<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/include/uapi, branch v6.17</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2025-07-10T16:06:53+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-07-10T16:06:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=73d7cf07109e79b093d1a1fb57a88d4048cd9b4b'/>
<id>73d7cf07109e79b093d1a1fb57a88d4048cd9b4b</id>
<content type='text'>
Pull KVM fixes from Paolo Bonzini:
 "Many patches, pretty much all of them small, that accumulated while I
  was on vacation.

  ARM:

   - Remove the last leftovers of the ill-fated FPSIMD host state
     mapping at EL2 stage-1

   - Fix unexpected advertisement to the guest of unimplemented S2 base
     granule sizes

   - Gracefully fail initialising pKVM if the interrupt controller isn't
     GICv3

   - Also gracefully fail initialising pKVM if the carveout allocation
     fails

   - Fix the computing of the minimum MMIO range required for the host
     on stage-2 fault

   - Fix the generation of the GICv3 Maintenance Interrupt in nested
     mode

  x86:

   - Reject SEV{-ES} intra-host migration if one or more vCPUs are
     actively being created, so as not to create a non-SEV{-ES} vCPU in
     an SEV{-ES} VM

   - Use a pre-allocated, per-vCPU buffer for handling de-sparsification
     of vCPU masks in Hyper-V hypercalls; fixes a "stack frame too
     large" issue

   - Allow out-of-range/invalid Xen event channel ports when configuring
     IRQ routing, to avoid dictating a specific ioctl() ordering to
     userspace

   - Conditionally reschedule when setting memory attributes to avoid
     soft lockups when userspace converts huge swaths of memory to/from
     private

   - Add back MWAIT as a required feature for the MONITOR/MWAIT selftest

   - Add a missing field in struct sev_data_snp_launch_start that
     resulted in the guest-visible workarounds field being filled at the
     wrong offset

   - Skip non-canonical address when processing Hyper-V PV TLB flushes
     to avoid VM-Fail on INVVPID

   - Advertise supported TDX TDVMCALLs to userspace

   - Pass SetupEventNotifyInterrupt arguments to userspace

   - Fix TSC frequency underflow"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: avoid underflow when scaling TSC frequency
  KVM: arm64: Remove kvm_arch_vcpu_run_map_fp()
  KVM: arm64: Fix handling of FEAT_GTG for unimplemented granule sizes
  KVM: arm64: Don't free hyp pages with pKVM on GICv2
  KVM: arm64: Fix error path in init_hyp_mode()
  KVM: arm64: Adjust range correctly during host stage-2 faults
  KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()
  KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
  KVM: SVM: Add missing member in SNP_LAUNCH_START command structure
  Documentation: KVM: Fix unexpected unindent warnings
  KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
  KVM: Allow CPU to reschedule while setting per-page memory attributes
  KVM: x86/xen: Allow 'out of range' event channel ports in IRQ routing table.
  KVM: x86/hyper-v: Use preallocated per-vCPU buffer for de-sparsified vCPU masks
  KVM: SVM: Initialize vmsa_pa in VMCB to INVALID_PAGE if VMSA page is NULL
  KVM: SVM: Reject SEV{-ES} intra host migration if vCPU creation is in-flight
  KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
  KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull KVM fixes from Paolo Bonzini:
 "Many patches, pretty much all of them small, that accumulated while I
  was on vacation.

  ARM:

   - Remove the last leftovers of the ill-fated FPSIMD host state
     mapping at EL2 stage-1

   - Fix unexpected advertisement to the guest of unimplemented S2 base
     granule sizes

   - Gracefully fail initialising pKVM if the interrupt controller isn't
     GICv3

   - Also gracefully fail initialising pKVM if the carveout allocation
     fails

   - Fix the computing of the minimum MMIO range required for the host
     on stage-2 fault

   - Fix the generation of the GICv3 Maintenance Interrupt in nested
     mode

  x86:

   - Reject SEV{-ES} intra-host migration if one or more vCPUs are
     actively being created, so as not to create a non-SEV{-ES} vCPU in
     an SEV{-ES} VM

