KVM x86 misc changes for 7.3

 - Fix VPID virtualization bugs where KVM would fail to flush hardware TLBs.

 - Harden the SNP and TDX "populate" ioctls against bad input, and to prepare
   for supporting in-place private<=>shared conversion.

 - Fix a variety of #DB priority bugs.

 - Fix a class of races related to enabling Hyper-V emulation on a vCPU after
   the vCPU is visible to the rest of KVM.

 - Use static calls for nested virtualization ops.

 - Move more KVM-internal code out of x86's kvm_host.h.

 - Enumerate support for a variety of Zhaoxin instructions that don't require
   explicit virtualization.

 - Fix missing EFER validation bugs, including in the KVM_SET_SREGS* path.

 - Harden kvm_vcpu_map() against double-mapping and thus leaking references.

 - Misc fixes and cleanups, e.g. for largely benign syzkaller splats.

KVM selftests changes for 7.3, part 2

 - Fix several issues with seeding KVM's pRNG, and rework the pRNG APIs to that
   the pRNG can be sanely used in host code, not just guest code.

 - Add an IRQ test to validate virtual IRQ deliverty for IRQs wired up via
   KVM_IRQFD + KVM_SET_GSI_ROUTING, with optional support for triggering IRQs
   via writes to an assigned VFIO device.

 - Add syscall wrappers to assert success on a variety of pthreads and CPU
   affinity APIs.

 - Set vCPU pthread affinity as early as possible to reduce contention issues
   that were surfaced by PREEMPT_LAZY, which result in runtimes of over a
   minute on large hosts, versus the expected ~5 seconds.

 - Rework the PMU counters test to run each testcase using a single VM with
   many vCPUs for each sub-testcase, instead of using a unique VM for each
   sub-testcase.  This cuts the runtime by ~20x.

KVM selftests changes for 7.3, part 1

 - Clean up nested SVM's handling of GPRs on L2<=>L1 transitions, reuse the
   functionality for nested VMX, and drop the ucall hack that was fudging
   around the lack of GPR switching on nVMX.

 - Add a stress test to verify KVM doesn't clobber/drop #PF state, e.g. CR2,
   across save/restore, including when L2 is active.

 - Add a test to verify KVM_CREATE_VM accepts exactly what is reported by
   KVM_CAP_VM_TYPES.

 - Misc selftests fixes and cleanups

KVM/riscv changes for 7.3

- Svadu/Zicfiss/Zicfilp FWFT support for Guest
- Use try_cmpxchg for IMSIC MRIF RMW
- More arch-specific tracepoints in KVM RISC-V
- Eager Page Splitting for KVM RISC-V
- Optimize hfence request handling for SMP Guests
- Improve dirty log clearing by skipping zero bits in mask
- Guard HFENCE range loops against overflow
- CPU PM notifiers in KVM RISC-V for non-retentive idle states
- Fix kernel-mode vector context save/restore for Guest

To reduce the runtime of the PMU counters test by an order of magnitude,
create one VM per category of test (arch events, GP PMCs, fixed PMCs),
with N vCPUs per VM, where 'N' is the number of testscases to run per
category.  The vast majority of the test's runtime is spent creating VMs,
because while creating a VM only takes a few milliseconds, the total time
adds up when creating hundreds of VMs.  The only reason the test creates
so many VMs is because KVM disallows changing the virtual PMU model after
a vCPU runs, so rather than create an entirely new VM just to get a "fresh"
vCPUs, simply use a different vCPU.

On an Emerald Rapids host, this reduces the runtime from 75+ seconds to
less than 6 seconds.

Opportunistically fix a typo in the comment about unavailable_masks pointed
out by Like Xu[1].

Link: https://lore.kernel.org/all/20260625090155.6326-1-likexu@tencent.com[1]
Link: https://patch.msgid.link/20260804210046.3413149-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Tidy up the x86 vPMU emulation code and its selftests by fixing comments
that no longer reflect the code along with assorted spelling and grammar
mistakes, and by dropping redundant blank lines reported by checkpatch.

