linux.git/arch/x86/include/asm, branch v6.18 Linux kernel source tree Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2025-11-14T23:39:39+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-11-14T23:39:39+00:00 cbba5d1b53fb82209feacb459edecb1ef8427119 Pull bpf fixes from Alexei Starovoitov: - Fix interaction between livepatch and BPF fexit programs (Song Liu) With Steven and Masami acks. - Fix stack ORC unwind from BPF kprobe_multi (Jiri Olsa) With Steven and Masami acks. - Fix out of bounds access in widen_imprecise_scalars() in the verifier (Eduard Zingerman) - Fix conflicts between MPTCP and BPF sockmap (Jiayuan Chen) - Fix net_sched storage collision with BPF data_meta/data_end (Eric Dumazet) - Add _impl suffix to BPF kfuncs with implicit args to avoid breaking them in bpf-next when KF_IMPLICIT_ARGS is added (Mykyta Yatsenko) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: selftests/bpf: Test widen_imprecise_scalars() with different stack depth bpf: account for current allocated stack depth in widen_imprecise_scalars() bpf: Add bpf_prog_run_data_pointers() selftests/bpf: Add mptcp test with sockmap mptcp: Fix proto fallback detection with BPF mptcp: Disallow MPTCP subflows from sockmap selftests/bpf: Add stacktrace ips test for raw_tp selftests/bpf: Add stacktrace ips test for kprobe_multi/kretprobe_multi x86/fgraph,bpf: Fix stack ORC unwind from kprobe_multi return probe Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()" bpf: add _impl suffix for bpf_stream_vprintk() kfunc bpf:add _impl suffix for bpf_task_work_schedule* kfuncs selftests/bpf: Add tests for livepatch + bpf trampoline ftrace: bpf: Fix IPMODIFY + DIRECT in modify_ftrace_direct() ftrace: Fix BPF fexit with livepatch 
Pull bpf fixes from Alexei Starovoitov:

 - Fix interaction between livepatch and BPF fexit programs (Song Liu)
   With Steven and Masami acks.

 - Fix stack ORC unwind from BPF kprobe_multi (Jiri Olsa)
   With Steven and Masami acks.

 - Fix out of bounds access in widen_imprecise_scalars() in the verifier
   (Eduard Zingerman)

 - Fix conflicts between MPTCP and BPF sockmap (Jiayuan Chen)

 - Fix net_sched storage collision with BPF data_meta/data_end (Eric
   Dumazet)

 - Add _impl suffix to BPF kfuncs with implicit args to avoid breaking
   them in bpf-next when KF_IMPLICIT_ARGS is added (Mykyta Yatsenko)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Test widen_imprecise_scalars() with different stack depth
  bpf: account for current allocated stack depth in widen_imprecise_scalars()
  bpf: Add bpf_prog_run_data_pointers()
  selftests/bpf: Add mptcp test with sockmap
  mptcp: Fix proto fallback detection with BPF
  mptcp: Disallow MPTCP subflows from sockmap
  selftests/bpf: Add stacktrace ips test for raw_tp
  selftests/bpf: Add stacktrace ips test for kprobe_multi/kretprobe_multi
  x86/fgraph,bpf: Fix stack ORC unwind from kprobe_multi return probe
  Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()"
  bpf: add _impl suffix for bpf_stream_vprintk() kfunc
  bpf:add _impl suffix for bpf_task_work_schedule* kfuncs
  selftests/bpf: Add tests for livepatch + bpf trampoline
  ftrace: bpf: Fix IPMODIFY + DIRECT in modify_ftrace_direct()
  ftrace: Fix BPF fexit with livepatch
Merge tag 'x86-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2025-11-08T17:01:11+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-11-08T17:01:11+00:00 0d7bee10beeb59b1133bf5a4749b17a4ef3bbb01 Pull x86 fixes from Ingo Molnar: - Fix AMD PCI root device caching regression that triggers on certain firmware variants - Fix the zen5_rdseed_microcode[] array to be NULL-terminated - Add more AMD models to microcode signature checking * tag 'x86-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/microcode/AMD: Add more known models to entry sign checking x86/CPU/AMD: Add missing terminator for zen5_rdseed_microcode x86/amd_node: Fix AMD root device caching 
Pull x86 fixes from Ingo Molnar:

 - Fix AMD PCI root device caching regression that triggers
   on certain firmware variants

 - Fix the zen5_rdseed_microcode[] array to be NULL-terminated

 - Add more AMD models to microcode signature checking

* tag 'x86-urgent-2025-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode/AMD: Add more known models to entry sign checking
  x86/CPU/AMD: Add missing terminator for zen5_rdseed_microcode
  x86/amd_node: Fix AMD root device caching
x86/fgraph,bpf: Fix stack ORC unwind from kprobe_multi return probe 2025-11-06T01:05:19+00:00 Jiri Olsa jolsa@kernel.org 2025-11-04T21:54:03+00:00 20a0bc10272fa17a44fc857c31574a8306f60d20 Currently we don't get stack trace via ORC unwinder on top of fgraph exit handler. We can see that when generating stacktrace from kretprobe_multi bpf program which is based on fprobe/fgraph. The reason is that the ORC unwind code won't get pass the return_to_handler callback installed by fgraph return probe machinery. Solving this by creating stack frame in return_to_handler expected by ftrace_graph_ret_addr function to recover original return address and continue with the unwind. Also updating the pt_regs data with cs/flags/rsp which are needed for successful stack retrieval from ebpf bpf_get_stackid helper. - in get_perf_callchain we check user_mode(regs) so CS has to be set - in perf_callchain_kernel we call perf_hw_regs(regs), so EFLAGS/FIXED has to be unset Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20251104215405.168643-3-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> 
Currently we don't get stack trace via ORC unwinder on top of fgraph exit
handler. We can see that when generating stacktrace from kretprobe_multi
bpf program which is based on fprobe/fgraph.

The reason is that the ORC unwind code won't get pass the return_to_handler
callback installed by fgraph return probe machinery.

Solving this by creating stack frame in return_to_handler expected by
ftrace_graph_ret_addr function to recover original return address and
continue with the unwind.

Also updating the pt_regs data with cs/flags/rsp which are needed for
successful stack retrieval from ebpf bpf_get_stackid helper.
 - in get_perf_callchain we check user_mode(regs) so CS has to be set
 - in perf_callchain_kernel we call perf_hw_regs(regs), so EFLAGS/FIXED
    has to be unset

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251104215405.168643-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
x86: uaccess: don't use runtime-const rewriting in modules 2025-11-05T01:24:36+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-11-04T06:25:20+00:00 284922f4c563aa3a8558a00f2a05722133237fe8 The runtime-const infrastructure was never designed to handle the modular case, because the constant fixup is only done at boot time for core kernel code. But by the time I used it for the x86-64 user space limit handling in commit 86e6b1547b3d ("x86: fix user address masking non-canonical speculation issue"), I had completely repressed that fact. And it all happens to work because the only code that currently actually gets inlined by modules is for the access_ok() limit check, where the default constant value works even when not fixed up. Because at least I had intentionally made it be something that is in the non-canonical address space region. But it's technically very wrong, and it does mean that at least in theory, the use of 'access_ok()' + '__get_user()' can trigger the same speculation issue with non-canonical addresses that the original commit was all about. The pattern is unusual enough that this probably doesn't matter in practice, but very wrong is still very wrong. Also, let's fix it before the nice optimized scoped user accessor helpers that Thomas Gleixner is working on cause this pseudo-constant to then be more widely used. This all came up due to an unrelated discussion with Mateusz Guzik about using the runtime const infrastructure for names_cachep accesses too. There the modular case was much more obviously broken, and Mateusz noted it in his 'v2' of the patch series. That then made me notice how broken 'access_ok()' had been in modules all along. Mea culpa, mea maxima culpa. Fix it by simply not using the runtime-const code in modules, and just using the USER_PTR_MAX variable value instead. This is not performance-critical like the core user accessor functions (get_user() and friends) are. Also make sure this doesn't get forgotten the next time somebody wants to do runtime constant optimizations by having the x86 runtime-const.h header file error out if included by modules. Fixes: 86e6b1547b3d ("x86: fix user address masking non-canonical speculation issue") Acked-by: Borislav Petkov <bp@alien8.de> Acked-by: Sean Christopherson <seanjc@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Triggered-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/all/20251030105242.801528-1-mjguzik@gmail.com/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The runtime-const infrastructure was never designed to handle the
modular case, because the constant fixup is only done at boot time for
core kernel code.