   - Use a pre-allocated, per-vCPU buffer for handling de-sparsification
     of vCPU masks in Hyper-V hypercalls; fixes a "stack frame too
     large" issue

   - Allow out-of-range/invalid Xen event channel ports when configuring
     IRQ routing, to avoid dictating a specific ioctl() ordering to
     userspace

   - Conditionally reschedule when setting memory attributes to avoid
     soft lockups when userspace converts huge swaths of memory to/from
     private

   - Add back MWAIT as a required feature for the MONITOR/MWAIT selftest

   - Add a missing field in struct sev_data_snp_launch_start that
     resulted in the guest-visible workarounds field being filled at the
     wrong offset

   - Skip non-canonical address when processing Hyper-V PV TLB flushes
     to avoid VM-Fail on INVVPID

   - Advertise supported TDX TDVMCALLs to userspace

   - Pass SetupEventNotifyInterrupt arguments to userspace

   - Fix TSC frequency underflow"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: avoid underflow when scaling TSC frequency
  KVM: arm64: Remove kvm_arch_vcpu_run_map_fp()
  KVM: arm64: Fix handling of FEAT_GTG for unimplemented granule sizes
  KVM: arm64: Don't free hyp pages with pKVM on GICv2
  KVM: arm64: Fix error path in init_hyp_mode()
  KVM: arm64: Adjust range correctly during host stage-2 faults
  KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()
  KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
  KVM: SVM: Add missing member in SNP_LAUNCH_START command structure
  Documentation: KVM: Fix unexpected unindent warnings
  KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
  KVM: Allow CPU to reschedule while setting per-page memory attributes
  KVM: x86/xen: Allow 'out of range' event channel ports in IRQ routing table.
  KVM: x86/hyper-v: Use preallocated per-vCPU buffer for de-sparsified vCPU masks
  KVM: SVM: Initialize vmsa_pa in VMCB to INVALID_PAGE if VMSA page is NULL
  KVM: SVM: Reject SEV{-ES} intra host migration if vCPU creation is in-flight
  KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
  KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/traps: Initialize DR6 by writing its architectural reset value</title>
<updated>2025-06-24T20:15:51+00:00</updated>
<author>
<name>Xin Li (Intel)</name>
<email>xin@zytor.com</email>
</author>
<published>2025-06-20T23:15:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5f465c148c61e876b6d6eacd8e8e365f2d47758f'/>
<id>5f465c148c61e876b6d6eacd8e8e365f2d47758f</id>
<content type='text'>
Initialize DR6 by writing its architectural reset value to avoid
incorrectly zeroing DR6 to clear DR6.BLD at boot time, which leads
to a false bus lock detected warning.

The Intel SDM says:

  1) Certain debug exceptions may clear bits 0-3 of DR6.

  2) BLD induced #DB clears DR6.BLD and any other debug exception
     doesn't modify DR6.BLD.

  3) RTM induced #DB clears DR6.RTM and any other debug exception
     sets DR6.RTM.

  To avoid confusion in identifying debug exceptions, debug handlers
  should set DR6.BLD and DR6.RTM, and clear other DR6 bits before
  returning.

The DR6 architectural reset value 0xFFFF0FF0, already defined as
macro DR6_RESERVED, satisfies these requirements, so just use it to
reinitialize DR6 whenever needed.

Since clear_all_debug_regs() no longer zeros all debug registers,
rename it to initialize_debug_regs() to better reflect its current
behavior.

Since debug_read_clear_dr6() no longer clears DR6, rename it to
debug_read_reset_dr6() to better reflect its current behavior.

Fixes: ebb1064e7c2e9 ("x86/traps: Handle #DB for bus lock")
Reported-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Suggested-by: H. Peter Anvin (Intel) &lt;hpa@zytor.com&gt;
Signed-off-by: Xin Li (Intel) &lt;xin@zytor.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: H. Peter Anvin (Intel) &lt;hpa@zytor.com&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Link: https://lore.kernel.org/lkml/06e68373-a92b-472e-8fd9-ba548119770c@intel.com/
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250620231504.2676902-2-xin%40zytor.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Initialize DR6 by writing its architectural reset value to avoid
incorrectly zeroing DR6 to clear DR6.BLD at boot time, which leads
to a false bus lock detected warning.

