KVM selftests changes for 6.12:
- Fix a goof that caused some Hyper-V tests to be skipped when run on bare
metal, i.e. NOT in a VM.
- Add a regression test for KVM's handling of SHUTDOWN for an SEV-ES guest.
- Explicitly include one-off assets in .gitignore. Past Sean was completely
wrong about not being able to detect missing .gitignore entries.
- Verify userspace single-stepping works when KVM happens to handle a VM-Exit
in its fastpath.
- Misc cleanups
In x86's debug_regs test, change the RDMSR(MISC_ENABLES) in the single-step
testcase to a WRMSR(TSC_DEADLINE) in order to verify that KVM honors
KVM_GUESTDBG_SINGLESTEP when handling a fastpath VM-Exit.
Note, the extra coverage is effectively Intel-only, as KVM only handles
TSC_DEADLINE in the fastpath when the timer is emulated via the hypervisor
timer, a.k.a. the VMX preemption timer.
Link: https://lore.kernel.org/r/20240830044448.130449-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
When AVIC, and thus IPI virtualization on AMD, is enabled, the CPU will
virtualize ICR writes. Unfortunately, the CPU doesn't do a very good job,
as it fails to clear the BUSY bit and also allows writing ICR2[23:0],
despite them being "RESERVED MBZ". Account for the quirky behavior in
the xapic_state test to avoid failures in a configuration that likely has
no hope of ever being enabled in production.
Link: https://lore.kernel.org/r/20240719235107.3023592-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Now that the BUSY bit mess is gone (for x2APIC), verify that the *guest*
can read back the ICR value that it wrote. Due to the divergent
behavior between AMD and Intel with respect to the backing storage of the
ICR in the vAPIC page, emulating a seemingly simple MSR write is quite
complex.
Link: https://lore.kernel.org/r/20240719235107.3023592-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Actually test x2APIC ICR reserved bits instead of deliberately skipping
them. The behavior that is observed when IPI virtualization is enabled is
the architecturally correct behavior, KVM is the one who was wrong, i.e.
KVM was missing reserved bit checks.
Fixes: 4b88b1a518 ("KVM: selftests: Enhance handling WRMSR ICR register in x2APIC mode")
Link: https://lore.kernel.org/r/20240719235107.3023592-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Don't test the ICR BUSY bit when x2APIC is enabled as AMD and Intel have
different behavior (AMD #GPs, Intel ignores), and the fact that the CPU
performs the reserved bit checks when IPI virtualization is enabled makes
it impossible for KVM to precisely emulate one or the other.
Link: https://lore.kernel.org/r/20240719235107.3023592-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
KVM_CAP_HYPERV_DIRECT_TLBFLUSH is only reported when KVM runs on top of
Hyper-V and hyperv_evmcs/hyperv_svm_test don't need that, these tests check
that the feature is properly emulated for Hyper-V on KVM guests. There's no
corresponding CAP for that, the feature is reported in
KVM_GET_SUPPORTED_HV_CPUID.
Hyper-V specific CPUIDs are not reported by KVM_GET_SUPPORTED_CPUID,
implement dedicated kvm_hv_cpu_has() helper to do the job.
Fixes: 6dac119518 ("KVM: selftests: Make Hyper-V tests explicitly require KVM Hyper-V support")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240816130139.286246-3-vkuznets@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a test to verify that userspace can't change a vCPU's x2APIC ID by
abusing KVM_SET_LAPIC. KVM models the x2APIC ID (and x2APIC LDR) as
readonly, and silently ignores userspace attempts to change the x2APIC ID
for backwards compatibility.
Signed-off-by: Michal Luczaj <mhal@rbox.co>
[sean: write changelog, add to existing test]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240802202941.344889-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM selftests for 6.11
- Remove dead code in the memslot modification stress test.
- Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs.
- Print the guest pseudo-RNG seed only when it changes, to avoid spamming the
log for tests that create lots of VMs.
