Commit Graph

11387 Commits

Author SHA1 Message Date
Linus Torvalds
efb2883060 Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
Pull turbostat updates from Len Brown:
 "Only updating the turbostat tool here, no kernel changes"

* 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  tools/power turbostat: version 2022.07.28
  tools/power turbostat: do not decode ACC for ICX and SPR
  tools/power turbostat: fix SPR PC6 limits
  tools/power turbostat: cleanup 'automatic_cstate_conversion_probe()'
  tools/power turbostat: separate SPR from ICX
  tools/power turbosstat: fix comment
  tools/power turbostat: Support RAPTORLAKE P
  tools/power turbostat: add support for ALDERLAKE_N
  tools/power turbostat: dump secondary Turbo-Ratio-Limit
  tools/power turbostat: simplify dump_turbo_ratio_limits()
  tools/power turbostat: dump CPUID.7.EDX.Hybrid
  tools/power turbostat: update turbostat.8
  tools/power turbostat: Show uncore frequency
  tools/power turbostat: Fix file pointer leak
  tools/power turbostat: replace strncmp with single character compare
  tools/power turbostat: print the kernel boot commandline
  tools/power turbostat: Introduce support for RaptorLake
2022-08-02 12:47:31 -07:00
Linus Torvalds
63e6053add Merge tag 'perf-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events updates from Ingo Molnar:

 - Fix Intel Alder Lake PEBS memory access latency & data source
   profiling info bugs.

 - Use Intel large-PEBS hardware feature in more circumstances, to
   reduce PMI overhead & reduce sampling data.

 - Extend the lost-sample profiling output with the PERF_FORMAT_LOST ABI
   variant, which tells tooling the exact number of samples lost.

 - Add new IBS register bits definitions.

 - AMD uncore events: Add PerfMonV2 DF (Data Fabric) enhancements.

* tag 'perf-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/ibs: Add new IBS register bits into header
  perf/x86/intel: Fix PEBS data source encoding for ADL
  perf/x86/intel: Fix PEBS memory access info encoding for ADL
  perf/core: Add a new read format to get a number of lost samples
  perf/x86/amd/uncore: Add PerfMonV2 RDPMC assignments
  perf/x86/amd/uncore: Add PerfMonV2 DF event format
  perf/x86/amd/uncore: Detect available DF counters
  perf/x86/amd/uncore: Use attr_update for format attributes
  perf/x86/amd/uncore: Use dynamic events array
  x86/events/intel/ds: Enable large PEBS for PERF_SAMPLE_WEIGHT_TYPE
2022-08-01 12:24:30 -07:00
Linus Torvalds
ecf9b7bfea Merge tag 'x86_core_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:

 - Have invalid MSR accesses warnings appear only once after a
   pr_warn_once() change broke that

 - Simplify {JMP,CALL}_NOSPEC and let the objtool retpoline patching
   infra take care of them instead of having unreadable alternative
   macros there

* tag 'x86_core_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/extable: Fix ex_handler_msr() print condition
  x86,nospec: Simplify {JMP,CALL}_NOSPEC
2022-08-01 10:04:00 -07:00
Linus Torvalds
42efa5e3a8 Merge tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:

 - Remove the vendor check when selecting MWAIT as the default idle
   state

 - Respect idle=nomwait when supplied on the kernel cmdline

 - Two small cleanups

* tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Use MSR_IA32_MISC_ENABLE constants
  x86: Fix comment for X86_FEATURE_ZEN
  x86: Remove vendor checks from prefer_mwait_c1_over_halt
  x86: Handle idle=nomwait cmdline properly for x86_idle
2022-08-01 09:49:29 -07:00
Linus Torvalds
650ea1f626 Merge tag 'x86_fpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu update from Borislav Petkov:

 - Add machinery to initialize AMX register state in order for
   AMX-capable CPUs to be able to enter deeper low-power state

* tag 'x86_fpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  intel_idle: Add a new flag to initialize the AMX state
  x86/fpu: Add a helper to prepare AMX state for low-power CPU idle
2022-08-01 09:36:18 -07:00
Linus Torvalds
92598ae22f Merge tag 'x86_mm_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Borislav Petkov:

 - Rename a PKRU macro to make more sense when reading the code

 - Update pkeys documentation

 - Avoid reading contended mm's TLB generation var if not absolutely
   necessary along with fixing a case where arch_tlbbatch_flush()
   doesn't adhere to the generation scheme and thus violates the
   conditions for the above avoidance.

