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

LoongArch KVM changes for v7.3

1. Advertise already-supported capabilities.
2. Some bug fixes about timer and MMIO.
3. Some hardening about interrupt injection.
4. Replace kvm_err() with kvm_pr_unimpl().
5. Add FPU/LSX/LASX test cases for selftests.

Add FPU/LSX/LASX test cases and verify FPU register get and set APIs,
the FPU width supports 64/128/256 bits.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Add LSX and LASX features when VM is created. These features are detected
firstly, enable it if it is available on host machine.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

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>

Add and use KVM wrappers for pthread_{g,s}etaffinity_np() so that selftests
don't need to manually assert that the syscalls succeeded, and so that they
don't need to manually pass in sizeof(cpu_set_t) for the size.

Link: https://patch.msgid.link/20260731195612.2697986-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Deduplicate test code that does cancel()+join() on pthreads by adding a
collection of syscall wrappers.  The tests that asynchronously cancel
pthreads, i.e. use PTHREAD_CANCEL_ASYNCHRONOUS, are particularly ugly,
especially since it's not immediately obvious why those tests assert on
the thread being CANCELED, whereas others do not.

No functional change intended.

Link: https://patch.msgid.link/20260731195612.2697986-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Add and use KVM wrappers for pthread_{cancel,join}() so that selftests
don't need to manually assert that the syscalls succeeded.

Note, the vast majority tests don't actually assert success, but they all
obviously rely on the syscall to succeed.

Other than explicitly failing if a syscall fails, no functional change
intended.

Link: https://patch.msgid.link/20260731195612.2697986-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>