracking branch 'tip/x86/sgx' into kvm-next
Pull generic x86 SGX changes needed to support SGX in virtual machines.
2021-04-17 08:29:47 -04:00
Christophe Leroy
808094fcbf lib/vdso: Add vdso_data pointer as input to __arch_get_timens_vdso_data()
For the same reason as commit e876f0b69d ("lib/vdso: Allow
architectures to provide the vdso data pointer"), powerpc wants to
avoid calculation of relative position to code.

As the timens_vdso_data is next page to vdso_data, provide
vdso_data pointer to __arch_get_timens_vdso_data() in order
to ease the calculation on powerpc in following patches.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/539c4204b1baa77c55f758904a1ea239abbc7a5c.1617209142.git.christophe.leroy@csgroup.eu
2021-04-14 23:04:44 +10:00
Jan Kiszka
f7b21a0e41 x86/asm: Ensure asm/proto.h can be included stand-alone
Fix:

  ../arch/x86/include/asm/proto.h:14:30: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
  long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
                               ^~~~~~~~~~~

  .../arch/x86/include/asm/proto.h:40:34: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
   long do_arch_prctl_common(struct task_struct *task, int option,
                                    ^~~~~~~~~~~

if linux/sched.h hasn't be included previously. This fixes a build error
when this header is used outside of the kernel tree.

 [ bp: Massage commit message. ]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/b76b4be3-cf66-f6b2-9a6c-3e7ef54f9845@web.de
2021-04-12 13:12:46 +02:00
Andrew Cooper
99cb64de36 x86/cpu: Comment Skylake server stepping too
Further to

  53375a5a21 ("x86/cpu: Resort and comment Intel models"),

CascadeLake and CooperLake are steppings of Skylake, and make up the 1st
to 3rd generation "Xeon Scalable Processor" line.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210409121027.16437-1-andrew.cooper3@citrix.com
2021-04-10 11:14:33 +02:00
Linus Torvalds
adb2c4174f Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
 "14 patches.

  Subsystems affected by this patch series: mm (kasan, gup, pagecache,
  and kfence), MAINTAINERS, mailmap, nds32, gcov, ocfs2, ia64, and lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS
  kfence, x86: fix preemptible warning on KPTI-enabled systems
  lib/test_kasan_module.c: suppress unused var warning
  kasan: fix conflict with page poisoning
  fs: direct-io: fix missing sdio->boundary
  ia64: fix user_stack_pointer() for ptrace()
  ocfs2: fix deadlock between setattr and dio_end_io_write
  gcov: re-fix clang-11+ support
  nds32: flush_dcache_page: use page_mapping_file to avoid races with swapoff
  mm/gup: check page posion status for coredump.
  .mailmap: fix old email addresses
  mailmap: update email address for Jordan Crouse
  treewide: change my e-mail address, fix my name
  MAINTAINERS: update CZ.NIC's Turris information
2021-04-09 17:06:32 -07:00
Marco Elver
6a77d38efc kfence, x86: fix preemptible warning on KPTI-enabled systems
On systems with KPTI enabled, we can currently observe the following
warning:

  BUG: using smp_processor_id() in preemptible
  caller is invalidate_user_asid+0x13/0x50
  CPU: 6 PID: 1075 Comm: dmesg Not tainted 5.12.0-rc4-gda4a2b1a5479-kfence_1+ #1
  Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012
  Call Trace:
   dump_stack+0x7f/0xad
   check_preemption_disabled+0xc8/0xd0
   invalidate_user_asid+0x13/0x50
   flush_tlb_one_kernel+0x5/0x20
   kfence_protect+0x56/0x80
   ...

While it normally makes sense to require preemption to be off, so that
the expected CPU's TLB is flushed and not another, in our case it really
is best-effort (see comments in kfence_protect_page()).

Avoid the warning by disabling preemption around flush_tlb_one_kernel().

Link: https://lore.kernel.org/lkml/YGIDBAboELGgMgXy@elver.google.com/
Link: https://lkml.kernel.org/r/20210330065737.652669-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-09 14:54:23 -07:00
Peter Zijlstra
53375a5a21 x86/cpu: Resort and comment Intel models
The INTEL_FAM6 list has become a mess again. Try and bring some sanity
back into it.