* tag 'x86_mm_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/tlb: Ignore f->new_tlb_gen when zero
  x86/pkeys: Clarify PKRU_AD_KEY macro
  Documentation/protection-keys: Clean up documentation for User Space pkeys
  x86/mm/tlb: Avoid reading mm_tlb_gen when possible
2022-08-01 09:34:39 -07:00
Len Brown
4af184ee8b tools/power turbostat: dump secondary Turbo-Ratio-Limit
Intel Performance Hybrid processors have a 2nd MSR
describing the turbo limits enforced on the Ecores.

Note, TRL and Secondary-TRL are usually R/O information,
but on overclock-capable parts, they can be written.

Signed-off-by: Len Brown <len.brown@intel.com>
2022-07-28 14:23:26 -04:00
Borislav Petkov
5bb6c1d112 Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV"
This reverts commit 007faec014.

Now that hyperv does its own protocol negotiation:

  49d6a3c062 ("x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM")

revert this exposure of the sev_es_ghcb_hv_call() helper.

Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by:Tianyu Lan <tiala@microsoft.com>
Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com
2022-07-27 18:09:13 +02:00
Ravi Bangoria
326ecc15c6 perf/x86/ibs: Add new IBS register bits into header
IBS support has been enhanced with two new features in upcoming uarch:

  1. DataSrc extension and
  2. L3 miss filtering.

Additional set of bits has been introduced in IBS registers to use these
features. Define these new bits into arch/x86/ header.

  [ bp: Massage commit message. ]

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20220604044519.594-7-ravi.bangoria@amd.com
2022-07-27 13:54:38 +02:00
Linus Torvalds
05017fed92 Merge tag 'x86_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
 "A couple more retbleed fallout fixes.

  It looks like their urgency is decreasing so it seems like we've
  managed to catch whatever snafus the limited -rc testing has exposed.
  Maybe we're getting ready... :)

   - Make retbleed mitigations 64-bit only (32-bit will need a bit more
     work if even needed, at all).

   - Prevent return thunks patching of the LKDTM modules as it is not
     needed there

   - Avoid writing the SPEC_CTRL MSR on every kernel entry on eIBRS
     parts

   - Enhance error output of apply_returns() when it fails to patch a
     return thunk

   - A sparse fix to the sev-guest module

   - Protect EFI fw calls by issuing an IBPB on AMD"

* tag 'x86_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Make all RETbleed mitigations 64-bit only
  lkdtm: Disable return thunks in rodata.c
  x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts
  x86/alternative: Report missing return thunk details
  virt: sev-guest: Pass the appropriate argument type to iounmap()
  x86/amd: Use IBPB for firmware calls
2022-07-24 09:40:17 -07:00
Peter Zijlstra
1e9fdf21a4 mmu_gather: Remove per arch tlb_{start,end}_vma()
Scattered across the archs are 3 basic forms of tlb_{start,end}_vma().
Provide two new MMU_GATHER_knobs to enumerate them and remove the per
arch tlb_{start,end}_vma() implementations.

 - MMU_GATHER_NO_FLUSH_CACHE indicates the arch has flush_cache_range()
   but does *NOT* want to call it for each VMA.

 - MMU_GATHER_MERGE_VMAS indicates the arch wants to merge the
   invalidate across multiple VMAs if possible.

With these it is possible to capture the three forms:

  1) empty stubs;
     select MMU_GATHER_NO_FLUSH_CACHE and MMU_GATHER_MERGE_VMAS

  2) start: flush_cache_range(), end: empty;
     select MMU_GATHER_MERGE_VMAS

  3) start: flush_cache_range(), end: flush_tlb_range();
     default

Obviously, if the architecture does not have flush_cache_range() then
it also doesn't need to select MMU_GATHER_NO_FLUSH_CACHE.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-07-21 10:50:13 -07:00
Peter Zijlstra
09d09531a5 x86,nospec: Simplify {JMP,CALL}_NOSPEC
Have {JMP,CALL}_NOSPEC generate the same code GCC does for indirect
calls and rely on the objtool retpoline patching infrastructure.