- Make the PMU counters test less flaky when counting LLC cache misses by
doing CLFLUSH{OPT} in every loop iteration.
KVM x86 misc changes for 6.11
- Add a global struct to consolidate tracking of host values, e.g. EFER, and
move "shadow_phys_bits" into the structure as "maxphyaddr".
- Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC
bus frequency, because TDX.
- Print the name of the APICv/AVIC inhibits in the relevant tracepoint.
- Clean up KVM's handling of vendor specific emulation to consistently act on
"compatible with Intel/AMD", versus checking for a specific vendor.
- Misc cleanups
KVM generic changes for 6.11
- Enable halt poll shrinking by default, as Intel found it to be a clear win.
- Setup empty IRQ routing when creating a VM to avoid having to synchronize
SRCU when creating a split IRQCHIP on x86.
- Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
that arch code can use for hooking both sched_in() and sched_out().
- Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
truncating a bogus value from userspace, e.g. to help userspace detect bugs.
- Mark a vCPU as preempted if and only if it's scheduled out while in the
KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
memory when retrieving guest state during live migration blackout.
- A few minor cleanups
Currently the PMU counters test does a single CLFLUSH{,OPT} on the loop's
code, but due to speculative execution this might not cause LLC misses
within the measured section.
Instead of doing a single flush before the loop, do a cache flush on each
iteration of the loop to confuse the prediction and ensure that at least
one cache miss occurs within the measured section.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
[sean: keep MFENCE, massage changelog]
Link: https://lore.kernel.org/r/20240628005558.3835480-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
The KVM_CREATE_VCPU ioctl ABI had an implicit integer truncation bug,
allowing 2^32 aliases for a vCPU ID by setting the upper 32 bits of a 64
bit ioctl() argument.
It also allowed excluding a once set boot CPU ID.
Verify this no longer works and gets rejected with an error.
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240614202859.3597745-5-minipli@grsecurity.net
[sean: tweak assert message+comment for 63:32!=0 testcase]
Signed-off-by: Sean Christopherson <seanjc@google.com>
When detecting AMD PMU support for encoding "branch instructions retired"
as event 0xc2,0, simply check for Family 17h+ as all Zen CPUs support said
encoding, and AMD will maintain the encoding for backwards compatibility
on future CPUs.
Note, the kernel proper also interprets Family 17h+ as Zen (see the sole
caller of init_amd_zen_common()).
Suggested-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20240605050835.30491-1-manali.shukla@amd.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Currrentl a 32 bit 1u value is being shifted more than 32 bits causing
overflow and incorrect checking of bits 32-63. Fix this by using the
BIT_ULL macro for shifting bits.
Detected by cppcheck:
sev_init2_tests.c:108:34: error: Shifting 32-bit value by 63 bits is
undefined behaviour [shiftTooManyBits]
Fixes: dfc083a181 ("selftests: kvm: add tests for KVM_SEV_INIT2")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20240523154102.2236133-1-colin.i.king@gmail.com
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.
Initialize the IDT and exception handlers for all non-barebones VMs and
vCPUs on x86. Forcing tests to manually configure the IDT just to save
8KiB of memory is a terrible tradeoff, and also leads to weird tests
(multiple tests have deliberately relied on shutdown to indicate success),
and hard-to-debug failures, e.g. instead of a precise unexpected exception
failure, tests see only shutdown.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Rework platform_info_test to actually handle and verify the expected #GP
on RDMSR when the associated KVM capability is disabled. Currently, the
test _deliberately_ doesn't handle the #GP, and instead lets it escalated
to a triple fault shutdown.
In addition to verifying that KVM generates the correct fault, handling
the #GP will be necessary (without even more shenanigans) when a future
change to the core KVM selftests library configures the IDT and exception
handlers by default (the test subtly relies on the IDT limit being '0').