The Intel SDM says:

  1) Certain debug exceptions may clear bits 0-3 of DR6.

  2) BLD induced #DB clears DR6.BLD and any other debug exception
     doesn't modify DR6.BLD.

  3) RTM induced #DB clears DR6.RTM and any other debug exception
     sets DR6.RTM.

  To avoid confusion in identifying debug exceptions, debug handlers
  should set DR6.BLD and DR6.RTM, and clear other DR6 bits before
  returning.

The DR6 architectural reset value 0xFFFF0FF0, already defined as
macro DR6_RESERVED, satisfies these requirements, so just use it to
reinitialize DR6 whenever needed.

Since clear_all_debug_regs() no longer zeros all debug registers,
rename it to initialize_debug_regs() to better reflect its current
behavior.

Since debug_read_clear_dr6() no longer clears DR6, rename it to
debug_read_reset_dr6() to better reflect its current behavior.

Fixes: ebb1064e7c2e9 ("x86/traps: Handle #DB for bus lock")
Reported-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Suggested-by: H. Peter Anvin (Intel) &lt;hpa@zytor.com&gt;
Signed-off-by: Xin Li (Intel) &lt;xin@zytor.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Reviewed-by: H. Peter Anvin (Intel) &lt;hpa@zytor.com&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Link: https://lore.kernel.org/lkml/06e68373-a92b-472e-8fd9-ba548119770c@intel.com/
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250620231504.2676902-2-xin%40zytor.com
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities</title>
<updated>2025-06-20T18:20:20+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-06-20T18:20:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=28224ef02b56fceee2c161fe2a49a0bb197e44f5'/>
<id>28224ef02b56fceee2c161fe2a49a0bb197e44f5</id>
<content type='text'>
Allow userspace to advertise TDG.VP.VMCALL subfunctions that the
kernel also supports.  For each output register of GetTdVmCallInfo's
leaf 1, add two fields to KVM_TDX_CAPABILITIES: one for kernel-supported
TDVMCALLs (userspace can set those blindly) and one for user-supported
TDVMCALLs (userspace can set those if it knows how to handle them).

Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Allow userspace to advertise TDG.VP.VMCALL subfunctions that the
kernel also supports.  For each output register of GetTdVmCallInfo's
leaf 1, add two fields to KVM_TDX_CAPABILITIES: one for kernel-supported
TDVMCALLs (userspace can set those blindly) and one for user-supported
TDVMCALLs (userspace can set those if it knows how to handle them).

Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2025-06-02T19:24:58+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-06-02T19:24:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7f9039c524a351c684149ecf1b3c5145a0dff2fe'/>
<id>7f9039c524a351c684149ecf1b3c5145a0dff2fe</id>
<content type='text'>
Pull more kvm updates from Paolo Bonzini:
  Generic:

   - Clean up locking of all vCPUs for a VM by using the *_nest_lock()
     family of functions, and move duplicated code to virt/kvm/. kernel/
     patches acked by Peter Zijlstra

   - Add MGLRU support to the access tracking perf test

  ARM fixes:

   - Make the irqbypass hooks resilient to changes in the GSI&lt;-&gt;MSI
     routing, avoiding behind stale vLPI mappings being left behind. The
     fix is to resolve the VGIC IRQ using the host IRQ (which is stable)
     and nuking the vLPI mapping upon a routing change

   - Close another VGIC race where vCPU creation races with VGIC
     creation, leading to in-flight vCPUs entering the kernel w/o
     private IRQs allocated

   - Fix a build issue triggered by the recently added workaround for
     Ampere's AC04_CPU_23 erratum

   - Correctly sign-extend the VA when emulating a TLBI instruction
     potentially targeting a VNCR mapping

   - Avoid dereferencing a NULL pointer in the VGIC debug code, which
     can happen if the device doesn't have any mapping yet

  s390:

   - Fix interaction between some filesystems and Secure Execution

   - Some cleanups and refactorings, preparing for an upcoming big
     series

  x86:

   - Wait for target vCPU to ack KVM_REQ_UPDATE_PROTECTED_GUEST_STATE
     to fix a race between AP destroy and VMRUN

   - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for
     the VM

   - Refine and harden handling of spurious faults

   - Add support for ALLOWED_SEV_FEATURES

   - Add #VMGEXIT to the set of handlers special cased for
     CONFIG_RETPOLINE=y

   - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing
     features that utilize those bits

   - Don't account temporary allocations in sev_send_update_data()

   - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock
     Threshold

   - Unify virtualization of IBRS on nested VM-Exit, and cross-vCPU
     IBPB, between SVM and VMX

   - Advertise support to userspace for WRMSRNS and PREFETCHI

   - Rescan I/O APIC routes after handling EOI that needed to be
     intercepted due to the old/previous routing, but not the
     new/current routing

   - Add a module param to control and enumerate support for device
     posted interrupts

   - Fix a potential overflow with nested virt on Intel systems running
     32-bit kernels

   - Flush shadow VMCSes on emergency reboot

   - Add support for SNP to the various SEV selftests

   - Add a selftest to verify fastops instructions via forced emulation

   - Refine and optimize KVM's software processing of the posted
     interrupt bitmap, and share the harvesting code between KVM and the
     kernel's Posted MSI handler"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (93 commits)
  rtmutex_api: provide correct extern functions
  KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointer
  KVM: arm64: vgic-init: Plug vCPU vs. VGIC creation race
  KVM: arm64: Unmap vLPIs affected by changes to GSI routing information
  KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding()
  KVM: arm64: Protect vLPI translation with vgic_irq::irq_lock
  KVM: arm64: Use lock guard in vgic_v4_set_forwarding()
  KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation
  arm64: sysreg: Drag linux/kconfig.h to work around vdso build issue
  KVM: s390: Simplify and move pv code
  KVM: s390: Refactor and split some gmap helpers
  KVM: s390: Remove unneeded srcu lock
  s390: Remove unneeded includes
  s390/uv: Improve splitting of large folios that cannot be split while dirty
  s390/uv: Always return 0 from s390_wiggle_split_folio() if successful
  s390/uv: Don't return 0 from make_hva_secure() if the operation was not successful
  rust: add helper for mutex_trylock
  RISC-V: KVM: use kvm_trylock_all_vcpus when locking all vCPUs
  KVM: arm64: use kvm_trylock_all_vcpus when locking all vCPUs
  x86: KVM: SVM: use kvm_lock_all_vcpus instead of a custom implementation
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more kvm updates from Paolo Bonzini:
  Generic:

   - Clean up locking of all vCPUs for a VM by using the *_nest_lock()
     family of functions, and move duplicated code to virt/kvm/. kernel/
     patches acked by Peter Zijlstra

   - Add MGLRU support to the access tracking perf test

  ARM fixes:

   - Make the irqbypass hooks resilient to changes in the GSI&lt;-&gt;MSI
     routing, avoiding behind stale vLPI mappings being left behind. The
     fix is to resolve the VGIC IRQ using the host IRQ (which is stable)
     and nuking the vLPI mapping upon a routing change

   - Close another VGIC race where vCPU creation races with VGIC
     creation, leading to in-flight vCPUs entering the kernel w/o
     private IRQs allocated

   - Fix a build issue triggered by the recently added workaround for
     Ampere's AC04_CPU_23 erratum

   - Correctly sign-extend the VA when emulating a TLBI instruction
     potentially targeting a VNCR mapping

   - Avoid dereferencing a NULL pointer in the VGIC debug code, which
     can happen if the device doesn't have any mapping yet

  s390:

   - Fix interaction between some filesystems and Secure Execution

   - Some cleanups and refactorings, preparing for an upcoming big
     series

  x86:

   - Wait for target vCPU to ack KVM_REQ_UPDATE_PROTECTED_GUEST_STATE
     to fix a race between AP destroy and VMRUN

   - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for
     the VM

   - Refine and harden handling of spurious faults

   - Add support for ALLOWED_SEV_FEATURES

   - Add #VMGEXIT to the set of handlers special cased for
     CONFIG_RETPOLINE=y

   - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing
     features that utilize those bits