But by the time I used it for the x86-64 user space limit handling in
commit 86e6b1547b3d ("x86: fix user address masking non-canonical
speculation issue"), I had completely repressed that fact.

And it all happens to work because the only code that currently actually
gets inlined by modules is for the access_ok() limit check, where the
default constant value works even when not fixed up.  Because at least I
had intentionally made it be something that is in the non-canonical
address space region.

But it's technically very wrong, and it does mean that at least in
theory, the use of 'access_ok()' + '__get_user()' can trigger the same
speculation issue with non-canonical addresses that the original commit
was all about.

The pattern is unusual enough that this probably doesn't matter in
practice, but very wrong is still very wrong.  Also, let's fix it before
the nice optimized scoped user accessor helpers that Thomas Gleixner is
working on cause this pseudo-constant to then be more widely used.

This all came up due to an unrelated discussion with Mateusz Guzik about
using the runtime const infrastructure for names_cachep accesses too.
There the modular case was much more obviously broken, and Mateusz noted
it in his 'v2' of the patch series.

That then made me notice how broken 'access_ok()' had been in modules
all along.  Mea culpa, mea maxima culpa.

Fix it by simply not using the runtime-const code in modules, and just
using the USER_PTR_MAX variable value instead.  This is not
performance-critical like the core user accessor functions (get_user()
and friends) are.

Also make sure this doesn't get forgotten the next time somebody wants
to do runtime constant optimizations by having the x86 runtime-const.h
header file error out if included by modules.

Fixes: 86e6b1547b3d ("x86: fix user address masking non-canonical speculation issue")
Acked-by: Borislav Petkov <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Triggered-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/all/20251030105242.801528-1-mjguzik@gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
x86/amd_node: Fix AMD root device caching 2025-11-03T11:46:57+00:00 Yazen Ghannam yazen.ghannam@amd.com 2025-10-28T21:35:42+00:00 0a4b61d9c2e496b5f0a10e29e355a1465c8738bb Recent AMD node rework removed the "search and count" method of caching AMD root devices. This depended on the value from a Data Fabric register that was expected to hold the PCI bus of one of the root devices attached to that fabric. However, this expectation is incorrect. The register, when read from PCI config space, returns the bitwise-OR of the buses of all attached root devices. This behavior is benign on AMD reference design boards, since the bus numbers are aligned. This results in a bitwise-OR value matching one of the buses. For example, 0x00 | 0x40 | 0xA0 | 0xE0 = 0xE0. This behavior breaks on boards where the bus numbers are not exactly aligned. For example, 0x00 | 0x07 | 0xE0 | 0x15 = 0x1F. The examples above are for AMD node 0. The first root device on other nodes will not be 0x00. The first root device for other nodes will depend on the total number of root devices, the system topology, and the specific PCI bus number assignment. For example, a system with 2 AMD nodes could have this: Node 0 : 0x00 0x07 0x0e 0x15 Node 1 : 0x1c 0x23 0x2a 0x31 The bus numbering style in the reference boards is not a requirement. The numbering found in other boards is not incorrect. Therefore, the root device caching method needs to be adjusted. Go back to the "search and count" method used before the recent rework. Search for root devices using PCI class code rather than fixed PCI IDs. This keeps the goal of the rework (remove dependency on PCI IDs) while being able to support various board designs. Merge helper functions to reduce code duplication. [ bp: Reflow comment. ] Fixes: 40a5f6ffdfc8 ("x86/amd_nb: Simplify root device search") Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/all/20251028-fix-amd-root-v2-1-843e38f8be2c@amd.com 
Recent AMD node rework removed the "search and count" method of caching AMD
root devices. This depended on the value from a Data Fabric register that was
expected to hold the PCI bus of one of the root devices attached to that
fabric.

However, this expectation is incorrect. The register, when read from PCI
config space, returns the bitwise-OR of the buses of all attached root
devices.

This behavior is benign on AMD reference design boards, since the bus numbers
are aligned. This results in a bitwise-OR value matching one of the buses. For
example, 0x00 | 0x40 | 0xA0 | 0xE0 = 0xE0.

This behavior breaks on boards where the bus numbers are not exactly aligned.
For example, 0x00 | 0x07 | 0xE0 | 0x15 = 0x1F.

