linux-stable.git/arch/x86/kernel/process_64.c, branch linux-rolling-stable

x86: Restrict KVM-induced symbol exports to KVM modules where obvious/possible

2025-11-12T23:29:38+00:00

Extend KVM's export macro framework to provide EXPORT_SYMBOL_FOR_KVM(),
and use the helper macro to export symbols for KVM throughout x86 if and
only if KVM will build one or more modules, and only for those modules.

To avoid unnecessary exports when CONFIG_KVM=m but kvm.ko will not be
built (because no vendor modules are selected), let arch code #define
EXPORT_SYMBOL_FOR_KVM to suppress/override the exports.

Note, the set of symbols to restrict to KVM was generated by manual search
and audit; any "misses" are due to human error, not some grand plan.

Signed-off-by: Sean Christopherson 
Signed-off-by: Dave Hansen 
Acked-by: Kai Huang 
Tested-by: Kai Huang 
Link: https://patch.msgid.link/20251112173944.1380633-5-seanjc%40google.com

x86/process: Clear hardware feedback history for AMD processors

2025-07-07T20:30:36+00:00

Incorporate a mechanism within the context switching code to reset the
hardware history for AMD processors. Specifically, when a task is switched in,
the class ID is read and the hardware workload classification history of the
CPU firmware is reset. Then, the workload classification for the next running
thread is begun.

  [ bp: Massage commit message. ]

Signed-off-by: Perry Yuan 
Co-developed-by: Mario Limonciello 
Signed-off-by: Mario Limonciello 
Signed-off-by: Borislav Petkov (AMD) 
Acked-by: Ilpo Järvinen 
Link: https://lore.kernel.org/20250609200518.3616080-10-superm1@kernel.org

x86/traps: Initialize DR7 by writing its architectural reset value

2025-06-24T20:15:52+00:00

Initialize DR7 by writing its architectural reset value to always set
bit 10, which is reserved to '1', when "clearing" DR7 so as not to
trigger unanticipated behavior if said bit is ever unreserved, e.g. as
a feature enabling flag with inverted polarity.

Signed-off-by: Xin Li (Intel) 
Signed-off-by: Dave Hansen 
Reviewed-by: H. Peter Anvin (Intel) 
Reviewed-by: Sohil Mehta 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Sean Christopherson 
Tested-by: Sohil Mehta 
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250620231504.2676902-3-xin%40zytor.com

Merge tag 'x86_cache_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-05-27T16:53:02+00:00

Pull x86 resource control updates from Borislav Petkov:
 "Carve out the resctrl filesystem-related code into fs/resctrl/ so that
  multiple architectures can share the fs API for manipulating their
  respective hw resource control implementation.

  This is the second step in the work towards sharing the resctrl
  filesystem interface, the next one being plugging ARM's MPAM into the
  aforementioned fs API"

* tag 'x86_cache_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  MAINTAINERS: Add reviewers for fs/resctrl
  x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl
  x86/resctrl: Always initialise rid field in rdt_resources_all[]
  x86/resctrl: Relax some asm #includes
  x86/resctrl: Prefer alloc(sizeof(*foo)) idiom in rdt_init_fs_context()
  x86/resctrl: Squelch whitespace anomalies in resctrl core code
  x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h
  x86/resctrl: Fix types in resctrl_arch_mon_ctx_{alloc,free}() stubs
  x86/resctrl: Move enum resctrl_event_id to resctrl.h
  x86/resctrl: Move the filesystem bits to headers visible to fs/resctrl
  fs/resctrl: Add boiler plate for external resctrl code
  x86/resctrl: Add 'resctrl' to the title of the resctrl documentation
  x86/resctrl: Split trace.h
  x86/resctrl: Expand the width of domid by replacing mon_data_bits
  x86/resctrl: Add end-marker to the resctrl_event_id enum
  x86/resctrl: Move is_mba_sc() out of core.c
  x86/resctrl: Drop __init/__exit on assorted symbols
  x86/resctrl: Resctrl_exit() teardown resctrl but leave the mount point
  x86/resctrl: Check all domains are offline in resctrl_exit()
  x86/resctrl: Rename resctrl_sched_in() to begin with "resctrl_arch_"
  ...

x86/resctrl: Rename resctrl_sched_in() to begin with "resctrl_arch_"

2025-05-15T19:01:00+00:00

resctrl_sched_in() loads the architecture specific CPU MSRs with the
CLOSID and RMID values. This function was named before resctrl was
split to have architecture specific code, and generic filesystem code.