Link: https://lore.kernel.org/r/20240314232637.2538648-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
As a first step toward gracefully handling the expected #GP on RDMSR in
platform_info_test, move the test's assert on the non-faulting RDMSR
result into the guest itself. This will allow using a unified flow for
the host userspace side of things.
Link: https://lore.kernel.org/r/20240314232637.2538648-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Effectively revert the movement of code from kvm_util.h => kvm_util_base.h,
as the TL;DR of the justification for the move was to avoid #idefs and/or
circular dependencies between what ended up being ucall_common.h and what
was (and now again, is), kvm_util.h.
But avoiding #ifdef and circular includes is trivial: don't do that. The
cost of removing kvm_util_base.h is a few extra includes of ucall_common.h,
but that cost is practically nothing. On the other hand, having a "base"
version of a header that is really just the header itself is confusing,
and makes it weird/hard to choose names for headers that actually are
"base" headers, e.g. to hold core KVM selftests typedefs.
For all intents and purposes, this reverts commit
7d9a662ed9.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Introduce a macro, vcpu_arch_put_guest(), for "putting" values to memory
from guest code in "interesting" situations, e.g. when writing memory that
is being dirty logged. Structure the macro so that arch code can provide
a custom implementation, e.g. x86 will use the macro to force emulation of
the access.
Use the helper in dirty_log_test, which is of particular interest (see
above), and in xen_shinfo_test, which isn't all that interesting, but
provides a second usage of the macro with a different size operand
(uint8_t versus uint64_t), i.e. to help verify that the macro works for
more than just 64-bit values.
Use "put" as the verb to align with the kernel's {get,put}_user()
terminology.
Link: https://lore.kernel.org/r/20240314185459.2439072-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a global snapshot of kvm_is_forced_emulation_enabled() and sync it to
all VMs by default so that core library code can force emulation, e.g. to
allow for easier testing of the intersections between emulation and other
features in KVM.
Link: https://lore.kernel.org/r/20240314185459.2439072-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to
manually #define _GNU_SOURCE, which is repetitive and error prone. E.g.
kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest
includes kvm_test_harness.h after stdio.h, the include guards result in
the effective version of stdio.h consumed by kvm_test_harness.h not
defining asprintf():
In file included from x86_64/fix_hypercall_test.c:12:
In file included from include/kvm_test_harness.h:11:
../kselftest_harness.h:1169:2: error: call to undeclared function
'asprintf'; ISO C99 and later do not support implicit function declarations
[-Wimplicit-function-declaration]
1169 | asprintf(&test_name, "%s%s%s.%s", f->name,
| ^
When including the rseq selftest's "library" code, #undef _GNU_SOURCE so
that rseq.c controls whether or not it wants to build with _GNU_SOURCE.
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
If this feature is not supported or is disabled by IA32_MISC_ENABLE on
the host, executing MONITOR or MWAIT instruction from the guest doesn't
cause monitor/mwait VM exits, but a #UD.
So, we need to skip this test if CPUID.01H:ECX[3] is cleared.
Signed-off-by: Zide Chen <zide.chen@intel.com>
Link: https://lore.kernel.org/r/20240411210237.34646-1-zide.chen@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
xen_shinfo_test is observed to be flaky failing sporadically with
"VM time too old". With min_ts/max_ts debug print added:
Wall clock (v 3269818) 1704906491.986255664
Time info 1: v 1282712 tsc 33530585736 time 14014430025 mul 3587552223 shift 4294967295 flags 1
Time info 2: v 1282712 tsc 33530585736 time 14014430025 mul 3587552223 shift 4294967295 flags 1
min_ts: 1704906491.986312153
max_ts: 1704906506.001006963
==== Test Assertion Failure ====
x86_64/xen_shinfo_test.c:1003: cmp_timespec(&min_ts, &vm_ts) <= 0
pid=32724 tid=32724 errno=4 - Interrupted system call
1 0x00000000004030ad: main at xen_shinfo_test.c:1003
2 0x00007fca6b23feaf: ?? ??:0
3 0x00007fca6b23ff5f: ?? ??:0
4 0x0000000000405e04: _start at ??:?