The examples above are for AMD node 0. The first root device on other nodes
will not be 0x00. The first root device for other nodes will depend on the
total number of root devices, the system topology, and the specific PCI bus
number assignment.

For example, a system with 2 AMD nodes could have this:

  Node 0 : 0x00 0x07 0x0e 0x15
  Node 1 : 0x1c 0x23 0x2a 0x31

The bus numbering style in the reference boards is not a requirement.  The
numbering found in other boards is not incorrect. Therefore, the root device
caching method needs to be adjusted.

Go back to the "search and count" method used before the recent rework.
Search for root devices using PCI class code rather than fixed PCI IDs.

This keeps the goal of the rework (remove dependency on PCI IDs) while being
able to support various board designs.

Merge helper functions to reduce code duplication.

  [ bp: Reflow comment. ]

Fixes: 40a5f6ffdfc8 ("x86/amd_nb: Simplify root device search")
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/all/20251028-fix-amd-root-v2-1-843e38f8be2c@amd.com
x86/mm: Ensure clear_page() variants always have __kcfi_typeid_ symbols 2025-10-31T21:47:24+00:00 Nathan Chancellor nathan@kernel.org 2025-10-13T21:27:36+00:00 9b041a4b66b3b62c30251e700b5688324cf66625 When building with CONFIG_CFI=y and CONFIG_LTO_CLANG_FULL=y, there is a series of errors from the various versions of clear_page() not having __kcfi_typeid_ symbols. $ cat kernel/configs/repro.config CONFIG_CFI=y # CONFIG_LTO_NONE is not set CONFIG_LTO_CLANG_FULL=y $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean defconfig repro.config bzImage ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_rep >>> referenced by ld-temp.o >>> vmlinux.o:(__cfi_clear_page_rep) ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_orig >>> referenced by ld-temp.o >>> vmlinux.o:(__cfi_clear_page_orig) ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_erms >>> referenced by ld-temp.o >>> vmlinux.o:(__cfi_clear_page_erms) With full LTO, it is possible for LLVM to realize that these functions never have their address taken (as they are only used within an alternative, which will make them a direct call) across the whole kernel and either drop or skip generating their kCFI type identification symbols. clear_page_{rep,orig,erms}() are defined in clear_page_64.S with SYM_TYPED_FUNC_START as a result of 2981557cb040 ("x86,kcfi: Fix EXPORT_SYMBOL vs kCFI"), as exported functions are free to be called indirectly thus need kCFI type identifiers. Use KCFI_REFERENCE with these clear_page() functions to force LLVM to see these functions as address-taken and generate then keep the kCFI type identifiers. Fixes: 2981557cb040 ("x86,kcfi: Fix EXPORT_SYMBOL vs kCFI") Closes: https://github.com/ClangBuiltLinux/linux/issues/2128 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://patch.msgid.link/20251013-x86-fix-clear_page-cfi-full-lto-errors-v1-1-d69534c0be61@kernel.org 
When building with CONFIG_CFI=y and CONFIG_LTO_CLANG_FULL=y, there is a series
of errors from the various versions of clear_page() not having __kcfi_typeid_
symbols.

  $ cat kernel/configs/repro.config
  CONFIG_CFI=y
  # CONFIG_LTO_NONE is not set
  CONFIG_LTO_CLANG_FULL=y

  $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean defconfig repro.config bzImage
  ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_rep
  >>> referenced by ld-temp.o
  >>>               vmlinux.o:(__cfi_clear_page_rep)

  ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_orig
  >>> referenced by ld-temp.o
  >>>               vmlinux.o:(__cfi_clear_page_orig)

  ld.lld: error: undefined symbol: __kcfi_typeid_clear_page_erms
  >>> referenced by ld-temp.o
  >>>               vmlinux.o:(__cfi_clear_page_erms)

With full LTO, it is possible for LLVM to realize that these functions never
have their address taken (as they are only used within an alternative, which
will make them a direct call) across the whole kernel and either drop or skip
generating their kCFI type identification symbols.

clear_page_{rep,orig,erms}() are defined in clear_page_64.S with
SYM_TYPED_FUNC_START as a result of

  2981557cb040 ("x86,kcfi: Fix EXPORT_SYMBOL vs kCFI"),

as exported functions are free to be called indirectly thus need kCFI type
identifiers.