   - Don't account temporary allocations in sev_send_update_data()

   - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock
     Threshold

   - Unify virtualization of IBRS on nested VM-Exit, and cross-vCPU
     IBPB, between SVM and VMX

   - Advertise support to userspace for WRMSRNS and PREFETCHI

   - Rescan I/O APIC routes after handling EOI that needed to be
     intercepted due to the old/previous routing, but not the
     new/current routing

   - Add a module param to control and enumerate support for device
     posted interrupts

   - Fix a potential overflow with nested virt on Intel systems running
     32-bit kernels

   - Flush shadow VMCSes on emergency reboot

   - Add support for SNP to the various SEV selftests

   - Add a selftest to verify fastops instructions via forced emulation

   - Refine and optimize KVM's software processing of the posted
     interrupt bitmap, and share the harvesting code between KVM and the
     kernel's Posted MSI handler"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (93 commits)
  rtmutex_api: provide correct extern functions
  KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointer
  KVM: arm64: vgic-init: Plug vCPU vs. VGIC creation race
  KVM: arm64: Unmap vLPIs affected by changes to GSI routing information
  KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding()
  KVM: arm64: Protect vLPI translation with vgic_irq::irq_lock
  KVM: arm64: Use lock guard in vgic_v4_set_forwarding()
  KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation
  arm64: sysreg: Drag linux/kconfig.h to work around vdso build issue
  KVM: s390: Simplify and move pv code
  KVM: s390: Refactor and split some gmap helpers
  KVM: s390: Remove unneeded srcu lock
  s390: Remove unneeded includes
  s390/uv: Improve splitting of large folios that cannot be split while dirty
  s390/uv: Always return 0 from s390_wiggle_split_folio() if successful
  s390/uv: Don't return 0 from make_hva_secure() if the operation was not successful
  rust: add helper for mutex_trylock
  RISC-V: KVM: use kvm_trylock_all_vcpus when locking all vCPUs
  KVM: arm64: use kvm_trylock_all_vcpus when locking all vCPUs
  x86: KVM: SVM: use kvm_lock_all_vcpus instead of a custom implementation
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2025-05-31T22:44:16+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-05-31T22:44:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=00c010e130e58301db2ea0cec1eadc931e1cb8cf'/>
<id>00c010e130e58301db2ea0cec1eadc931e1cb8cf</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp-&gt;free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp-&gt;free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'kvm-x86-svm-6.16' of https://github.com/kvm-x86/linux into HEAD</title>
<updated>2025-05-27T16:15:49+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-05-27T16:15:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4e02d4f9734fa55e3eb18be9b759cd42d93497ec'/>
<id>4e02d4f9734fa55e3eb18be9b759cd42d93497ec</id>
<content type='text'>
KVM SVM changes for 6.16:

 - Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
   fix a race between AP destroy and VMRUN.

 - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.

 - Add support for ALLOWED_SEV_FEATURES.

 - Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.

 - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
   that utilize those bits.

 - Don't account temporary allocations in sev_send_update_data().

 - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
KVM SVM changes for 6.16:

 - Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
   fix a race between AP destroy and VMRUN.

 - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.

 - Add support for ALLOWED_SEV_FEATURES.

 - Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.

 - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
   that utilize those bits.

 - Don't account temporary allocations in sev_send_update_data().

 - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: SVM: Add architectural definitions/assets for Bus Lock Threshold</title>
<updated>2025-05-16T16:42:08+00:00</updated>
<author>
<name>Nikunj A Dadhania</name>
<email>nikunj@amd.com</email>
</author>
<published>2025-05-02T05:03:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=827547bc3a2a2af6391260de8874008c5a52f238'/>
<id>827547bc3a2a2af6391260de8874008c5a52f238</id>
<content type='text'>
Virtual machines can exploit bus locks to degrade the performance of
the system. Bus locks can be caused by Non-WB(Write back) and
misaligned locked RMW (Read-modify-Write) instructions and require
systemwide synchronization among all processors which can result into
significant performance penalties.

To address this issue, the Bus Lock Threshold feature is introduced to
provide ability to hypervisor to restrict guests' capability of
initiating mulitple buslocks, thereby preventing system slowdowns.