There's no reason these should be alternatives while the vast bulk of
compiler generated retpolines are not.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2022-07-21 10:39:42 +02:00
Chang S. Bae
f17b168734 x86/fpu: Add a helper to prepare AMX state for low-power CPU idle
When a CPU enters an idle state, a non-initialized AMX register state may
be the cause of preventing a deeper low-power state. Other extended
register states whether initialized or not do not impact the CPU idle
state.

The new helper can ensure the AMX state is initialized before the CPU is
idle, and it will be used by the intel idle driver.

Check the AMX_TILE feature bit before using XGETBV1 as a chain of
dependencies was established via cpuid_deps[]: AMX->XFD->XGETBV1.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20220608164748.11864-2-chang.seok.bae@intel.com
2022-07-19 18:46:15 +02:00
Nadav Amit
8f1d56f64f x86/mm/tlb: Ignore f->new_tlb_gen when zero
Commit aa44284960 ("x86/mm/tlb: Avoid reading mm_tlb_gen when
possible") introduced an optimization to skip superfluous TLB
flushes based on the generation provided in flush_tlb_info.

However, arch_tlbbatch_flush() does not provide any generation in
flush_tlb_info and populates the flush_tlb_info generation with
0.  This 0 is causes the flush_tlb_info to be interpreted as a
superfluous, old flush.  As a result, try_to_unmap_one() would
not perform any TLB flushes.

Fix it by checking whether f->new_tlb_gen is nonzero. Zero value
is anyhow is an invalid generation value. To avoid future
confusion, introduce TLB_GENERATION_INVALID constant and use it
properly. Add warnings to ensure no partial flushes are done with
TLB_GENERATION_INVALID or when f->mm is NULL, since this does not
make any sense.

In addition, add the missing unlikely().

[ dhansen: change VM_BUG_ON() -> VM_WARN_ON(), clarify changelog ]

Fixes: aa44284960 ("x86/mm/tlb: Avoid reading mm_tlb_gen when possible")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Hugh Dickins <hughd@google.com>
Link: https://lkml.kernel.org/r/20220710232837.3618-1-namit@vmware.com
2022-07-19 09:04:52 -07:00
Peter Zijlstra
28a99e95f5 x86/amd: Use IBPB for firmware calls
On AMD IBRS does not prevent Retbleed; as such use IBPB before a
firmware call to flush the branch history state.

And because in order to do an EFI call, the kernel maps a whole lot of
the kernel page table into the EFI page table, do an IBPB just in case
in order to prevent the scenario of poisoning the BTB and causing an EFI
call using the unprotected RET there.

  [ bp: Massage. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220715194550.793957-1-cascardo@canonical.com
2022-07-18 15:38:09 +02:00
Nathan Chancellor
db88697968 x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current
Clang warns:

  arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection]
  DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
                      ^
  arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here
  extern u64 x86_spec_ctrl_current;
             ^
  1 error generated.

The declaration should be using DECLARE_PER_CPU instead so all
attributes stay in sync.

Cc: stable@vger.kernel.org
Fixes: fc02735b14 ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-07-14 14:52:43 -07:00
Linus Torvalds
ce114c8668 Merge tag 'x86_bugs_retbleed' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 retbleed fixes from Borislav Petkov:
 "Just when you thought that all the speculation bugs were addressed and
  solved and the nightmare is complete, here's the next one: speculating
  after RET instructions and leaking privileged information using the
  now pretty much classical covert channels.

  It is called RETBleed and the mitigation effort and controlling
  functionality has been modelled similar to what already existing
  mitigations provide"

* tag 'x86_bugs_retbleed' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  x86/speculation: Disable RRSBA behavior
  x86/kexec: Disable RET on kexec
  x86/bugs: Do not enable IBPB-on-entry when IBPB is not supported
  x86/entry: Move PUSH_AND_CLEAR_REGS() back into error_entry
  x86/bugs: Add Cannon lake to RETBleed affected CPU list
  x86/retbleed: Add fine grained Kconfig knobs
  x86/cpu/amd: Enumerate BTC_NO
  x86/common: Stamp out the stepping madness
  KVM: VMX: Prevent RSB underflow before vmenter
  x86/speculation: Fill RSB on vmexit for IBRS
  KVM: VMX: Fix IBRS handling after vmexit
  KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS
  KVM: VMX: Convert launched argument to flags
  KVM: VMX: Flatten __vmx_vcpu_run()
  objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
  x86/speculation: Remove x86_spec_ctrl_mask
  x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit
  x86/speculation: Fix SPEC_CTRL write on SMT state change
  x86/speculation: Fix firmware entry SPEC_CTRL handling
  x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
  ...
2022-07-11 18:15:25 -07:00
Pawan Gupta
4ad3278df6 x86/speculation: Disable RRSBA behavior
Some Intel processors may use alternate predictors for RETs on
RSB-underflow. This condition may be vulnerable to Branch History
Injection (BHI) and intramode-BTI.

