# git rev-parse -q --verify 9f16d5e6f220661f73b36a4be1b21575651d8833^{commit}
9f16d5e6f220661f73b36a4be1b21575651d8833
already have revision, skipping fetch
# git checkout -q -f -B kisskb 9f16d5e6f220661f73b36a4be1b21575651d8833
# git clean -qxdf
# < git log -1
# commit 9f16d5e6f220661f73b36a4be1b21575651d8833
# Merge: 42d9e8b7ccdd 9ee62c33c0fe
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Sat Nov 23 16:00:50 2024 -0800
# 
#     Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
#     
#     Pull kvm updates from Paolo Bonzini:
#      "The biggest change here is eliminating the awful idea that KVM had of
#       essentially guessing which pfns are refcounted pages.
#     
#       The reason to do so was that KVM needs to map both non-refcounted
#       pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
#       VMAs that contain refcounted pages.
#     
#       However, the result was security issues in the past, and more recently
#       the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
#       struct page but is not refcounted. In particular this broke virtio-gpu
#       blob resources (which directly map host graphics buffers into the
#       guest as "vram" for the virtio-gpu device) with the amdgpu driver,
#       because amdgpu allocates non-compound higher order pages and the tail
#       pages could not be mapped into KVM.
#     
#       This requires adjusting all uses of struct page in the
#       per-architecture code, to always work on the pfn whenever possible.
#       The large series that did this, from David Stevens and Sean
#       Christopherson, also cleaned up substantially the set of functions
#       that provided arch code with the pfn for a host virtual addresses.
#     
#       The previous maze of twisty little passages, all different, is
#       replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
#       non-__ versions of these two, and kvm_prefetch_pages) saving almost
#       200 lines of code.
#     
#       ARM:
#     
#        - Support for stage-1 permission indirection (FEAT_S1PIE) and
#          permission overlays (FEAT_S1POE), including nested virt + the
#          emulated page table walker
#     
#        - Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
#          call was introduced in PSCIv1.3 as a mechanism to request
#          hibernation, similar to the S4 state in ACPI
#     
#        - Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
#          part of it, introduce trivial initialization of the host's MPAM
#          context so KVM can use the corresponding traps
#     
#        - PMU support under nested virtualization, honoring the guest
#          hypervisor's trap configuration and event filtering when running a
#          nested guest
#     
#        - Fixes to vgic ITS serialization where stale device/interrupt table
#          entries are not zeroed when the mapping is invalidated by the VM
#     
#        - Avoid emulated MMIO completion if userspace has requested
#          synchronous external abort injection
#     
#        - Various fixes and cleanups affecting pKVM, vCPU initialization, and
#          selftests
#     
#       LoongArch:
#     
#        - Add iocsr and mmio bus simulation in kernel.
#     
#        - Add in-kernel interrupt controller emulation.
#     
#        - Add support for virtualization extensions to the eiointc irqchip.
#     
#       PPC:
#     
#        - Drop lingering and utterly obsolete references to PPC970 KVM, which
#          was removed 10 years ago.
#     
#        - Fix incorrect documentation references to non-existing ioctls
#     
#       RISC-V:
#     
#        - Accelerate KVM RISC-V when running as a guest
#     
#        - Perf support to collect KVM guest statistics from host side
#     
#       s390:
#     
#        - New selftests: more ucontrol selftests and CPU model sanity checks
#     
#        - Support for the gen17 CPU model
#     
#        - List registers supported by KVM_GET/SET_ONE_REG in the
#          documentation
#     
#       x86:
#     
#        - Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
#          improve documentation, harden against unexpected changes.
#     
#          Even if the hardware A/D tracking is disabled, it is possible to
#          use the hardware-defined A/D bits to track if a PFN is Accessed
#          and/or Dirty, and that removes a lot of special cases.
#     
#        - Elide TLB flushes when aging secondary PTEs, as has been done in
#          x86's primary MMU for over 10 years.
#     
#        - Recover huge pages in-place in the TDP MMU when dirty page logging
#          is toggled off, instead of zapping them and waiting until the page
#          is re-accessed to create a huge mapping. This reduces vCPU jitter.
#     
#        - Batch TLB flushes when dirty page logging is toggled off. This
#          reduces the time it takes to disable dirty logging by ~3x.
#     
#        - Remove the shrinker that was (poorly) attempting to reclaim shadow
#          page tables in low-memory situations.
#     
#        - Clean up and optimize KVM's handling of writes to
#          MSR_IA32_APICBASE.
#     
#        - Advertise CPUIDs for new instructions in Clearwater Forest
#     
#        - Quirk KVM's misguided behavior of initialized certain feature MSRs
#          to their maximum supported feature set, which can result in KVM
#          creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
#          a non-zero value results in the vCPU having invalid state if
#          userspace hides PDCM from the guest, which in turn can lead to
#          save/restore failures.
#     
#        - Fix KVM's handling of non-canonical checks for vCPUs that support
#          LA57 to better follow the "architecture", in quotes because the
#          actual behavior is poorly documented. E.g. most MSR writes and
#          descriptor table loads ignore CR4.LA57 and operate purely on
#          whether the CPU supports LA57.
