tjh.dev
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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Pull KVM fixes from Paolo Bonzini:
"ARM:
- Avoid use of uninitialized memcache pointer in user_mem_abort()
- Always set HCR_EL2.xMO bits when running in VHE, allowing
interrupts to be taken while TGE=0 and fixing an ugly bug on
AmpereOne that occurs when taking an interrupt while clearing the
xMO bits (AC03_CPU_36)
- Prevent VMMs from hiding support for AArch64 at any EL virtualized
by KVM
- Save/restore the host value for HCRX_EL2 instead of restoring an
incorrect fixed value
- Make host_stage2_set_owner_locked() check that the entire requested
range is memory rather than just the first page
RISC-V:
- Add missing reset of smstateen CSRs
x86:
- Forcibly leave SMM on SHUTDOWN interception on AMD CPUs to avoid
causing problems due to KVM stuffing INIT on SHUTDOWN (KVM needs to
sanitize the VMCB as its state is undefined after SHUTDOWN,
emulating INIT is the least awful choice).
- Track the valid sync/dirty fields in kvm_run as a u64 to ensure KVM
KVM doesn't goof a sanity check in the future.
- Free obsolete roots when (re)loading the MMU to fix a bug where
pre-faulting memory can get stuck due to always encountering a
stale root.
- When dumping GHCB state, use KVM's snapshot instead of the raw GHCB
page to print state, so that KVM doesn't print stale/wrong
information.
- When changing memory attributes (e.g. shared <=> private), add
potential hugepage ranges to the mmu_invalidate_range_{start,end}
set so that KVM doesn't create a shared/private hugepage when the
the corresponding attributes will become mixed (the attributes are
commited *after* KVM finishes the invalidation).
- Rework the SRSO mitigation to enable BP_SPEC_REDUCE only when KVM
has at least one active VM. Effectively BP_SPEC_REDUCE when KVM is
loaded led to very measurable performance regressions for non-KVM
workloads"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: SVM: Set/clear SRSO's BP_SPEC_REDUCE on 0 <=> 1 VM count transitions
KVM: arm64: Fix memory check in host_stage2_set_owner_locked()
KVM: arm64: Kill HCRX_HOST_FLAGS
KVM: arm64: Properly save/restore HCRX_EL2
KVM: arm64: selftest: Don't try to disable AArch64 support
KVM: arm64: Prevent userspace from disabling AArch64 support at any virtualisable EL
KVM: arm64: Force HCR_EL2.xMO to 1 at all times in VHE mode
KVM: arm64: Fix uninitialized memcache pointer in user_mem_abort()
KVM: x86/mmu: Prevent installing hugepages when mem attributes are changing
KVM: SVM: Update dump_ghcb() to use the GHCB snapshot fields
KVM: RISC-V: reset smstateen CSRs
KVM: x86/mmu: Check and free obsolete roots in kvm_mmu_reload()
KVM: x86: Check that the high 32bits are clear in kvm_arch_vcpu_ioctl_run()
KVM: SVM: Forcibly leave SMM mode on SHUTDOWN interception
Pull MIPS fixes from Thomas Bogendoerfer:
- Fix delayed timers
- Fix NULL pointer deref
- Fix wrong range check
* tag 'mips-fixes_6.15_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: Fix MAX_REG_OFFSET
MIPS: CPS: Fix potential NULL pointer dereferences in cps_prepare_cpus()
MIPS: rename rollback_handler with skipover_handler
MIPS: Move r4k_wait() to .cpuidle.text section
MIPS: Fix idle VS timer enqueue
KVM x86 fixes for 6.15-rcN
- Forcibly leave SMM on SHUTDOWN interception on AMD CPUs to avoid causing
problems due to KVM stuffing INIT on SHUTDOWN (KVM needs to sanitize the
VMCB as its state is undefined after SHUTDOWN, emulating INIT is the
least awful choice).
- Track the valid sync/dirty fields in kvm_run as a u64 to ensure KVM
KVM doesn't goof a sanity check in the future.
- Free obsolete roots when (re)loading the MMU to fix a bug where
pre-faulting memory can get stuck due to always encountering a stale
root.
- When dumping GHCB state, use KVM's snapshot instead of the raw GHCB page
to print state, so that KVM doesn't print stale/wrong information.
- When changing memory attributes (e.g. shared <=> private), add potential
hugepage ranges to the mmu_invalidate_range_{start,end} set so that KVM
doesn't create a shared/private hugepage when the the corresponding
attributes will become mixed (the attributes are commited *after* KVM
finishes the invalidation).