Support for the buslock threshold is indicated via CPUID function
0x8000000A_EDX[29].

On the processors that support the Bus Lock Threshold feature, the
VMCB provides a Bus Lock Threshold enable bit and an unsigned 16-bit
Bus Lock threshold count.

VMCB intercept bit
VMCB Offset     Bits    Function
14h             5       Intercept bus lock operations

Bus lock threshold count
VMCB Offset     Bits    Function
120h            15:0    Bus lock counter

When a VMRUN instruction is executed, the bus lock threshold count is
loaded into an internal count register. Before the processor executes
a bus lock in the guest, it checks the value of this register:

 - If the value is greater than '0', the processor successfully
   executes the bus lock and decrements the count.

 - If the value is '0', the bus lock is not executed, and a #VMEXIT to
   the VMM is taken.

The bus lock threshold #VMEXIT is reported to the VMM with the VMEXIT
code A5h, SVM_EXIT_BUS_LOCK.

Signed-off-by: Nikunj A Dadhania &lt;nikunj@amd.com&gt;
Co-developed-by: Manali Shukla &lt;manali.shukla@amd.com&gt;
Signed-off-by: Manali Shukla &lt;manali.shukla@amd.com&gt;
Link: https://lore.kernel.org/r/20250502050346.14274-4-manali.shukla@amd.com
[sean: rewrite shortlog]
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Virtual machines can exploit bus locks to degrade the performance of
the system. Bus locks can be caused by Non-WB(Write back) and
misaligned locked RMW (Read-modify-Write) instructions and require
systemwide synchronization among all processors which can result into
significant performance penalties.

To address this issue, the Bus Lock Threshold feature is introduced to
provide ability to hypervisor to restrict guests' capability of
initiating mulitple buslocks, thereby preventing system slowdowns.

Support for the buslock threshold is indicated via CPUID function
0x8000000A_EDX[29].

On the processors that support the Bus Lock Threshold feature, the
VMCB provides a Bus Lock Threshold enable bit and an unsigned 16-bit
Bus Lock threshold count.

VMCB intercept bit
VMCB Offset     Bits    Function
14h             5       Intercept bus lock operations

Bus lock threshold count
VMCB Offset     Bits    Function
120h            15:0    Bus lock counter

When a VMRUN instruction is executed, the bus lock threshold count is
loaded into an internal count register. Before the processor executes
a bus lock in the guest, it checks the value of this register:

 - If the value is greater than '0', the processor successfully
   executes the bus lock and decrements the count.

 - If the value is '0', the bus lock is not executed, and a #VMEXIT to
   the VMM is taken.

The bus lock threshold #VMEXIT is reported to the VMM with the VMEXIT
code A5h, SVM_EXIT_BUS_LOCK.

Signed-off-by: Nikunj A Dadhania &lt;nikunj@amd.com&gt;
Co-developed-by: Manali Shukla &lt;manali.shukla@amd.com&gt;
Signed-off-by: Manali Shukla &lt;manali.shukla@amd.com&gt;
Link: https://lore.kernel.org/r/20250502050346.14274-4-manali.shukla@amd.com
[sean: rewrite shortlog]
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/kexec: add support for passing kexec handover (KHO) data</title>
<updated>2025-05-13T06:50:41+00:00</updated>
<author>
<name>Alexander Graf</name>
<email>graf@amazon.com</email>
</author>
<published>2025-05-09T07:46:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=65a5d7278545b5cac3ca0a5b6a1e9a4ea1554181'/>
<id>65a5d7278545b5cac3ca0a5b6a1e9a4ea1554181</id>
<content type='text'>
kexec handover (KHO) creates a metadata that the kernels pass between each
other during kexec.  This metadata is stored in memory and kexec image
contains a (physical) pointer to that memory.

In addition, KHO keeps "scratch regions" available for kexec: physically
contiguous memory regions that are guaranteed to not have any memory that
KHO would preserve.  The new kernel bootstraps itself using the scratch
regions and sets all handed over memory as in use.  When subsystems that
support KHO initialize, they introspect the KHO metadata, restore
preserved memory regions, and retrieve their state stored in the preserved
memory.