Where previously we had one microarch per year and a number of SKUs
within that, this no longer seems to be the case. We now get different
uarch names that share a 'core' design.

Add the core name starting at skylake and reorder to keep the cores
in chronological order. Furthermore, Intel marketed the names {Amber,
Coffee, Whiskey} Lake, but those are in fact steppings of Kaby Lake, add
comments for them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/YE+HhS8i0gshHD3W@hirez.programming.kicks-ass.net
2021-04-08 14:22:10 +02:00
Kees Cook
fe950f6020 x86/entry: Enable random_kstack_offset support
Allow for a randomized stack offset on a per-syscall basis, with roughly
5-6 bits of entropy, depending on compiler and word size. Since the
method of offsetting uses macros, this cannot live in the common entry
code (the stack offset needs to be retained for the life of the syscall,
which means it needs to happen at the actual entry point).

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210401232347.2791257-5-keescook@chromium.org
2021-04-08 14:05:20 +02:00
Vitaly Kuznetsov
fa26d0c778 ACPI: processor: Fix build when CONFIG_ACPI_PROCESSOR=m
Commit 8cdddd182b ("ACPI: processor: Fix CPU0 wakeup in
acpi_idle_play_dead()") tried to fix CPU0 hotplug breakage by copying
wakeup_cpu0() + start_cpu0() logic from hlt_play_dead()//mwait_play_dead()
into acpi_idle_play_dead(). The problem is that these functions are not
exported to modules so when CONFIG_ACPI_PROCESSOR=m build fails.

The issue could've been fixed by exporting both wakeup_cpu0()/start_cpu0()
(the later from assembly) but it seems putting the whole pattern into a
new function and exporting it instead is better.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 8cdddd182b ("CPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()")
Cc: <stable@vger.kernel.org> # 5.10+
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-04-07 19:02:43 +02:00
Sean Christopherson
b3754e5d3d x86/sgx: Move provisioning device creation out of SGX driver
And extract sgx_set_attribute() out of sgx_ioc_enclave_provision() and
export it as symbol for KVM to use.

The provisioning key is sensitive. The SGX driver only allows to create
an enclave which can access the provisioning key when the enclave
creator has permission to open /dev/sgx_provision. It should apply to
a VM as well, as the provisioning key is platform-specific, thus an
unrestricted VM can also potentially compromise the provisioning key.

Move the provisioning device creation out of sgx_drv_init() to
sgx_init() as a preparation for adding SGX virtualization support,
so that even if the SGX driver is not enabled due to flexible launch
control not being available, SGX virtualization can still be enabled,
and use it to restrict a VM's capability of being able to access the
provisioning key.

 [ bp: Massage commit message. ]

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/0f4d044d621561f26d5f4ef73e8dc6cd18cc7e79.1616136308.git.kai.huang@intel.com
2021-04-06 19:18:46 +02:00
Sean Christopherson
d155030b1e x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
The host kernel must intercept ECREATE to impose policies on guests, and
intercept EINIT to be able to write guest's virtual SGX_LEPUBKEYHASH MSR
values to hardware before running guest's EINIT so it can run correctly
according to hardware behavior.

Provide wrappers around __ecreate() and __einit() to hide the ugliness
of overloading the ENCLS return value to encode multiple error formats
in a single int.  KVM will trap-and-execute ECREATE and EINIT as part
of SGX virtualization, and reflect ENCLS execution result to guest by
setting up guest's GPRs, or on an exception, injecting the correct fault
based on return value of __ecreate() and __einit().

Use host userspace addresses (provided by KVM based on guest physical
address of ENCLS parameters) to execute ENCLS/EINIT when possible.
Accesses to both EPC and memory originating from ENCLS are subject to
segmentation and paging mechanisms.  It's also possible to generate
kernel mappings for ENCLS parameters by resolving PFN but using
__uaccess_xx() is simpler.