- Rework the SRSO mitigation to enable BP_SPEC_REDUCE only when KVM has at
least one active VM. Effectively BP_SPEC_REDUCE when KVM is loaded led
to very measurable performance regressions for non-KVM workloads.
Pull x86 fix from Ingo Molnar:
"Fix a boot regression on very old x86 CPUs without CPUID support"
* tag 'x86-urgent-2025-05-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode: Consolidate the loader enablement checking
Fix MAX_REG_OFFSET to point to the last register in 'pt_regs' and not to
the marker itself, which could allow regs_get_register() to return an
invalid offset.
Fixes: 40e084a506eb ("MIPS: Add uprobes support.")
Suggested-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
KVM/arm64 fixes for 6.15, round #3
- Avoid use of uninitialized memcache pointer in user_mem_abort()
- Always set HCR_EL2.xMO bits when running in VHE, allowing interrupts
to be taken while TGE=0 and fixing an ugly bug on AmpereOne that
occurs when taking an interrupt while clearing the xMO bits
(AC03_CPU_36)
- Prevent VMMs from hiding support for AArch64 at any EL virtualized by
KVM
- Save/restore the host value for HCRX_EL2 instead of restoring an
incorrect fixed value
- Make host_stage2_set_owner_locked() check that the entire requested
range is memory rather than just the first page
Set the magic BP_SPEC_REDUCE bit to mitigate SRSO when running VMs if and
only if KVM has at least one active VM. Leaving the bit set at all times
unfortunately degrades performance by a wee bit more than expected.
Use a dedicated spinlock and counter instead of hooking virtualization
enablement, as changing the behavior of kvm.enable_virt_at_load based on
SRSO_BP_SPEC_REDUCE is painful, and has its own drawbacks, e.g. could
result in performance issues for flows that are sensitive to VM creation
latency.
Defer setting BP_SPEC_REDUCE until VMRUN is imminent to avoid impacting
performance on CPUs that aren't running VMs, e.g. if a setup is using
housekeeping CPUs. Setting BP_SPEC_REDUCE in task context, i.e. without
blasting IPIs to all CPUs, also helps avoid serializing 1<=>N transitions
without incurring a gross amount of complexity (see the Link for details
on how ugly coordinating via IPIs gets).
Link: https://lore.kernel.org/all/aBOnzNCngyS_pQIW@google.com
Fixes: 8442df2b49ed ("x86/bugs: KVM: Add support for SRSO_MSR_FIX")
Reported-by: Michael Larabel <Michael@michaellarabel.com>
Closes: https://www.phoronix.com/review/linux-615-amd-regression
Cc: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250505180300.973137-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Pull misc timers fixes from Ingo Molnar:
- Fix time keeping bugs in CLOCK_MONOTONIC_COARSE clocks
- Work around absolute relocations into vDSO code that GCC erroneously
emits in certain arm64 build environments
- Fix a false positive lockdep warning in the i8253 clocksource driver
* tag 'timers-urgent-2025-05-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/i8253: Use raw_spinlock_irqsave() in clockevent_i8253_disable()
arm64: vdso: Work around invalid absolute relocations from GCC
timekeeping: Prevent coarse clocks going backwards
Consolidate the whole logic which determines whether the microcode loader
should be enabled or not into a single function and call it everywhere.
Well, almost everywhere - not in mk_early_pgtbl_32() because there the kernel
is running without paging enabled and checking dis_ucode_ldr et al would
require physical addresses and uglification of the code.
But since this is 32-bit, the easier thing to do is to simply map the initrd
unconditionally especially since that mapping is getting removed later anyway
by zap_early_initrd_mapping() and avoid the uglification.
In doing so, address the issue of old 486er machines without CPUID
support, not booting current kernels.
[ mingo: Fix no previous prototype for ‘microcode_loader_disabled’ [-Wmissing-prototypes] ]
Fixes: 4c585af7180c1 ("x86/boot/32: Temporarily map initrd for microcode loading")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/CANpbe9Wm3z8fy9HbgS8cuhoj0TREYEEkBipDuhgkWFvqX0UoVQ@mail.gmail.com
Check the return values of kcalloc() and exit early to avoid potential
NULL pointer dereferences.
Compile-tested only.
