KVM/riscv fixes for 6.10, take #2

- Fix compilation for KVM selftests

Due to commit 2b7deea3ec7c ("Revert "kvm: selftests: move base
kvm_util.h declarations to kvm_util_base.h"") kvm selftests now
requires explicitly including ucall_common.h when needed. The commit
added the directives everywhere they were needed at the time, but, by
merge time, new places had been merged for RISC-V. Add those now to
fix RISC-V's compilation.

Fixes: dee7ea42a1eb ("Merge tag 'kvm-x86-selftests_utils-6.10' of https://github.com/kvm-x86/linux into HEAD")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240603122045.323064-2-ajones@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>

Use the max mappable GPA via GuestPhysBits advertised by KVM to calculate
max_gfn. Currently some selftests (e.g. access_tracking_perf_test,
dirty_log_test...) add RAM regions close to max_gfn, so guest may access
GPA beyond its mappable range and cause infinite loop.

Adjust max_gfn in vm_compute_max_gfn() since x86 selftests already
overrides vm_compute_max_gfn() specifically to deal with goofy edge cases.

Reported-by: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20240513014003.104593-1-tao1.su@linux.intel.com
[sean: tweak name, add comment and sanity check]
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM selftests treewide updates for 6.10:

 - Define _GNU_SOURCE for all selftests to fix a warning that was introduced by
   a change to kselftest_harness.h late in the 6.9 cycle, and because forcing
   every test to #define _GNU_SOURCE is painful.

 - Provide a global psuedo-RNG instance for all tests, so that library code can
   generate random, but determinstic numbers.

 - Use the global pRNG to randomly force emulation of select writes from guest
   code on x86, e.g. to help validate KVM's emulation of locked accesses.

 - Rename kvm_util_base.h back to kvm_util.h, as the weird layer of indirection
   was added purely to avoid manually #including ucall_common.h in a handful of
   locations.

 - Allocate and initialize x86's GDT, IDT, TSS, segments, and default exception
   handlers at VM creation, instead of forcing tests to manually trigger the
   related setup.

KVM selftests cleanups and fixes for 6.10:

 - Enhance the demand paging test to allow for better reporting and stressing
   of UFFD performance.

 - Convert the steal time test to generate TAP-friendly output.

 - Fix a flaky false positive in the xen_shinfo_test due to comparing elapsed
   time across two different clock domains.

 - Skip the MONITOR/MWAIT test if the host doesn't actually support MWAIT.

 - Avoid unnecessary use of "sudo" in the NX hugepage test to play nice with
   running in a minimal userspace environment.

 - Allow skipping the RSEQ test's sanity check that the vCPU was able to
   complete a reasonable number of KVM_RUNs, as the assert can fail on a
   completely valid setup.  If the test is run on a large-ish system that is
   otherwise idle, and the test isn't affined to a low-ish number of CPUs, the
   vCPU task can be repeatedly migrated to CPUs that are in deep sleep states,
   which results in the vCPU having very little net runtime before the next
   migration due to high wakeup latencies.

KVM/arm64 updates for Linux 6.10

- Move a lot of state that was previously stored on a per vcpu
  basis into a per-CPU area, because it is only pertinent to the
  host while the vcpu is loaded. This results in better state
  tracking, and a smaller vcpu structure.

- Add full handling of the ERET/ERETAA/ERETAB instructions in
  nested virtualisation. The last two instructions also require
  emulating part of the pointer authentication extension.
  As a result, the trap handling of pointer authentication has
  been greattly simplified.

- Turn the global (and not very scalable) LPI translation cache
  into a per-ITS, scalable cache, making non directly injected
  LPIs much cheaper to make visible to the vcpu.

- A batch of pKVM patches, mostly fixes and cleanups, as the
  upstreaming process seems to be resuming. Fingers crossed!

- Allocate PPIs and SGIs outside of the vcpu structure, allowing
  for smaller EL2 mapping and some flexibility in implementing
  more or less than 32 private IRQs.

- Purge stale mpidr_data if a vcpu is created after the MPIDR
  map has been created.

- Preserve vcpu-specific ID registers across a vcpu reset.

- Various minor cleanups and improvements.

 KVM/riscv changes for 6.10

- Support guest breakpoints using ebreak
- Introduce per-VCPU mp_state_lock and reset_cntx_lock
- Virtualize SBI PMU snapshot and counter overflow interrupts
- New selftests for SBI PMU and Guest ebreak

Explicitly require KVM_CAP_USER_MEMORY2 for selftests that create memslots,
i.e. skip selftests that need memslots instead of letting them fail on
KVM_SET_USER_MEMORY_REGION2.  While it's ok to take a dependency on new
kernel features, selftests should skip gracefully instead of failing hard
when run on older kernels.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/69ae0694-8ca3-402c-b864-99b500b24f5d@moroto.mountain
Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240430162133.337541-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Drop the @selector from the kernel code, data, and TSS builders and
instead hardcode the respective selector in the helper.  Accepting a
selector but not a base makes the selector useless, e.g. the data helper
can't create per-vCPU for FS or GS, and so loading GS with KERNEL_DS is
the only logical choice.

And for code and TSS, there is no known reason to ever want multiple
segments, e.g. there are zero plans to support 32-bit kernel code (and
again, that would require more than just the selector).

If KVM selftests ever do add support for per-vCPU segments, it'd arguably
be more readable to add a dedicated helper for building/setting the
per-vCPU segment, and move the common data segment code to an inner
helper.

Lastly, hardcoding the selector reduces the probability of setting the
wrong selector in the vCPU versus what was created by the VM in the GDT.

Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Initialize x86's various segments in the GDT during creation of relevant
VMs instead of waiting until vCPUs come along.  Re-installing the segments
for every vCPU is both wasteful and confusing, as is installing KERNEL_DS
multiple times; NOT installing KERNEL_DS for GS is icing on the cake.

Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-18-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>