Use KCFI_REFERENCE with these clear_page() functions to force LLVM to see
these functions as address-taken and generate then keep the kCFI type
identifiers.

Fixes: 2981557cb040 ("x86,kcfi: Fix EXPORT_SYMBOL vs kCFI")
Closes: https://github.com/ClangBuiltLinux/linux/issues/2128
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://patch.msgid.link/20251013-x86-fix-clear_page-cfi-full-lto-errors-v1-1-d69534c0be61@kernel.org
x86/cpu: Add/fix core comments for {Panther,Nova} Lake 2025-10-30T10:34:02+00:00 Tony Luck tony.luck@intel.com 2025-10-28T17:29:48+00:00 89216c9051ef6635f1514f8e0d2f9cd63b37a3b6 The E-core in Panther Lake is Darkmont, not Crestmont. Nova Lake is built from Coyote Cove (P-core) and Arctic Wolf (E-core). Fixes: 43bb700cff6b ("x86/cpu: Update Intel Family comments") Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://patch.msgid.link/20251028172948.6721-1-tony.luck@intel.com 
The E-core in Panther Lake is Darkmont, not Crestmont.

Nova Lake is built from Coyote Cove (P-core) and Arctic Wolf (E-core).

Fixes: 43bb700cff6b ("x86/cpu: Update Intel Family comments")
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20251028172948.6721-1-tony.luck@intel.com
Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2025-10-11T18:19:16+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-10-11T18:19:16+00:00 9591fdb0611dccdeeeeacb99d89f0098737d209b Pull more x86 updates from Borislav Petkov: - Remove a bunch of asm implementing condition flags testing in KVM's emulator in favor of int3_emulate_jcc() which is written in C - Replace KVM fastops with C-based stubs which avoids problems with the fastop infra related to latter not adhering to the C ABI due to their special calling convention and, more importantly, bypassing compiler control-flow integrity checking because they're written in asm - Remove wrongly used static branches and other ugliness accumulated over time in hyperv's hypercall implementation with a proper static function call to the correct hypervisor call variant - Add some fixes and modifications to allow running FRED-enabled kernels in KVM even on non-FRED hardware - Add kCFI improvements like validating indirect calls and prepare for enabling kCFI with GCC. Add cmdline params documentation and other code cleanups - Use the single-byte 0xd6 insn as the official #UD single-byte undefined opcode instruction as agreed upon by both x86 vendors - Other smaller cleanups and touchups all over the place * tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86,retpoline: Optimize patch_retpoline() x86,ibt: Use UDB instead of 0xEA x86/cfi: Remove __noinitretpoline and __noretpoline x86/cfi: Add "debug" option to "cfi=" bootparam x86/cfi: Standardize on common "CFI:" prefix for CFI reports x86/cfi: Document the "cfi=" bootparam options x86/traps: Clarify KCFI instruction layout compiler_types.h: Move __nocfi out of compiler-specific header objtool: Validate kCFI calls x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware x86/fred: Install system vector handlers even if FRED isn't fully enabled x86/hyperv: Use direct call to hypercall-page x86/hyperv: Clean up hv_do_hypercall() KVM: x86: Remove fastops KVM: x86: Convert em_salc() to C KVM: x86: Introduce EM_ASM_3WCL KVM: x86: Introduce EM_ASM_1SRC2 KVM: x86: Introduce EM_ASM_2CL KVM: x86: Introduce EM_ASM_2W ... 
Pull more x86 updates from Borislav Petkov:

 - Remove a bunch of asm implementing condition flags testing in KVM's
   emulator in favor of int3_emulate_jcc() which is written in C

 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm

 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant

 - Add some fixes and modifications to allow running FRED-enabled
   kernels in KVM even on non-FRED hardware