#     
#        - Bypass the register cache when querying CPL from kvm_sched_out(),
#          as filling the cache from IRQ context is generally unsafe; harden
#          the cache accessors to try to prevent similar issues from occuring
#          in the future. The issue that triggered this change was already
#          fixed in 6.12, but was still kinda latent.
#     
#        - Advertise AMD_IBPB_RET to userspace, and fix a related bug where
#          KVM over-advertises SPEC_CTRL when trying to support cross-vendor
#          VMs.
#     
#        - Minor cleanups
#     
#        - Switch hugepage recovery thread to use vhost_task.
#     
#          These kthreads can consume significant amounts of CPU time on
#          behalf of a VM or in response to how the VM behaves (for example
#          how it accesses its memory); therefore KVM tried to place the
#          thread in the VM's cgroups and charge the CPU time consumed by that
#          work to the VM's container.
#     
#          However the kthreads did not process SIGSTOP/SIGCONT, and therefore
#          cgroups which had KVM instances inside could not complete freezing.
#     
#          Fix this by replacing the kthread with a PF_USER_WORKER thread, via
#          the vhost_task abstraction. Another 100+ lines removed, with
#          generally better behavior too like having these threads properly
#          parented in the process tree.
#     
#        - Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
#          didn't really work; there was really nothing to work around anyway:
#          the broken patch was meant to fix nested virtualization, but the
#          PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
#          erratum.
#     
#        - Fix 6.12 regression where CONFIG_KVM will be built as a module even
#          if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
#          'y'.
#     
#       x86 selftests:
#     
#        - x86 selftests can now use AVX.
#     
#       Documentation:
#     
#        - Use rST internal links
#     
#        - Reorganize the introduction to the API document
#     
#       Generic:
#     
#        - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
#          instead of RCU, so that running a vCPU on a different task doesn't
#          encounter long due to having to wait for all CPUs become quiescent.
#     
#          In general both reads and writes are rare, but userspace that
#          supports confidential computing is introducing the use of "helper"
#          vCPUs that may jump from one host processor to another. Those will
#          be very happy to trigger a synchronize_rcu(), and the effect on
#          performance is quite the disaster"
#     
#     * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
#       KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
#       KVM: x86: add back X86_LOCAL_APIC dependency
#       Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
#       KVM: x86: switch hugepage recovery thread to vhost_task
#       KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
#       x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
#       Documentation: KVM: fix malformed table
#       irqchip/loongson-eiointc: Add virt extension support
#       LoongArch: KVM: Add irqfd support
#       LoongArch: KVM: Add PCHPIC user mode read and write functions
#       LoongArch: KVM: Add PCHPIC read and write functions
#       LoongArch: KVM: Add PCHPIC device support
#       LoongArch: KVM: Add EIOINTC user mode read and write functions
#       LoongArch: KVM: Add EIOINTC read and write functions
#       LoongArch: KVM: Add EIOINTC device support
#       LoongArch: KVM: Add IPI user mode read and write function
#       LoongArch: KVM: Add IPI read and write function
#       LoongArch: KVM: Add IPI device support
#       LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
#       KVM: arm64: Pass on SVE mapping failures
#       ...
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-ld --version
# < git log --format=%s --max-count=1 9f16d5e6f220661f73b36a4be1b21575651d8833
# make -s -j 160 ARCH=mips O=/kisskb/build/linus_32r6_defconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-  32r6_defconfig
Using /kisskb/src/arch/mips/configs/generic_defconfig as base
Merging /kisskb/src/arch/mips/configs/generic/32r6.config
Merging /kisskb/src/arch/mips/configs/generic/eb.config
Merging /kisskb/src/arch/mips/configs/generic/board-boston.config
Merging /kisskb/src/arch/mips/configs/generic/board-litex.config
Merging /kisskb/src/arch/mips/configs/generic/board-marduk.config
Merging /kisskb/src/arch/mips/configs/generic/board-ranchu.config
Merging /kisskb/src/arch/mips/configs/generic/board-sead-3.config
Merging /kisskb/src/arch/mips/configs/generic/board-virt.config
# < make -s -j 160 ARCH=mips O=/kisskb/build/linus_32r6_defconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-  help
# make -s -j 160 ARCH=mips O=/kisskb/build/linus_32r6_defconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-  olddefconfig
# make -s -j 160 ARCH=mips O=/kisskb/build/linus_32r6_defconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-  
/kisskb/src/arch/mips/boot/dts/img/boston.dts:128.17-178.5: Warning (interrupt_provider): /pci@14000000/pci2_root@0,0: '#interrupt-cells' found, but node is not an interrupt provider
/kisskb/src/arch/mips/boot/dts/img/boston.dts:136.23-177.6: Warning (interrupt_provider): /pci@14000000/pci2_root@0,0/eg20t_bridge@1,0,0: '#interrupt-cells' found, but node is not an interrupt provider
arch/mips/boot/dts/img/boston.dtb: Warning (interrupt_map): Failed prerequisite 'interrupt_provider'
Completed OK
# rm -rf /kisskb/build/linus_32r6_defconfig_mips-gcc13
# Build took: 0:01:02.784801