x86/access: Add forced emulation support

Add support to force access tests to be handled by the emulator, if
supported by KVM. Due to emulation being rather slow, make the forced
emulation nodefaul

x86/access: Add forced emulation support

Add support to force access tests to be handled by the emulator, if
supported by KVM. Due to emulation being rather slow, make the forced
emulation nodefault, i.e. a manual-only testcase. Note, "manual" just
means the test runner needs to specify a specific group(s), i.e. the
test is still easy to enable in CI for compatible setups.

Manually check for FEP support in the test instead of using the "check"
option to query the module param, as any non-zero force_emulation_prefix
value enables FEP (see KVM commit d500e1ed3dc8 ("KVM: x86: Allow clearing
RFLAGS.RF on forced emulation to test code #DBs") and scripts/runtime.bash
only supports checking for a single value.

Defer enabling FEP for the nested VMX variants to a future patch. KVM has
a bug related to emulating NOP (yes, NOP) for L2, and the nVMX varaints
will require additional massaging to propagate the "allow emulation" flag.

Signed-off-by: Mathias Krause <minipli@grsecurity.net>
[sean: make generic fep testcase nodefault instead of impossible]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230404165341.163500-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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x86/access: Use standard pass/fail reporting machinery

Use the standard reporting machinery in the access test so that future
changes to skip variants of the test actually get reported as SKIPs.

Si

x86/access: Use standard pass/fail reporting machinery

Use the standard reporting machinery in the access test so that future
changes to skip variants of the test actually get reported as SKIPs.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230404165341.163500-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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x86: Clean up the global, page_table_levels, in access.c

Remove the global, page table levels, from access.c and store it in the
test struct ac_test_t instead.

Signed-off-by: Aaron Lewis <aaronlewi

x86: Clean up the global, page_table_levels, in access.c

Remove the global, page table levels, from access.c and store it in the
test struct ac_test_t instead.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20211110212001.3745914-14-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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x86: Prepare access test for running in L2

Move main out of access.c in preparation for running the test in L2.
This allows access.c to be used as common code that will be
included in a nested tests

x86: Prepare access test for running in L2

Move main out of access.c in preparation for running the test in L2.
This allows access.c to be used as common code that will be
included in a nested tests later in this series.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20211110212001.3745914-12-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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