 [ bp: Return early if the __user memory accesses fail, use
   cpu_feature_enabled(). ]

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/20e09daf559aa5e9e680a0b4b5fba940f1bad86e.1616136308.git.kai.huang@intel.com
2021-04-06 19:18:27 +02:00
Sean Christopherson
32ddda8e44 x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT)
Define the ENCLS leafs that are available with SGX2, also referred to as
Enclave Dynamic Memory Management (EDMM).  The leafs will be used by KVM
to conditionally expose SGX2 capabilities to guests.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/5f0970c251ebcc6d5add132f0d750cc753b7060f.1616136308.git.kai.huang@intel.com
2021-04-06 09:43:42 +02:00
Sean Christopherson
9c55c78a73 x86/sgx: Move ENCLS leaf definitions to sgx.h
Move the ENCLS leaf definitions to sgx.h so that they can be used by
KVM.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/2e6cd7c5c1ced620cfcd292c3c6c382827fde6b2.1616136308.git.kai.huang@intel.com
2021-04-06 09:43:41 +02:00
Sean Christopherson
8ca52cc38d x86/sgx: Expose SGX architectural definitions to the kernel
Expose SGX architectural structures, as KVM will use many of the
architectural constants and structs to virtualize SGX.

Name the new header file as asm/sgx.h, rather than asm/sgx_arch.h, to
have single header to provide SGX facilities to share with other kernel
componments. Also update MAINTAINERS to include asm/sgx.h.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/6bf47acd91ab4d709e66ad1692c7803e4c9063a0.1616136308.git.kai.huang@intel.com
2021-04-06 09:43:41 +02:00
Peter Zijlstra
9bc0bb5072 objtool/x86: Rewrite retpoline thunk calls
When the compiler emits: "CALL __x86_indirect_thunk_\reg" for an
indirect call, have objtool rewrite it to:

	ALTERNATIVE "call __x86_indirect_thunk_\reg",
		    "call *%reg", ALT_NOT(X86_FEATURE_RETPOLINE)

Additionally, in order to not emit endless identical
.altinst_replacement chunks, use a global symbol for them, see
__x86_indirect_alt_*.

This also avoids objtool from having to do code generation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/20210326151300.320177914@infradead.org
2021-04-02 12:47:28 +02:00
Peter Zijlstra
119251855f x86/retpoline: Simplify retpolines
Due to:

  c9c324dc22 ("objtool: Support stack layout changes in alternatives")

it is now possible to simplify the retpolines.

Currently our retpolines consist of 2 symbols:

 - __x86_indirect_thunk_\reg: the compiler target
 - __x86_retpoline_\reg:  the actual retpoline.

Both are consecutive in code and aligned such that for any one register
they both live in the same cacheline:

  0000000000000000 <__x86_indirect_thunk_rax>:
   0:   ff e0                   jmpq   *%rax
   2:   90                      nop
   3:   90                      nop
   4:   90                      nop

  0000000000000005 <__x86_retpoline_rax>:
   5:   e8 07 00 00 00          callq  11 <__x86_retpoline_rax+0xc>
   a:   f3 90                   pause
   c:   0f ae e8                lfence
   f:   eb f9                   jmp    a <__x86_retpoline_rax+0x5>
  11:   48 89 04 24             mov    %rax,(%rsp)
  15:   c3                      retq
  16:   66 2e 0f 1f 84 00 00 00 00 00   nopw   %cs:0x0(%rax,%rax,1)

The thunk is an alternative_2, where one option is a JMP to the
retpoline. This was done so that objtool didn't need to deal with
alternatives with stack ops. But that problem has been solved, so now
it is possible to fold the entire retpoline into the alternative to
simplify and consolidate unused bytes:

  0000000000000000 <__x86_indirect_thunk_rax>:
   0:   ff e0                   jmpq   *%rax
   2:   90                      nop
   3:   90                      nop
   4:   90                      nop
   5:   90                      nop
   6:   90                      nop
   7:   90                      nop
   8:   90                      nop
   9:   90                      nop
   a:   90                      nop
   b:   90                      nop
   c:   90                      nop
   d:   90                      nop
   e:   90                      nop
   f:   90                      nop
  10:   90                      nop
  11:   66 66 2e 0f 1f 84 00 00 00 00 00        data16 nopw %cs:0x0(%rax,%rax,1)
  1c:   0f 1f 40 00             nopl   0x0(%rax)

Notice that since the longest alternative sequence is now:

   0:   e8 07 00 00 00          callq  c <.altinstr_replacement+0xc>
   5:   f3 90                   pause
   7:   0f ae e8                lfence
   a:   eb f9                   jmp    5 <.altinstr_replacement+0x5>
   c:   48 89 04 24             mov    %rax,(%rsp)
  10:   c3                      retq

17 bytes, we have 15 bytes NOP at the end of our 32 byte slot. (IOW, if
we can shrink the retpoline by 1 byte we can pack it more densely).