No functional change intended.

Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://patch.msgid.link/20260625090155.6326-1-likexu@tencent.com
[sean: keep quotes around "hit", shove sequences fix into separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

To significantly reduce the PMU counter test's runtime, without sacrificing
test coverage in the aggregate, test a random GP counter in the arch events
testcase instead of testing every possible GP counter.  Testing every PMC
in every run of the test significantly increases the runtime of the test,
without providing an equivalent increase in validation coverage, as the
odds of a KVM having a bug that only affected a subset of counters and only
when testing all other counters are extremely low.

Opportunistically clean up kvm_random_u64_in_range() to eliminate
unnecessary newlines.

Link: https://patch.msgid.link/20260804210046.3413149-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM_CAP_VM_TYPES advertises the bitmap of VM types that KVM_CREATE_VM
accepts, but nothing verified that the ioctl actually enforces it: that
every advertised type can be created and every non-advertised type is
rejected. sev_init2_tests carried a TODO for this ("check that
unsupported types cannot be created. Probably a separate selftest"),
but the check is not specific to SEV or KVM_SEV_INIT2, and not even to
x86.

Add a standalone test that walks the type space and, for each value,
asserts that KVM_CREATE_VM succeeds iff the corresponding bit is set in
KVM_CAP_VM_TYPES, and otherwise fails with -EINVAL. The walk extends
past bit 31 so that out-of-range type values, which can never be
advertised in the u32 bitmap, are also confirmed to be rejected. The
test only depends on KVM_CAP_VM_TYPES, so it lives in the common set and
is skipped on architectures that don't advertise the capability.

Drop the now-addressed TODO from sev_init2_tests.c.

Tested on an AMD SEV-SNP capable host. With KVM_CAP_VM_TYPES=0x15
(DEFAULT/SEV/SNP), only the advertised types are created and everything
else is rejected:

  $ strace -e trace=ioctl ./vm_types_test 2>&1 | grep KVM_CREATE_VM
  ioctl(3, KVM_CREATE_VM, 0)    = 4              # DEFAULT
  ioctl(3, KVM_CREATE_VM, 0x1)  = -1 EINVAL      # SW_PROTECTED
  ioctl(3, KVM_CREATE_VM, 0x2)  = 4              # SEV
  ioctl(3, KVM_CREATE_VM, 0x3)  = -1 EINVAL      # SEV-ES
  ioctl(3, KVM_CREATE_VM, 0x4)  = 4              # SNP
  ioctl(3, KVM_CREATE_VM, 0x5)  = -1 EINVAL      # TDX
  ... 0x6..0x3f all -1 EINVAL ...

Reloading kvm_amd with sev_snp=0 drops the bitmap to 0x5 and only types
0 and 2 are then created, confirming the test tracks the advertised set
rather than hard-coded types.

Signed-off-by: Hemanth Selam <hemanth.selam@gmail.com>
Link: https://patch.msgid.link/20260710050442.826777-1-hemanth.selam@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Extend the invalid nVMX guest state to cover RSM, i.e. to validate that KVM
synthesizes SHUTDOWN for L1 if SMRAM is clobbered with invalid guest state
during an L2 => SMI => RSM => L2 sequence.

Note, unlike the existing testcase, clobbering SMRAM should result in L1,
not L2, getting SHUTDOWN / TRIPLE_FAULT, as RSM is architecturally defined
to trigger shutdown if the CPU detects invalid state.

Signed-off-by: Hao Zhang <hao_zhang_kdev@163.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://patch.msgid.link/20260731173340.2644656-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

In the invalid nVMX guest state test, extract the creation of the VM and
initial running of the vCPU to get to L2 into helpers so that the common
code can be reused to extend the test to also cover RSM.

Eliminate the unnecessary global "vm", and opportunistically free the VM
after the testcase as there's zero reason not to.

Opportunistically assert that L2 is never resumed after the I/O exit to L1,
e.g. to guard against false passes.

Link: https://patch.msgid.link/20260731173340.2644656-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>