VM time too old
The test compares wall clock data from shinfo (which is the output of
kvm_get_wall_clock_epoch()) against clock_gettime(CLOCK_REALTIME) in the
host system before the VM is created. In the example above, it compares
shinfo: 1704906491.986255664 vs min_ts: 1704906491.986312153
and fails as the later is greater than the former. While this sounds like
a sane test, it doesn't pass reality check: kvm_get_wall_clock_epoch()
calculates guest's epoch (realtime when the guest was created) by
subtracting kvmclock from the current realtime and the calculation happens
when shinfo is setup. The problem is that kvmclock is a raw clock and
realtime clock is affected by NTP. This means that if realtime ticks with a
slightly reduced frequency, "guest's epoch" calculated by
kvm_get_wall_clock_epoch() will actually tick backwards! This is not a big
issue from guest's perspective as the guest can't really observe this but
this epoch can't be compared with a fixed clock_gettime() on the host.
Replace the check with comparing wall clock data from shinfo to
KVM_GET_CLOCK. The later gives both realtime and kvmclock so guest's epoch
can be calculated by subtraction. Note, CLOCK_REALTIME is susceptible to
leap seconds jumps but there's no better alternative in KVM at this
moment. Leave a comment and accept 1s delta.
Reported-by: Jan Richter <jarichte@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240206151950.31174-1-vkuznets@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Extend vmx_dirty_log_test to include accesses made by L2 when EPT is
disabled.
This commit adds explicit coverage of a bug caught by syzkaller, where
the TDP MMU would clear D-bits instead of write-protecting SPTEs being
used to map an L2, which only happens when L1 does not enable EPT,
causing writes made by L2 to not be reflected in the dirty log when PML
is enabled:
$ ./vmx_dirty_log_test
Nested EPT: disabled
==== Test Assertion Failure ====
x86_64/vmx_dirty_log_test.c:151: test_bit(0, bmap)
pid=72052 tid=72052 errno=4 - Interrupted system call
(stack trace empty)
Page 0 incorrectly reported clean
Opportunistically replace the volatile casts with {READ,WRITE}_ONCE().
Link: https://lore.kernel.org/kvm/000000000000c6526f06137f18cc@google.com/
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240315230541.1635322-5-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Allow the caller to set the initial state of the VM. Doing this
before sev_vm_launch() matters for SEV-ES, since that is the
place where the VMSA is updated and after which the guest state
becomes sealed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240404121327.3107131-17-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a guest assert in the PMU counters test to verify that KVM stuffs
the vCPU's post-RESET value to globally enable all general purpose
counters. Per Intel's SDM,
IA32_PERF_GLOBAL_CTRL: Sets bits n-1:0 and clears the upper bits.
and
Where "n" is the number of general-purpose counters available in
the processor.
For the edge case where there are zero GP counters, follow the spirit
of the architecture, not the SDM's literal wording, which doesn't account
for this possibility and would require the CPU to set _all_ bits in
PERF_GLOBAL_CTRL.
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20240309013641.1413400-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Fix a bug in KVM_SET_CPUID{2,} where KVM looks at the wrong CPUID entries (old
vs. new) and ultimately neglects to clear PV_UNHALT from vCPUs with HLT-exiting
disabled.
KVM Xen and pfncache changes for 6.9:
- Rip out the half-baked support for using gfn_to_pfn caches to manage pages
that are "mapped" into guests via physical addresses.
- Add support for using gfn_to_pfn caches with only a host virtual address,
i.e. to bypass the "gfn" stage of the cache. The primary use case is
overlay pages, where the guest may change the gfn used to reference the
overlay page, but the backing hva+pfn remains the same.
