The revamp of monitor/mwait test missed the original check of feature
availability [*]. If MONITOR/MWAIT is not supported or is disabled by
IA32_MISC_ENABLE on the host, executing MONITOR or MWAIT instruction
from guest doesn't cause monitor/mwait VM exits, but a #UD.

[*] https://lore.kernel.org/all/20240411210237.34646-1-zide.chen@intel.com/

Reported-by: Xuelian Guo <xuelian.guo@intel.com>
Fixes: 80fd663590cf ("selftests: kvm: revamp MONITOR/MWAIT tests")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Link: https://lore.kernel.org/r/20250620062219.342930-1-chenyi.qiang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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.

Add a test case to verify x86's bus lock exit functionality, which is now
supported on both Intel and AMD.  Trigger bus lock exits by performing a
split-lock access, i.e. an atomic access that splits two cache lines.

Verify that the correct number of bus lock exits are generated, and that
the counter is incremented correctly and at the appropriate time based on
the underlying architecture.

Generate bus locks in both L1 and L2 (if nested virtualization is enabled),
as SVM's functionality in particular requires non-trivial logic to do the
right thing when running nested VMs.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Co-developed-by: Manali Shukla <manali.shukla@amd.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20250502050346.14274-6-manali.shukla@amd.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>

Add a test to verify KVM's fastops emulation via forced emulation.  KVM's
so called "fastop" infrastructure executes the to-be-emulated instruction
directly on hardware instead of manually emulating the instruction in
software, using various shenanigans to glue together the emulator context
and CPU state, e.g. to get RFLAGS fed into the instruction and back out
for the emulator.

Add testcases for all instructions that are low hanging fruit.  While the
primary goal of the selftest is to validate the glue code, a secondary
goal is to ensure "emulation" matches hardware exactly, including for
arithmetic flags that are architecturally undefined.  While arithmetic
flags may be *architecturally* undefined, their behavior is deterministic
for a given CPU (likely a given uarch, and possibly even an entire family
or class of CPUs).  I.e. KVM has effectively been emulating underlying
hardware behavior for years.

Link: https://lore.kernel.org/r/20250506011250.1089254-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Extend sev_smoke_test to also run a minimal SEV-SNP smoke test that
initializes and sets up private memory regions required to run a simple
SEV-SNP guest.

Similar to its SEV-ES smoke test counterpart, this also does not
support GHCB and ucall yet and uses the GHCB MSR protocol to trigger an
exit of the type KVM_EXIT_SYSTEM_EVENT.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-11-prsampat@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

In preparation for SNP, cleanup the smoke test to decouple deriving type
from policy.  This will allow reusing the existing interfaces for SNP.

No functional change intended.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-10-prsampat@amd.com
[sean: massage shortlog+changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>

In preparation for SNP, declutter the vm type check by introducing a
SEV-SNP VM type check as well as a transitive set of helper functions.

The SNP VM type is the subset of SEV-ES. Similarly, the SEV-ES and SNP
types are subset of the SEV VM type check.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-7-prsampat@amd.com
[sean: make the helpers static inlines]
Signed-off-by: Sean Christopherson <seanjc@google.com>

Move the SMT control check out of the hyperv_cpuid selftest so that it
is generally accessible all KVM selftests. Split the functionality into
a helper that populates a buffer with SMT control value which other
helpers can use to ascertain if SMT state is available and active.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-5-prsampat@amd.com
[sean: prepend is_ to the helpers]
Signed-off-by: Sean Christopherson <seanjc@google.com>

Abstract rep vmmcall coded into the vmgexit helper for the sev
library.

No functional change intended.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-4-prsampat@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Add the X86_FEATURE_SEV_SNP CPU feature to the architectural definition
for the SEV-SNP VM type to exercise the KVM_SEV_INIT2 call. Ensure that
the SNP test is skipped in scenarios where CPUID supports it but KVM
does not, preventing reporting of failure in such cases.

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-3-prsampat@amd.com
[sean: use the same pattern as SEV and SEV-ES]
Signed-off-by: Sean Christopherson <seanjc@google.com>