 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups

 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors

 - Other smaller cleanups and touchups all over the place

* tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86,retpoline: Optimize patch_retpoline()
  x86,ibt: Use UDB instead of 0xEA
  x86/cfi: Remove __noinitretpoline and __noretpoline
  x86/cfi: Add "debug" option to "cfi=" bootparam
  x86/cfi: Standardize on common "CFI:" prefix for CFI reports
  x86/cfi: Document the "cfi=" bootparam options
  x86/traps: Clarify KCFI instruction layout
  compiler_types.h: Move __nocfi out of compiler-specific header
  objtool: Validate kCFI calls
  x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y
  x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware
  x86/fred: Install system vector handlers even if FRED isn't fully enabled
  x86/hyperv: Use direct call to hypercall-page
  x86/hyperv: Clean up hv_do_hypercall()
  KVM: x86: Remove fastops
  KVM: x86: Convert em_salc() to C
  KVM: x86: Introduce EM_ASM_3WCL
  KVM: x86: Introduce EM_ASM_1SRC2
  KVM: x86: Introduce EM_ASM_2CL
  KVM: x86: Introduce EM_ASM_2W
  ...
Merge tag 'x86_cleanups_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2025-10-11T17:51:14+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-10-11T17:51:14+00:00 2f0a7504530c24f55daec7d2364d933bb1a1fa68 Pull x86 cleanups from Borislav Petkov: - Simplify inline asm flag output operands now that the minimum compiler version supports the =@ccCOND syntax - Remove a bunch of AS_* Kconfig symbols which detect assembler support for various instruction mnemonics now that the minimum assembler version supports them all - The usual cleanups all over the place * tag 'x86_cleanups_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ x86/sgx: Use ENCLS mnemonic in <kernel/cpu/sgx/encls.h> x86/mtrr: Remove license boilerplate text with bad FSF address x86/asm: Use RDPKRU and WRPKRU mnemonics in <asm/special_insns.h> x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h> x86/entry/fred: Push __KERNEL_CS directly x86/kconfig: Remove CONFIG_AS_AVX512 crypto: x86 - Remove CONFIG_AS_VPCLMULQDQ crypto: X86 - Remove CONFIG_AS_VAES crypto: x86 - Remove CONFIG_AS_GFNI x86/kconfig: Drop unused and needless config X86_64_SMP 
Pull x86 cleanups from Borislav Petkov:

 - Simplify inline asm flag output operands now that the minimum
   compiler version supports the =@ccCOND syntax

 - Remove a bunch of AS_* Kconfig symbols which detect assembler support
   for various instruction mnemonics now that the minimum assembler
   version supports them all

