Pull Hyper-V updates from Wei Liu:

 - Debugfs support for MSHV statistics (Nuno Das Neves)

 - Support for the integrated scheduler (Stanislav Kinsburskii)

 - Various fixes for MSHV memory management and hypervisor status
   handling (Stanislav Kinsburskii)

 - Expose more capabilities and flags for MSHV partition management
   (Anatol Belski, Muminul Islam, Magnus Kulke)

 - Miscellaneous fixes to improve code quality and stability (Carlos
   López, Ethan Nelson-Moore, Li RongQing, Michael Kelley, Mukesh
   Rathor, Purna Pavan Chandra Aekkaladevi, Stanislav Kinsburskii, Uros
   Bizjak)

 - PREEMPT_RT fixes for vmbus interrupts (Jan Kiszka)

* tag 'hyperv-next-signed-20260218' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (34 commits)
  mshv: Handle insufficient root memory hypervisor statuses
  mshv: Handle insufficient contiguous memory hypervisor status
  mshv: Introduce hv_deposit_memory helper functions
  mshv: Introduce hv_result_needs_memory() helper function
  mshv: Add SMT_ENABLED_GUEST partition creation flag
  mshv: Add nested virtualization creation flag
  Drivers: hv: vmbus: Simplify allocation of vmbus_evt
  mshv: expose the scrub partition hypercall
  mshv: Add support for integrated scheduler
  mshv: Use try_cmpxchg() instead of cmpxchg()
  x86/hyperv: Fix error pointer dereference
  x86/hyperv: Reserve 3 interrupt vectors used exclusively by MSHV
  Drivers: hv: vmbus: Use kthread for vmbus interrupts on PREEMPT_RT
  x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn
  x86/hyperv: Use savesegment() instead of inline asm() to save segment registers
  mshv: fix SRCU protection in irqfd resampler ack handler
  mshv: make field names descriptive in a header struct
  x86/hyperv: Update comment in hyperv_cleanup()
  mshv: clear eventfd counter on irqfd shutdown
  x86/hyperv: Use memremap()/memunmap() instead of ioremap_cache()/iounmap()
  ...

When creating guest partition objects, the hypervisor may fail to
allocate root partition pages and return an insufficient memory status.
In this case, deposit memory using the root partition ID instead.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Mukesh R <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

The HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY status indicates that the
hypervisor lacks sufficient contiguous memory for its internal allocations.

When this status is encountered, allocate and deposit
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES contiguous pages to the hypervisor.
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES is defined in the hypervisor headers, a
deposit of this size will always satisfy the hypervisor's requirements.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Mukesh R <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Add support for HV_PARTITION_CREATION_FLAG_SMT_ENABLED_GUEST
to allow userspace VMMs to enable SMT for guest partitions.

Expose this via new MSHV_PT_BIT_SMT_ENABLED_GUEST flag in the UAPI.

Without this flag, the hypervisor schedules guest VPs incorrectly,
causing SMT unusable.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Introduce HV_PARTITION_CREATION_FLAG_NESTED_VIRTUALIZATION_CAPABLE to
indicate support for nested virtualization during partition creation.

This enables clearer configuration and capability checks for nested
virtualization scenarios.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Signed-off-by: Muminul Islam <muislam@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

This hypercall needs to be exposed for VMMs to soft-reboot guests. It
will reset APIC and synthetic interrupt controller state, among others.

Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Query the hypervisor for integrated scheduler support and use it if
configured.

Microsoft Hypervisor originally provided two schedulers: root and core. The
root scheduler allows the root partition to schedule guest vCPUs across
physical cores, supporting both time slicing and CPU affinity (e.g., via
cgroups). In contrast, the core scheduler delegates vCPU-to-physical-core
scheduling entirely to the hypervisor.

Direct virtualization introduces a new privileged guest partition type - L1
Virtual Host (L1VH) — which can create child partitions from its own
resources. These child partitions are effectively siblings, scheduled by
the hypervisor's core scheduler. This prevents the L1VH parent from setting
affinity or time slicing for its own processes or guest VPs. While cgroups,
CFS, and cpuset controllers can still be used, their effectiveness is
unpredictable, as the core scheduler swaps vCPUs according to its own logic
(typically round-robin across all allocated physical CPUs). As a result,
the system may appear to "steal" time from the L1VH and its children.

To address this, Microsoft Hypervisor introduces the integrated scheduler.
This allows an L1VH partition to schedule its own vCPUs and those of its
guests across its "physical" cores, effectively emulating root scheduler
behavior within the L1VH, while retaining core scheduler behavior for the
rest of the system.

The integrated scheduler is controlled by the root partition and gated by
the vmm_enable_integrated_scheduler capability bit. If set, the hypervisor
supports the integrated scheduler. The L1VH partition must then check if it
is enabled by querying the corresponding extended partition property. If
this property is true, the L1VH partition must use the root scheduler
logic; otherwise, it must use the core scheduler. This requirement makes
reading VMM capabilities in L1VH partition a requirement too.

Signed-off-by: Andreea Pintilie <anpintil@microsoft.com>
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

KVM SVM changes for 6.20

 - Drop a user-triggerable WARN on nested_svm_load_cr3() failure.

 - Add support for virtualizing ERAPS.  Note, correct virtualization of ERAPS
   relies on an upcoming, publicly announced change in the APM to reduce the
   set of conditions where hardware (i.e. KVM) *must* flush the RAP.

 - Ignore nSVM intercepts for instructions that are not supported according to
   L1's virtual CPU model.

 - Add support for expedited writes to the fast MMIO bus, a la VMX's fastpath
   for EPT Misconfig.

 - Don't set GIF when clearing EFER.SVME, as GIF exists independently of SVM,
   and allow userspace to restore nested state with GIF=0.

 - Treat exit_code as an unsigned 64-bit value through all of KVM.

 - Add support for fetching SNP certificates from userspace.

 - Fix a bug where KVM would use vmcb02 instead of vmcb01 when emulating VMLOAD
   or VMSAVE on behalf of L2.

 - Misc fixes and cleanups.

hv_stats_page belongs in hvhdk.h, move it there.

It does not require a union to access the data for different counters,
just use a single u64 array for simplicity and to match the Windows
definitions.

While at it, correct the ARM64 value for VpRootDispatchThreadBlocked.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Acked-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Add definitions required for handling GPA intercepts on arm64.

Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>