Enlighten x86 kexec-file and boot path about the KHO metadata and make
sure it gets passed along to the next kernel.

Link: https://lkml.kernel.org/r/20250509074635.3187114-12-changyuanl@google.com
Signed-off-by: Alexander Graf &lt;graf@amazon.com&gt;
Co-developed-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Signed-off-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Co-developed-by: Changyuan Lyu &lt;changyuanl@google.com&gt;
Signed-off-by: Changyuan Lyu &lt;changyuanl@google.com&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Cc: Ben Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Betkov &lt;bp@alien8.de&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: David Woodhouse &lt;dwmw2@infradead.org&gt;
Cc: Eric Biederman &lt;ebiederm@xmission.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Gowans &lt;jgowans@amazon.com&gt;
Cc: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Krzysztof Kozlowski &lt;krzk@kernel.org&gt;
Cc: Marc Rutland &lt;mark.rutland@arm.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Pasha Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Pratyush Yadav &lt;ptyadav@amazon.de&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Saravana Kannan &lt;saravanak@google.com&gt;
Cc: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleinxer &lt;tglx@linutronix.de&gt;
Cc: Thomas Lendacky &lt;thomas.lendacky@amd.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
kexec handover (KHO) creates a metadata that the kernels pass between each
other during kexec.  This metadata is stored in memory and kexec image
contains a (physical) pointer to that memory.

In addition, KHO keeps "scratch regions" available for kexec: physically
contiguous memory regions that are guaranteed to not have any memory that
KHO would preserve.  The new kernel bootstraps itself using the scratch
regions and sets all handed over memory as in use.  When subsystems that
support KHO initialize, they introspect the KHO metadata, restore
preserved memory regions, and retrieve their state stored in the preserved
memory.

Enlighten x86 kexec-file and boot path about the KHO metadata and make
sure it gets passed along to the next kernel.

Link: https://lkml.kernel.org/r/20250509074635.3187114-12-changyuanl@google.com
Signed-off-by: Alexander Graf &lt;graf@amazon.com&gt;
Co-developed-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Signed-off-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Co-developed-by: Changyuan Lyu &lt;changyuanl@google.com&gt;
Signed-off-by: Changyuan Lyu &lt;changyuanl@google.com&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Cc: Ben Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Betkov &lt;bp@alien8.de&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: David Woodhouse &lt;dwmw2@infradead.org&gt;
Cc: Eric Biederman &lt;ebiederm@xmission.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Gowans &lt;jgowans@amazon.com&gt;
Cc: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Krzysztof Kozlowski &lt;krzk@kernel.org&gt;
Cc: Marc Rutland &lt;mark.rutland@arm.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Pasha Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Pratyush Yadav &lt;ptyadav@amazon.de&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Saravana Kannan &lt;saravanak@google.com&gt;
Cc: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleinxer &lt;tglx@linutronix.de&gt;
Cc: Thomas Lendacky &lt;thomas.lendacky@amd.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: selftests: Add library support for interacting with SNP</title>
<updated>2025-05-02T19:32:33+00:00</updated>
<author>
<name>Pratik R. Sampat</name>
<email>prsampat@amd.com</email>
</author>
<published>2025-03-05T22:59:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3bf3e0a521237681d5353cca741474aa8c4e16de'/>
<id>3bf3e0a521237681d5353cca741474aa8c4e16de</id>
<content type='text'>
Extend the SEV library to include support for SNP ioctl() wrappers,
which aid in launching and interacting with a SEV-SNP guest.

Signed-off-by: Pratik R. Sampat &lt;prsampat@amd.com&gt;
Link: https://lore.kernel.org/r/20250305230000.231025-8-prsampat@amd.com
[sean: use BIT()]
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Extend the SEV library to include support for SNP ioctl() wrappers,
which aid in launching and interacting with a SEV-SNP guest.