- Add an ioctl() to allow mapping Xen's shared_info page using an hva instead
of a gpa, so that userspace doesn't need to reconfigure and invalidate the
cache/mapping if the guest changes the gpa (but userspace keeps the resolved
hva the same).
- When possible, use a single host TSC value when computing the deadline for
Xen timers in order to improve the accuracy of the timer emulation.
- Inject pending upcall events when the vCPU software-enables its APIC to fix
a bug where an upcall can be lost (and to follow Xen's behavior).
- Fall back to the slow path instead of warning if "fast" IRQ delivery of Xen
events fails, e.g. if the guest has aliased xAPIC IDs.
- Extend gfn_to_pfn_cache's mutex to cover (de)activation (in addition to
refresh), and drop a now-redundant acquisition of xen_lock (that was
protecting the shared_info cache) to fix a deadlock due to recursively
acquiring xen_lock.
KVM x86 PMU changes for 6.9:
- Fix several bugs where KVM speciously prevents the guest from utilizing
fixed counters and architectural event encodings based on whether or not
guest CPUID reports support for the _architectural_ encoding.
- Fix a variety of bugs in KVM's emulation of RDPMC, e.g. for "fast" reads,
priority of VMX interception vs #GP, PMC types in architectural PMUs, etc.
- Add a selftest to verify KVM correctly emulates RDMPC, counter availability,
and a variety of other PMC-related behaviors that depend on guest CPUID,
i.e. are difficult to validate via KVM-Unit-Tests.
- Zero out PMU metadata on AMD if the virtual PMU is disabled to avoid wasting
cycles, e.g. when checking if a PMC event needs to be synthesized when
skipping an instruction.
- Optimize triggering of emulated events, e.g. for "count instructions" events
when skipping an instruction, which yields a ~10% performance improvement in
VM-Exit microbenchmarks when a vPMU is exposed to the guest.
- Tighten the check for "PMI in guest" to reduce false positives if an NMI
arrives in the host while KVM is handling an IRQ VM-Exit.
KVM selftests changes for 6.9:
- Add macros to reduce the amount of boilerplate code needed to write "simple"
selftests, and to utilize selftest TAP infrastructure, which is especially
beneficial for KVM selftests with multiple testcases.
- Add basic smoke tests for SEV and SEV-ES, along with a pile of library
support for handling private/encrypted/protected memory.
- Fix benign bugs where tests neglect to close() guest_memfd files.
KVM_FEATURE_PV_UNHALT is expected to get cleared from KVM PV feature CPUID
data when KVM_X86_DISABLE_EXITS_HLT is enabled. Add the corresponding test
to kvm_pv_test.
Note, the newly added code doesn't actually test KVM_FEATURE_PV_UNHALT and
KVM_X86_DISABLE_EXITS_HLT features.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240228101837.93642-4-vkuznets@redhat.com
[sean: add and use vcpu_cpuid_has()]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Explicitly close() guest_memfd files in various guest_memfd and
private_mem_conversions tests, there's no reason to keep the files open
until the test exits.
Fixes: 8a89efd434 ("KVM: selftests: Add basic selftest for guest_memfd()")
Fixes: 43f623f350 ("KVM: selftests: Add x86-only selftest for private memory conversions")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Link: https://lore.kernel.org/r/20240227015716.27284-1-dongli.zhang@oracle.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Extend sev_smoke_test to also run a minimal SEV-ES smoke test so that it's
possible to test KVM's unique VMRUN=>#VMEXIT path for SEV-ES guests
without needing a full blown SEV-ES capable VM, which requires a rather
absurd amount of properly configured collateral.
Punt on proper GHCB and ucall support, and instead use the GHCB MSR
protocol to signal test completion. The most important thing at this
point is to have _any_ kind of testing of KVM's __svm_sev_es_vcpu_run().
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Carlos Bilbao <carlos.bilbao@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