 - The usual cleanups all over the place

* tag 'x86_cleanups_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__
  x86/sgx: Use ENCLS mnemonic in <kernel/cpu/sgx/encls.h>
  x86/mtrr: Remove license boilerplate text with bad FSF address
  x86/asm: Use RDPKRU and WRPKRU mnemonics in <asm/special_insns.h>
  x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h>
  x86/entry/fred: Push __KERNEL_CS directly
  x86/kconfig: Remove CONFIG_AS_AVX512
  crypto: x86 - Remove CONFIG_AS_VPCLMULQDQ
  crypto: X86 - Remove CONFIG_AS_VAES
  crypto: x86 - Remove CONFIG_AS_GFNI
  x86/kconfig: Drop unused and needless config X86_64_SMP
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2025-10-06T19:37:34+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-10-06T19:37:34+00:00 256e3417065b2721f77bcd37331796b59483ef3b Pull x86 kvm updates from Paolo Bonzini: "Generic: - Rework almost all of KVM's exports to expose symbols only to KVM's x86 vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko x86: - Rework almost all of KVM x86's exports to expose symbols only to KVM's vendor modules, i.e. to kvm-{amd,intel}.ko - Add support for virtualizing Control-flow Enforcement Technology (CET) on Intel (Shadow Stacks and Indirect Branch Tracking) and AMD (Shadow Stacks). It is worth noting that while SHSTK and IBT can be enabled separately in CPUID, it is not really possible to virtualize them separately. Therefore, Intel processors will really allow both SHSTK and IBT under the hood if either is made visible in the guest's CPUID. The alternative would be to intercept XSAVES/XRSTORS, which is not feasible for performance reasons - Fix a variety of fuzzing WARNs all caused by checking L1 intercepts when completing userspace I/O. KVM has already committed to allowing L2 to to perform I/O at that point - Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the MSR is supposed to exist for v2 PMUs - Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs - Add support for the immediate forms of RDMSR and WRMSRNS, sans full emulator support (KVM should never need to emulate the MSRs outside of forced emulation and other contrived testing scenarios) - Clean up the MSR APIs in preparation for CET and FRED virtualization, as well as mediated vPMU support - Clean up a pile of PMU code in anticipation of adding support for mediated vPMUs - Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI vmexits needed to faithfully emulate an I/O APIC for such guests - Many cleanups and minor fixes - Recover possible NX huge pages within the TDP MMU under read lock to reduce guest jitter when restoring NX huge pages - Return -EAGAIN during prefault if userspace concurrently deletes/moves the relevant memslot, to fix an issue where prefaulting could deadlock with the memslot update x86 (AMD): - Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is supported - Require a minimum GHCB version of 2 when starting SEV-SNP guests via KVM_SEV_INIT2 so that invalid GHCB versions result in immediate errors instead of latent guest failures - Add support for SEV-SNP's CipherText Hiding, an opt-in feature that prevents unauthorized CPU accesses from reading the ciphertext of SNP guest private memory, e.g. to attempt an offline attack. This feature splits the shared SEV-ES/SEV-SNP ASID space into separate ranges for SEV-ES and SEV-SNP guests, therefore a new module parameter is needed to control the number of ASIDs that can be used for VMs with CipherText Hiding vs. how many can be used to run SEV-ES guests - Add support for Secure TSC for SEV-SNP guests, which prevents the untrusted host from tampering with the guest's TSC frequency, while still allowing the the VMM to configure the guest's TSC frequency prior to launch - Validate the XCR0 provided by the guest (via the GHCB) to avoid bugs resulting from bogus XCR0 values - Save an SEV guest's policy if and only if LAUNCH_START fully succeeds to avoid leaving behind stale state (thankfully not consumed in KVM) - Explicitly reject non-positive effective lengths during SNP's LAUNCH_UPDATE instead of subtly relying on guest_memfd to deal with them - Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the host's desired TSC_AUX, to fix a bug where KVM was keeping a different vCPU's TSC_AUX in the host MSR until return to userspace KVM (Intel): - Preparation for FRED support - Don't retry in TDX's anti-zero-step mitigation if the target memslot is invalid, i.e. is being deleted or moved, to fix a deadlock scenario similar to the aforementioned prefaulting case - Misc bugfixes and minor cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits) KVM: x86: Export KVM-internal symbols for sub-modules only KVM: x86: Drop pointless exports of kvm_arch_xxx() hooks KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c KVM: Export KVM-internal symbols for sub-modules only KVM: s390/vfio-ap: Use kvm_is_gpa_in_memslot() instead of open coded equivalent KVM: VMX: Make CR4.CET a guest owned bit KVM: selftests: Verify MSRs are (not) in save/restore list when (un)supported KVM: selftests: Add coverage for KVM-defined registers in MSRs test KVM: selftests: Add KVM_{G,S}ET_ONE_REG coverage to MSRs test KVM: selftests: Extend MSRs test to validate vCPUs without supported features KVM: selftests: Add support for MSR_IA32_{S,U}_CET to MSRs test KVM: selftests: Add an MSR test to exercise guest/host and read/write KVM: x86: Define AMD's #HV, #VC, and #SX exception vectors KVM: x86: Define Control Protection Exception (#CP) vector KVM: x86: Add human friendly formatting for #XM, and #VE KVM: SVM: Enable shadow stack virtualization for SVM KVM: SEV: Synchronize MSR_IA32_XSS from the GHCB when it's valid KVM: SVM: Pass through shadow stack MSRs as appropriate KVM: SVM: Update dump_vmcb with shadow stack save area additions KVM: nSVM: Save/load CET Shadow Stack state to/from vmcb12/vmcb02 ... 
Pull x86 kvm updates from Paolo Bonzini:
 "Generic:

   - Rework almost all of KVM's exports to expose symbols only to KVM's
     x86 vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko

  x86:

   - Rework almost all of KVM x86's exports to expose symbols only to
     KVM's vendor modules, i.e. to kvm-{amd,intel}.ko

   - Add support for virtualizing Control-flow Enforcement Technology
     (CET) on Intel (Shadow Stacks and Indirect Branch Tracking) and AMD
     (Shadow Stacks).