This function is obviously architecture specific, but does not begin
with 'resctrl_arch_', making it the odd one out in the functions an
architecture needs to support to enable resctrl.

Rename it for consistency. This is purely cosmetic.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-7-james.morse@arm.com

Merge branch 'x86/msr' into x86/core, to resolve conflicts

2025-05-13T08:42:06+00:00

 Conflicts:
	arch/x86/boot/startup/sme.c
	arch/x86/coco/sev/core.c
	arch/x86/kernel/fpu/core.c
	arch/x86/kernel/fpu/xstate.c

 Semantic conflict:
	arch/x86/include/asm/sev-internal.h

Signed-off-by: Ingo Molnar

x86/fpu: Simplify the switch_fpu_prepare() + switch_fpu_finish() logic

2025-05-04T08:29:24+00:00

Now that switch_fpu_finish() doesn't load the FPU state, it makes more
sense to fold it into switch_fpu_prepare() renamed to switch_fpu(), and
more importantly, use the "prev_p" task as a target for TIF_NEED_FPU_LOAD.
It doesn't make any sense to delay set_tsk_thread_flag(TIF_NEED_FPU_LOAD)
until "prev_p" is scheduled again.

There is no worry about the very first context switch, fpu_clone() must
always set TIF_NEED_FPU_LOAD.

Also, shift the test_tsk_thread_flag(TIF_NEED_FPU_LOAD) from the callers
to switch_fpu().

Note that the "PF_KTHREAD | PF_USER_WORKER" check can be removed but
this deserves a separate patch which can change more functions, say,
kernel_fpu_begin_mask().

Signed-off-by: Oleg Nesterov 
Signed-off-by: Ingo Molnar 
Cc: Chang S . Bae 
Cc: H. Peter Anvin 
Cc: Andy Lutomirski 
Cc: Brian Gerst 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20250503143830.GA8982@redhat.com

x86/msr: Add explicit includes of

2025-05-02T08:23:47+00:00

For historic reasons there are some TSC-related functions in the
 header, even though there's an  header.

To facilitate the relocation of rdtsc{,_ordered}() from 
to  and to eventually eliminate the inclusion of
 in , add an explicit  dependency
to the source files that reference definitions from .

[ mingo: Clarified the changelog. ]

Signed-off-by: Xin Li (Intel) 
Signed-off-by: Ingo Molnar 
Acked-by: Dave Hansen 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Ilpo Järvinen 
Cc: Andy Lutomirski 
Cc: Brian Gerst 
Cc: Juergen Gross 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Kees Cook 
Cc: Peter Zijlstra 
Cc: Borislav Petkov 
Cc: Thomas Gleixner 
Cc: Josh Poimboeuf 
Cc: Uros Bizjak 
Link: https://lore.kernel.org/r/20250501054241.1245648-1-xin@zytor.com

x86/msr: Rename 'wrmsrl()' to 'wrmsrq()'

2025-04-10T09:58:33+00:00

Suggested-by: "H. Peter Anvin" 
Signed-off-by: Ingo Molnar 
Acked-by: Peter Zijlstra (Intel) 
Cc: Juergen Gross 
Cc: Dave Hansen 
Cc: Xin Li 
Cc: Linus Torvalds

x86/msr: Rename 'rdmsrl()' to 'rdmsrq()'

2025-04-10T09:58:27+00:00

Suggested-by: "H. Peter Anvin" 
Signed-off-by: Ingo Molnar 
Acked-by: Peter Zijlstra (Intel) 
Cc: Juergen Gross 
Cc: Dave Hansen 
Cc: Xin Li 
Cc: Linus Torvalds