 [ bp: Massage commit message. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210326151259.506071949@infradead.org
2021-04-02 12:42:04 +02:00
Peter Zijlstra
23c1ad538f x86/alternatives: Optimize optimize_nops()
Currently, optimize_nops() scans to see if the alternative starts with
NOPs. However, the emit pattern is:

  141:	\oldinstr
  142:	.skip (len-(142b-141b)), 0x90

That is, when 'oldinstr' is short, the tail is padded with NOPs. This case
never gets optimized.

Rewrite optimize_nops() to replace any trailing string of NOPs inside
the alternative to larger NOPs. Also run it irrespective of patching,
replacing NOPs in both the original and replaced code.

A direct consequence is that 'padlen' becomes superfluous, so remove it.

 [ bp:
   - Adjust commit message
   - remove a stale comment about needing to pad
   - add a comment in optimize_nops()
   - exit early if the NOP verif. loop catches a mismatch - function
     should not not add NOPs in that case
   - fix the "optimized NOPs" offsets output ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210326151259.442992235@infradead.org
2021-04-02 12:41:17 +02:00
Ingo Molnar
b1f480bc06 Merge branch 'x86/cpu' into WIP.x86/core, to merge the NOP changes & resolve a semantic conflict
Conflict-merge this main commit in essence:

  a89dfde3dc: ("x86: Remove dynamic NOP selection")

With this upstream commit:

  b908297047: ("bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG")

Semantic merge conflict:

  arch/x86/net/bpf_jit_comp.c

  - memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
  + memcpy(prog, x86_nops[5], X86_PATCH_SIZE);

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-04-02 12:36:30 +02:00
Ingo Molnar
e855e80d00 Linux 5.12-rc5
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Merge tag 'v5.12-rc5' into WIP.x86/core, to pick up recent NOP related changes

In particular we want to have this upstream commit:

  b908297047: ("bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG")

... before merging in x86/cpu changes and the removal of the NOP optimizations, and
applying PeterZ's !retpoline objtool series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-04-02 12:33:16 +02:00
Vitaly Kuznetsov
8cdddd182b ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()
Commit 496121c021 ("ACPI: processor: idle: Allow probing on platforms
with one ACPI C-state") broke CPU0 hotplug on certain systems, e.g.
I'm observing the following on AWS Nitro (e.g r5b.xlarge but other
instance types are affected as well):

 # echo 0 > /sys/devices/system/cpu/cpu0/online
 # echo 1 > /sys/devices/system/cpu/cpu0/online
 <10 seconds delay>
 -bash: echo: write error: Input/output error

In fact, the above mentioned commit only revealed the problem and did
not introduce it. On x86, to wakeup CPU an NMI is being used and
hlt_play_dead()/mwait_play_dead() loops are prepared to handle it:

	/*
	 * If NMI wants to wake up CPU0, start CPU0.
	 */
	if (wakeup_cpu0())
		start_cpu0();

cpuidle_play_dead() -> acpi_idle_play_dead() (which is now being called on
systems where it wasn't called before the above mentioned commit) serves
the same purpose but it doesn't have a path for CPU0. What happens now on
wakeup is:
 - NMI is sent to CPU0
 - wakeup_cpu0_nmi() works as expected
 - we get back to while (1) loop in acpi_idle_play_dead()
 - safe_halt() puts CPU0 to sleep again.

The straightforward/minimal fix is add the special handling for CPU0 on x86
and that's what the patch is doing.

Fixes: 496121c021 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-04-01 13:37:55 +02:00
Borislav Petkov
f2ac256b9a Merge 'x86/alternatives'
Pick up dependent changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
2021-03-31 18:04:19 +02:00
Peter Zijlstra
52fa82c21f x86: Add insn_decode_kernel()
Add a helper to decode kernel instructions; there's no point in
endlessly repeating those last two arguments.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210326151259.379242587@infradead.org
2021-03-31 16:20:22 +02:00
Ingo Molnar
feecb81732 Linux 5.12-rc5
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Merge tag 'v5.12-rc5' into locking/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-03-29 15:56:48 +02:00