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>
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>
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>
There is already an ASSERT_EQ macro in the file
tools/testing/selftests/kselftest_harness.h, so currently KVM selftests
can't include test_util.h from the KVM selftests together with that file.
Rename the macro in the KVM selftests to TEST_ASSERT_EQ to avoid the
problem - it is also more similar to the other macros in test_util.h that
way.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20230712075910.22480-2-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a sub-test to verify that KVM stuffs the APIC_ID when userspace forces
a transition from x2APIC to xAPIC without first disabling the APIC. Such
a transition is architecturally disallowed (WRMSR will #GP), but needs to
be handled by KVM to allow userspace to emulate RESET (ignoring that
userspace should also stuff local APIC state on RESET).
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Link: https://lore.kernel.org/r/20230109130605.2013555-3-eesposit@redhat.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Cache a vCPU's CPUID information in "struct kvm_vcpu" to allow fixing the
mess where tests, often unknowingly, modify the global/static "cpuid"
allocated by kvm_get_supported_cpuid().
Add vcpu_init_cpuid() to handle stuffing an entirely different CPUID
model, e.g. during vCPU creation or when switching to the Hyper-V enabled
CPUID model. Automatically refresh the cache on vcpu_set_cpuid() so that
any adjustments made by KVM are always reflected in the cache. Drop
vcpu_get_cpuid() entirely to force tests to use the cache, and to allow
adding e.g. vcpu_get_cpuid_entry() in the future without creating a
conflicting set of APIs where vcpu_get_cpuid() does KVM_GET_CPUID2, but
vcpu_get_cpuid_entry() does not.
Opportunistically convert the VMX nested state test and KVM PV test to
manipulating the vCPU's CPUID (because it's easy), but use
vcpu_init_cpuid() for the Hyper-V features test and "emulator error" test
to effectively retain their current behavior as they're less trivial to
convert.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-19-seanjc@google.com
Hardware would directly write x2APIC ICR register instead of software
emulation in some circumstances, e.g when Intel IPI virtualization is
enabled. This behavior requires normal reserved bits checking to ensure
them input as zero, otherwise it will cause #GP. So we need mask out
those reserved bits from the data written to vICR register.
Remove Delivery Status bit emulation in test case as this flag
is invalid and not needed in x2APIC mode. KVM may ignore clearing
it during interrupt dispatch which will lead to fake test failure.
Opportunistically correct vector number for test sending IPI to
non-existent vCPUs.
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Message-Id: <20220623094511.26066-1-guang.zeng@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Take a vCPU directly instead of a VM+vcpu pair in all vCPU-scoped helpers
and ioctls.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Convert xapic_state_test to use vm_create_with_one_vcpu() and pass around
a 'struct kvm_vcpu' object instead of the raw vCPU ID.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rename xapic_state_test's kvm_vcpu struct to xapic_vcpu to avoid a
collision when the common 'struct vcpu' is renamed to 'struct kvm_vcpu'
in a future patch.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The main thing that the selftest verifies is that KVM copies x2APIC's
ICR[63:32] to/from ICR2 when userspace accesses the vAPIC page via
KVM_{G,S}ET_LAPIC. KVM previously split x2APIC ICR to ICR+ICR2 at the
time of write (from the guest), and so KVM must preserve that behavior
for backwards compatibility between different versions of KVM.
It will also test other invariants, e.g. that KVM clears the BUSY
flag on ICR writes, that the reserved bits in ICR2 are dropped on writes
from the guest, etc...
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220204214205.3306634-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