Kernel earlier added spectre_v2 mitigation modes (eIBRS+Retpolines,
eIBRS+LFENCE, Retpolines) which protect indirect CALLs and JMPs against
such attacks. However, on RSB-underflow, RET target prediction may
fallback to alternate predictors. As a result, RET's predicted target
may get influenced by branch history.

A new MSR_IA32_SPEC_CTRL bit (RRSBA_DIS_S) controls this fallback
behavior when in kernel mode. When set, RETs will not take predictions
from alternate predictors, hence mitigating RETs as well. Support for
this is enumerated by CPUID.7.2.EDX[RRSBA_CTRL] (bit2).

For spectre v2 mitigation, when a user selects a mitigation that
protects indirect CALLs and JMPs against BHI and intramode-BTI, set
RRSBA_DIS_S also to protect RETs for RSB-underflow case.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-07-09 13:12:45 +02:00
Juergen Gross
96e8fc5818 x86/xen: Use clear_bss() for Xen PV guests
Instead of clearing the bss area in assembly code, use the clear_bss()
function.

This requires to pass the start_info address as parameter to
xen_start_kernel() in order to avoid the xen_start_info being zeroed
again.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20220630071441.28576-2-jgross@suse.com
2022-07-01 10:57:52 +02:00
Peter Zijlstra
f43b9876e8 x86/retbleed: Add fine grained Kconfig knobs
Do fine-grained Kconfig for all the various retbleed parts.

NOTE: if your compiler doesn't support return thunks this will
silently 'upgrade' your mitigation to IBPB, you might not like this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-29 17:43:41 +02:00
Andrew Cooper
26aae8ccbc x86/cpu/amd: Enumerate BTC_NO
BTC_NO indicates that hardware is not susceptible to Branch Type Confusion.

Zen3 CPUs don't suffer BTC.

Hypervisors are expected to synthesise BTC_NO when it is appropriate
given the migration pool, to prevent kernels using heuristics.

  [ bp: Massage. ]

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:01 +02:00
Josh Poimboeuf
9756bba284 x86/speculation: Fill RSB on vmexit for IBRS
Prevent RSB underflow/poisoning attacks with RSB.  While at it, add a
bunch of comments to attempt to document the current state of tribal
knowledge about RSB attacks and what exactly is being mitigated.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Josh Poimboeuf
fc02735b14 KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS
On eIBRS systems, the returns in the vmexit return path from
__vmx_vcpu_run() to vmx_vcpu_run() are exposed to RSB poisoning attacks.

Fix that by moving the post-vmexit spec_ctrl handling to immediately
after the vmexit.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Josh Poimboeuf
8faea26e61 objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
Commit

  c536ed2fff ("objtool: Remove SAVE/RESTORE hints")

removed the save/restore unwind hints because they were no longer
needed. Now they're going to be needed again so re-add them.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Josh Poimboeuf
e6aa13622e x86/speculation: Fix firmware entry SPEC_CTRL handling
The firmware entry code may accidentally clear STIBP or SSBD. Fix that.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Josh Poimboeuf
b2620facef x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants
to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be
silently disabled.

There's nothing retpoline-specific about RSB buffer filling.  Remove the
CONFIG_RETPOLINE guards around it.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Peter Zijlstra
d7caac991f x86/cpu/amd: Add Spectral Chicken
Zen2 uarchs have an undocumented, unnamed, MSR that contains a chicken
bit for some speculation behaviour. It needs setting.

Note: very belatedly AMD released naming; it's now officially called
      MSR_AMD64_DE_CFG2 and MSR_AMD64_DE_CFG2_SUPPRESS_NOBR_PRED_BIT
      but shall remain the SPECTRAL CHICKEN.

Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Peter Zijlstra
a09a6e2399 objtool: Add entry UNRET validation
Since entry asm is tricky, add a validation pass that ensures the
retbleed mitigation has been done before the first actual RET
instruction.

Entry points are those that either have UNWIND_HINT_ENTRY, which acts
as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or
those that have UWIND_HINT_IRET_REGS at +0.