Signed-off-by: Pratik R. Sampat &lt;prsampat@amd.com&gt;
Link: https://lore.kernel.org/r/20250305230000.231025-8-prsampat@amd.com
[sean: use BIT()]
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'kvm-tdx-initial' into HEAD</title>
<updated>2025-04-07T11:36:33+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-03-19T13:46:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fd02aa45bda6d2f2fedcab70e828867332ef7e1c'/>
<id>fd02aa45bda6d2f2fedcab70e828867332ef7e1c</id>
<content type='text'>
This large commit contains the initial support for TDX in KVM.  All x86
parts enable the host-side hypercalls that KVM uses to talk to the TDX
module, a software component that runs in a special CPU mode called SEAM
(Secure Arbitration Mode).

The series is in turn split into multiple sub-series, each with a separate
merge commit:

- Initialization: basic setup for using the TDX module from KVM, plus
  ioctls to create TDX VMs and vCPUs.

- MMU: in TDX, private and shared halves of the address space are mapped by
  different EPT roots, and the private half is managed by the TDX module.
  Using the support that was added to the generic MMU code in 6.14,
  add support for TDX's secure page tables to the Intel side of KVM.
  Generic KVM code takes care of maintaining a mirror of the secure page
  tables so that they can be queried efficiently, and ensuring that changes
  are applied to both the mirror and the secure EPT.

- vCPU enter/exit: implement the callbacks that handle the entry of a TDX
  vCPU (via the SEAMCALL TDH.VP.ENTER) and the corresponding save/restore
  of host state.

- Userspace exits: introduce support for guest TDVMCALLs that KVM forwards to
  userspace.  These correspond to the usual KVM_EXIT_* "heavyweight vmexits"
  but are triggered through a different mechanism, similar to VMGEXIT for
  SEV-ES and SEV-SNP.

- Interrupt handling: support for virtual interrupt injection as well as
  handling VM-Exits that are caused by vectored events.  Exclusive to
  TDX are machine-check SMIs, which the kernel already knows how to
  handle through the kernel machine check handler (commit 7911f145de5f,
  "x86/mce: Implement recovery for errors in TDX/SEAM non-root mode")

- Loose ends: handling of the remaining exits from the TDX module, including
  EPT violation/misconfig and several TDVMCALL leaves that are handled in
  the kernel (CPUID, HLT, RDMSR/WRMSR, GetTdVmCallInfo); plus returning
  an error or ignoring operations that are not supported by TDX guests

Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This large commit contains the initial support for TDX in KVM.  All x86
parts enable the host-side hypercalls that KVM uses to talk to the TDX
module, a software component that runs in a special CPU mode called SEAM
(Secure Arbitration Mode).

The series is in turn split into multiple sub-series, each with a separate
merge commit:

- Initialization: basic setup for using the TDX module from KVM, plus
  ioctls to create TDX VMs and vCPUs.

- MMU: in TDX, private and shared halves of the address space are mapped by
  different EPT roots, and the private half is managed by the TDX module.
  Using the support that was added to the generic MMU code in 6.14,
  add support for TDX's secure page tables to the Intel side of KVM.
  Generic KVM code takes care of maintaining a mirror of the secure page
  tables so that they can be queried efficiently, and ensuring that changes
  are applied to both the mirror and the secure EPT.

- vCPU enter/exit: implement the callbacks that handle the entry of a TDX
  vCPU (via the SEAMCALL TDH.VP.ENTER) and the corresponding save/restore
  of host state.

- Userspace exits: introduce support for guest TDVMCALLs that KVM forwards to
  userspace.  These correspond to the usual KVM_EXIT_* "heavyweight vmexits"
  but are triggered through a different mechanism, similar to VMGEXIT for
  SEV-ES and SEV-SNP.

- Interrupt handling: support for virtual interrupt injection as well as
  handling VM-Exits that are caused by vectored events.  Exclusive to
  TDX are machine-check SMIs, which the kernel already knows how to
  handle through the kernel machine check handler (commit 7911f145de5f,
  "x86/mce: Implement recovery for errors in TDX/SEAM non-root mode")

- Loose ends: handling of the remaining exits from the TDX module, including
  EPT violation/misconfig and several TDVMCALL leaves that are handled in
  the kernel (CPUID, HLT, RDMSR/WRMSR, GetTdVmCallInfo); plus returning
  an error or ignoring operations that are not supported by TDX guests

Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