Cc: stable@vger.kernel.org
Fixes: 75fa6a583882e ("MIPS: CPS: Introduce struct cluster_boot_config")
Fixes: 0856c143e1cd3 ("MIPS: CPS: Boot CPUs in secondary clusters")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
KVM/riscv fixes for 6.15, take #1
- Add missing reset of smstateen CSRs
I found this simple bug while preparing some patches for pKVM.
AFAICT, it should be harmless (besides crashing the kernel if it
was misbehaving)
Fixes: e94a7dea2972 ("KVM: arm64: Move host page ownership tracking to the hyp vmemmap")
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20250501162450.2784043-1-smostafa@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
When changing memory attributes on a subset of a potential hugepage, add
the hugepage to the invalidation range tracking to prevent installing a
hugepage until the attributes are fully updated. Like the actual hugepage
tracking updates in kvm_arch_post_set_memory_attributes(), process only
the head and tail pages, as any potential hugepages that are entirely
covered by the range will already be tracked.
Note, only hugepage chunks whose current attributes are NOT mixed need to
be added to the invalidation set, as mixed attributes already prevent
installing a hugepage, and it's perfectly safe to install a smaller
mapping for a gfn whose attributes aren't changing.
Fixes: 8dd2eee9d526 ("KVM: x86/mmu: Handle page fault for private memory")
Cc: stable@vger.kernel.org
Reported-by: Michael Roth <michael.roth@amd.com>
Tested-by: Michael Roth <michael.roth@amd.com>
Link: https://lore.kernel.org/r/20250430220954.522672-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Pull input fixes from Dmitry Torokhov:
- Synaptics touchpad on multiple laptops (Dynabook Portege X30L-G,
Dynabook Portege X30-D, TUXEDO InfinityBook Pro 14 v5, Dell Precision
M3800, HP Elitebook 850 G1) switched from PS/2 to SMBus mode
- a number of new controllers added to xpad driver: HORI Drum
controller, PowerA Fusion Pro 4, PowerA MOGA XP-Ultra controller,
8BitDo Ultimate 2 Wireless Controller, 8BitDo Ultimate 3-mode
Controller, Hyperkin DuchesS Xbox One controller
- fixes to xpad driver to properly handle Mad Catz JOYTECH NEO SE
Advanced and PDP Mirror's Edge Official controllers
- fixes to xpad driver to properly handle "Share" button on some
controllers
- a fix for device initialization timing and for waking up the
controller in cyttsp5 driver
- a fix for hisi_powerkey driver to properly wake up from s2idle state
- other assorted cleanups and fixes
* tag 'input-for-v6.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: xpad - fix xpad_device sorting
Input: xpad - add support for several more controllers
Input: xpad - fix Share button on Xbox One controllers
Input: xpad - fix two controller table values
Input: hisi_powerkey - enable system-wakeup for s2idle
Input: synaptics - enable InterTouch on Dell Precision M3800
Input: synaptics - enable InterTouch on TUXEDO InfinityBook Pro 14 v5
Input: synaptics - enable InterTouch on Dynabook Portege X30L-G
Input: synaptics - enable InterTouch on Dynabook Portege X30-D
Input: synaptics - enable SMBus for HP Elitebook 850 G1
Input: mtk-pmic-keys - fix possible null pointer dereference
Input: xpad - add support for 8BitDo Ultimate 2 Wireless Controller
Input: cyttsp5 - fix power control issue on wakeup
MAINTAINERS: .mailmap: update Mattijs Korpershoek's email address
dt-bindings: mediatek,mt6779-keypad: Update Mattijs' email address
Input: stmpe-ts - use module alias instead of device table
Input: cyttsp5 - ensure minimum reset pulse width
Input: sparcspkr - avoid unannotated fall-through
input/joystick: magellan: Mark __nonstring look-up table
On x86 during boot, clockevent_i8253_disable() can be invoked via
x86_late_time_init -> hpet_time_init() -> pit_timer_init() which happens
with enabled interrupts.
If some of the old i8253 hardware is actually used then lockdep will notice
that i8253_lock is used in hard interrupt context. This causes lockdep to
complain because it observed the lock being acquired with interrupts
enabled and in hard interrupt context.
Make clockevent_i8253_disable() acquire the lock with
raw_spinlock_irqsave() to cure this.
[ tglx: Massage change log and use guard() ]
Fixes: c8c4076723dac ("x86/timer: Skip PIT initialization on modern chipsets")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250404133116.p-XRWJXf@linutronix.de
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