This is basically a variant of validate_branch() that is
intra-function and it will simply follow all branches from marked
entry points and ensures that all paths lead to ANNOTATE_UNRET_END.

If a path hits RET or an indirection the path is a fail and will be
reported.

There are 3 ANNOTATE_UNRET_END instances:

 - UNTRAIN_RET itself
 - exception from-kernel; this path doesn't need UNTRAIN_RET
 - all early exceptions; these also don't need UNTRAIN_RET

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Peter Zijlstra
3ebc170068 x86/bugs: Add retbleed=ibpb
jmp2ret mitigates the easy-to-attack case at relatively low overhead.
It mitigates the long speculation windows after a mispredicted RET, but
it does not mitigate the short speculation window from arbitrary
instruction boundaries.

On Zen2, there is a chicken bit which needs setting, which mitigates
"arbitrary instruction boundaries" down to just "basic block boundaries".

But there is no fix for the short speculation window on basic block
boundaries, other than to flush the entire BTB to evict all attacker
predictions.

On the spectrum of "fast & blurry" -> "safe", there is (on top of STIBP
or no-SMT):

  1) Nothing		System wide open
  2) jmp2ret		May stop a script kiddy
  3) jmp2ret+chickenbit  Raises the bar rather further
  4) IBPB		Only thing which can count as "safe".

Tentative numbers put IBPB-on-entry at a 2.5x hit on Zen2, and a 10x hit
on Zen1 according to lmbench.

  [ bp: Fixup feature bit comments, document option, 32-bit build fix. ]

Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:34:00 +02:00
Peter Zijlstra
9bb2ec608a objtool: Update Retpoline validation
Update retpoline validation with the new CONFIG_RETPOLINE requirement of
not having bare naked RET instructions.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
bf5835bcdb intel_idle: Disable IBRS during long idle
Having IBRS enabled while the SMT sibling is idle unnecessarily slows
down the running sibling. OTOH, disabling IBRS around idle takes two
MSR writes, which will increase the idle latency.

Therefore, only disable IBRS around deeper idle states. Shallow idle
states are bounded by the tick in duration, since NOHZ is not allowed
for them by virtue of their short target residency.

Only do this for mwait-driven idle, since that keeps interrupts disabled
across idle, which makes disabling IBRS vs IRQ-entry a non-issue.

Note: C6 is a random threshold, most importantly C1 probably shouldn't
disable IBRS, benchmarking needed.

Suggested-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
6ad0ad2bf8 x86/bugs: Report Intel retbleed vulnerability
Skylake suffers from RSB underflow speculation issues; report this
vulnerability and it's mitigation (spectre_v2=ibrs).

  [jpoimboe: cleanups, eibrs]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Pawan Gupta
7c693f54c8 x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS
Extend spectre_v2= boot option with Kernel IBRS.

  [jpoimboe: no STIBP with IBRS]

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
c779bc1a90 x86/bugs: Optimize SPEC_CTRL MSR writes
When changing SPEC_CTRL for user control, the WRMSR can be delayed
until return-to-user when KERNEL_IBRS has been enabled.

This avoids an MSR write during context switch.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
2dbb887e87 x86/entry: Add kernel IBRS implementation
Implement Kernel IBRS - currently the only known option to mitigate RSB
underflow speculation issues on Skylake hardware.

Note: since IBRS_ENTER requires fuller context established than
UNTRAIN_RET, it must be placed after it. However, since UNTRAIN_RET
itself implies a RET, it must come after IBRS_ENTER. This means
IBRS_ENTER needs to also move UNTRAIN_RET.

Note 2: KERNEL_IBRS is sub-optimal for XenPV.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
caa0ff24d5 x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value
Due to TIF_SSBD and TIF_SPEC_IB the actual IA32_SPEC_CTRL value can
differ from x86_spec_ctrl_base. As such, keep a per-CPU value
reflecting the current task's MSR content.

  [jpoimboe: rename]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Alexandre Chartre
6b80b59b35 x86/bugs: Report AMD retbleed vulnerability
Report that AMD x86 CPUs are vulnerable to the RETBleed (Arbitrary
Speculative Code Execution with Return Instructions) attack.

  [peterz: add hygon]
  [kim: invert parity; fam15h]

Co-developed-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
a149180fbc x86: Add magic AMD return-thunk
Note: needs to be in a section distinct from Retpolines such that the
Retpoline RET substitution cannot possibly use immediate jumps.

ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a
little tricky but works due to the fact that zen_untrain_ret() doesn't
have any stack ops and as such will emit a single ORC entry at the
start (+0x3f).

Meanwhile, unwinding an IP, including the __x86_return_thunk() one
(+0x40) will search for the largest ORC entry smaller or equal to the
IP, these will find the one ORC entry (+0x3f) and all works.

  [ Alexandre: SVM part. ]
  [ bp: Build fix, massages. ]

Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
aa3d480315 x86: Use return-thunk in asm code
Use the return thunk in asm code. If the thunk isn't needed, it will
get patched into a RET instruction during boot by apply_returns().

Since alternatives can't handle relocations outside of the first
instruction, putting a 'jmp __x86_return_thunk' in one is not valid,
therefore carve out the memmove ERMS path into a separate label and jump
to it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Peter Zijlstra
ee88d363d1 x86,static_call: Use alternative RET encoding
In addition to teaching static_call about the new way to spell 'RET',
there is an added complication in that static_call() is allowed to
rewrite text before it is known which particular spelling is required.

In order to deal with this; have a static_call specific fixup in the
apply_return() 'alternative' patching routine that will rewrite the
static_call trampoline to match the definite sequence.

This in turn creates the problem of uniquely identifying static call
trampolines. Currently trampolines are 8 bytes, the first 5 being the
jmp.d32/ret sequence and the final 3 a byte sequence that spells out
'SCT'.

This sequence is used in __static_call_validate() to ensure it is
patching a trampoline and not a random other jmp.d32. That is,
false-positives shouldn't be plenty, but aren't a big concern.

OTOH the new __static_call_fixup() must not have false-positives, and
'SCT' decodes to the somewhat weird but semi plausible sequence:

  push %rbx
  rex.XB push %r12

Additionally, there are SLS concerns with immediate jumps. Combined it
seems like a good moment to change the signature to a single 3 byte
trap instruction that is unique to this usage and will not ever get
generated by accident.

As such, change the signature to: '0x0f, 0xb9, 0xcc', which decodes
to:

  ud1 %esp, %ecx

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Peter Zijlstra
15e67227c4 x86: Undo return-thunk damage
Introduce X86_FEATURE_RETHUNK for those afflicted with needing this.

  [ bp: Do only INT3 padding - simpler. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Peter Zijlstra
0b53c374b9 x86/retpoline: Use -mfunction-return
Utilize -mfunction-return=thunk-extern when available to have the
compiler replace RET instructions with direct JMPs to the symbol
__x86_return_thunk. This does not affect assembler (.S) sources, only C
sources.

-mfunction-return=thunk-extern has been available since gcc 7.3 and
clang 15.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Peter Zijlstra
369ae6ffc4 x86/retpoline: Cleanup some #ifdefery
On it's own not much of a cleanup but it prepares for more/similar
code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Peter Zijlstra
a883d624ae x86/cpufeatures: Move RETPOLINE flags to word 11
In order to extend the RETPOLINE features to 4, move them to word 11
where there is still room. This mostly keeps DISABLE_RETPOLINE
simple.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:58 +02:00
Linus Torvalds
ca1fdab7fd Merge tag 'efi-urgent-for-v5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI fixes from Ard Biesheuvel:

 - remove pointless include of asm/efi.h, which does not exist on ia64

 - fix DXE service marshalling prototype for mixed mode

* tag 'efi-urgent-for-v5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/x86: libstub: Fix typo in __efi64_argmap* name
  efi: sysfb_efi: remove unnecessary <asm/efi.h> include
2022-06-21 12:20:11 -05:00
Evgeniy Baskov
aa6d1ed107 efi/x86: libstub: Fix typo in __efi64_argmap* name
The actual name of the DXE services function used
is set_memory_space_attributes(), not set_memory_space_descriptor().

Change EFI mixed mode helper macro name to match the function name.

Fixes: 31f1a0edff ("efi/x86: libstub: Make DXE calls mixed mode safe")
Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-06-21 18:11:46 +02:00
Linus Torvalds
05c6ca8512 Merge tag 'x86-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:

 - Make RESERVE_BRK() work again with older binutils. The recent
   'simplification' broke that.

 - Make early #VE handling increment RIP when successful.

 - Make the #VE code consistent vs. the RIP adjustments and add
   comments.