     It is worth noting that while SHSTK and IBT can be enabled
     separately in CPUID, it is not really possible to virtualize them
     separately. Therefore, Intel processors will really allow both
     SHSTK and IBT under the hood if either is made visible in the
     guest's CPUID. The alternative would be to intercept
     XSAVES/XRSTORS, which is not feasible for performance reasons

   - Fix a variety of fuzzing WARNs all caused by checking L1 intercepts
     when completing userspace I/O. KVM has already committed to
     allowing L2 to to perform I/O at that point

   - Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the
     MSR is supposed to exist for v2 PMUs

   - Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs

   - Add support for the immediate forms of RDMSR and WRMSRNS, sans full
     emulator support (KVM should never need to emulate the MSRs outside
     of forced emulation and other contrived testing scenarios)

   - Clean up the MSR APIs in preparation for CET and FRED
     virtualization, as well as mediated vPMU support

   - Clean up a pile of PMU code in anticipation of adding support for
     mediated vPMUs

   - Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI
     vmexits needed to faithfully emulate an I/O APIC for such guests

   - Many cleanups and minor fixes

   - Recover possible NX huge pages within the TDP MMU under read lock
     to reduce guest jitter when restoring NX huge pages

   - Return -EAGAIN during prefault if userspace concurrently
     deletes/moves the relevant memslot, to fix an issue where
     prefaulting could deadlock with the memslot update

  x86 (AMD):

   - Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is
     supported

   - Require a minimum GHCB version of 2 when starting SEV-SNP guests
     via KVM_SEV_INIT2 so that invalid GHCB versions result in immediate
     errors instead of latent guest failures

   - Add support for SEV-SNP's CipherText Hiding, an opt-in feature that
     prevents unauthorized CPU accesses from reading the ciphertext of
     SNP guest private memory, e.g. to attempt an offline attack. This
     feature splits the shared SEV-ES/SEV-SNP ASID space into separate
     ranges for SEV-ES and SEV-SNP guests, therefore a new module
     parameter is needed to control the number of ASIDs that can be used
     for VMs with CipherText Hiding vs. how many can be used to run
     SEV-ES guests

   - Add support for Secure TSC for SEV-SNP guests, which prevents the
     untrusted host from tampering with the guest's TSC frequency, while
     still allowing the the VMM to configure the guest's TSC frequency
     prior to launch

   - Validate the XCR0 provided by the guest (via the GHCB) to avoid
     bugs resulting from bogus XCR0 values

   - Save an SEV guest's policy if and only if LAUNCH_START fully
     succeeds to avoid leaving behind stale state (thankfully not
     consumed in KVM)

   - Explicitly reject non-positive effective lengths during SNP's
     LAUNCH_UPDATE instead of subtly relying on guest_memfd to deal with
     them

   - Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the
     host's desired TSC_AUX, to fix a bug where KVM was keeping a
     different vCPU's TSC_AUX in the host MSR until return to userspace

  KVM (Intel):

   - Preparation for FRED support

   - Don't retry in TDX's anti-zero-step mitigation if the target
     memslot is invalid, i.e. is being deleted or moved, to fix a
     deadlock scenario similar to the aforementioned prefaulting case

   - Misc bugfixes and minor cleanups"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
  KVM: x86: Export KVM-internal symbols for sub-modules only
  KVM: x86: Drop pointless exports of kvm_arch_xxx() hooks
  KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c
  KVM: Export KVM-internal symbols for sub-modules only
  KVM: s390/vfio-ap: Use kvm_is_gpa_in_memslot() instead of open coded equivalent
  KVM: VMX: Make CR4.CET a guest owned bit
  KVM: selftests: Verify MSRs are (not) in save/restore list when (un)supported
  KVM: selftests: Add coverage for KVM-defined registers in MSRs test
  KVM: selftests: Add KVM_{G,S}ET_ONE_REG coverage to MSRs test
  KVM: selftests: Extend MSRs test to validate vCPUs without supported features
  KVM: selftests: Add support for MSR_IA32_{S,U}_CET to MSRs test
  KVM: selftests: Add an MSR test to exercise guest/host and read/write
  KVM: x86: Define AMD's #HV, #VC, and #SX exception vectors
  KVM: x86: Define Control Protection Exception (#CP) vector
  KVM: x86: Add human friendly formatting for #XM, and #VE
  KVM: SVM: Enable shadow stack virtualization for SVM
  KVM: SEV: Synchronize MSR_IA32_XSS from the GHCB when it's valid
  KVM: SVM: Pass through shadow stack MSRs as appropriate
  KVM: SVM: Update dump_vmcb with shadow stack save area additions
  KVM: nSVM: Save/load CET Shadow Stack state to/from vmcb12/vmcb02
  ...