 - Handle load_unaligned_zeropad() across page boundaries correctly in
   #VE when the second page is shared.

* tag 'x86-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page
  x86/tdx: Clarify RIP adjustments in #VE handler
  x86/tdx: Fix early #VE handling
  x86/mm: Fix RESERVE_BRK() for older binutils
2022-06-19 09:58:28 -05:00
Linus Torvalds
32efdbffff Merge tag 'pci-v5.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull pci fix from Bjorn Helgaas:
 "Revert clipping of PCI host bridge windows to avoid E820 regions,
  which broke several machines by forcing unnecessary BAR reassignments
  (Hans de Goede)"

* tag 'pci-v5.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  x86/PCI: Revert "x86/PCI: Clip only host bridge windows for E820 regions"
2022-06-17 15:12:20 -05:00
Hans de Goede
a2b36ffbf5 x86/PCI: Revert "x86/PCI: Clip only host bridge windows for E820 regions"
This reverts commit 4c5e242d3e.

Prior to 4c5e242d3e ("x86/PCI: Clip only host bridge windows for E820
regions"), E820 regions did not affect PCI host bridge windows.  We only
looked at E820 regions and avoided them when allocating new MMIO space.
If firmware PCI bridge window and BAR assignments used E820 regions, we
left them alone.

After 4c5e242d3e, we removed E820 regions from the PCI host bridge
windows before looking at BARs, so firmware assignments in E820 regions
looked like errors, and we moved things around to fit in the space left
(if any) after removing the E820 regions.  This unnecessary BAR
reassignment broke several machines.

Guilherme reported that Steam Deck fails to boot after 4c5e242d3e.  We
clipped the window that contained most 32-bit BARs:

  BIOS-e820: [mem 0x00000000a0000000-0x00000000a00fffff] reserved
  acpi PNP0A08:00: clipped [mem 0x80000000-0xf7ffffff window] to [mem 0xa0100000-0xf7ffffff window] for e820 entry [mem 0xa0000000-0xa00fffff]

which forced us to reassign all those BARs, for example, this NVMe BAR:

  pci 0000:00:01.2: PCI bridge to [bus 01]
  pci 0000:00:01.2:   bridge window [mem 0x80600000-0x806fffff]
  pci 0000:01:00.0: BAR 0: [mem 0x80600000-0x80603fff 64bit]
  pci 0000:00:01.2: can't claim window [mem 0x80600000-0x806fffff]: no compatible bridge window
  pci 0000:01:00.0: can't claim BAR 0 [mem 0x80600000-0x80603fff 64bit]: no compatible bridge window

  pci 0000:00:01.2: bridge window: assigned [mem 0xa0100000-0xa01fffff]
  pci 0000:01:00.0: BAR 0: assigned [mem 0xa0100000-0xa0103fff 64bit]

All the reassignments were successful, so the devices should have been
functional at the new addresses, but some were not.

Andy reported a similar failure on an Intel MID platform.  Benjamin
reported a similar failure on a VMWare Fusion VM.

Note: this is not a clean revert; this revert keeps the later change to
make the clipping dependent on a new pci_use_e820 bool, moving the checking
of this bool to arch_remove_reservations().

[bhelgaas: commit log, add more reporters and testers]
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216109
Reported-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reported-by: Benjamin Coddington <bcodding@redhat.com>
Reported-by: Jongman Heo <jongman.heo@gmail.com>
Fixes: 4c5e242d3e ("x86/PCI: Clip only host bridge windows for E820 regions")
Link: https://lore.kernel.org/r/20220612144325.85366-1-hdegoede@redhat.com
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-06-17 14:24:14 -05:00
Linus Torvalds
2d806a688f Merge tag 'hyperv-fixes-signed-20220617' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:

 - Fix hv_init_clocksource annotation (Masahiro Yamada)

 - Two bug fixes for vmbus driver (Saurabh Sengar)

 - Fix SEV negotiation (Tianyu Lan)

 - Fix comments in code (Xiang Wang)

 - One minor fix to HID driver (Michael Kelley)

* tag 'hyperv-fixes-signed-20220617' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM
  Drivers: hv: vmbus: Release cpu lock in error case
  HID: hyperv: Correctly access fields declared as __le16
  clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()
  Drivers: hv: Fix syntax errors in comments
  Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs
2022-06-17 13:39:12 -05:00