[PATCH 24/42] KVM: selftests: Add and use helper to set vCPU's CPUID maxphyaddr

From: Sean Christopherson
Date: Fri Jun 03 2022 - 21:23:06 EST


Add a helper to set a vCPU's guest.MAXPHYADDR, and use it in the test
that verifies the emulator returns an error on an unknown instruction
when KVM emulates in response to an EPT violation with a GPA that is
legal in hardware but illegal with respect to the guest's MAXPHYADDR.

Add a helper even though there's only a single user at this time. Before
its removal, mmu_role_test also stuffed guest.MAXPHYADDR, and the helper
provides a small amount of clarity.

More importantly, this eliminates a set_cpuid() user and an instance of
modifying kvm_get_supported_cpuid()'s static "cpuid".

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/x86_64/processor.h | 2 ++
tools/testing/selftests/kvm/lib/x86_64/processor.c | 8 ++++++++
.../testing/selftests/kvm/x86_64/emulator_error_test.c | 10 +---------
3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 61b8047243e0..d6ffd625513b 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -656,6 +656,8 @@ static inline void vcpu_set_cpuid(struct kvm_vcpu *vcpu)
vcpu_ioctl(vcpu, KVM_GET_CPUID2, vcpu->cpuid);
}

+void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr);
+
void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu,
struct kvm_x86_cpu_feature feature,
bool set);
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 5383ccdeb8e2..06ae7542f2c9 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -763,6 +763,14 @@ void vcpu_init_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid)
vcpu_set_cpuid(vcpu);
}

+void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr)
+{
+ struct kvm_cpuid_entry2 *entry = vcpu_get_cpuid_entry(vcpu, 0x80000008);
+
+ entry->eax = (entry->eax & ~0xff) | maxphyaddr;
+ vcpu_set_cpuid(vcpu);
+}
+
void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu,
struct kvm_x86_cpu_feature feature,
bool set)
diff --git a/tools/testing/selftests/kvm/x86_64/emulator_error_test.c b/tools/testing/selftests/kvm/x86_64/emulator_error_test.c
index bb410c359599..9d08ccdf6604 100644
--- a/tools/testing/selftests/kvm/x86_64/emulator_error_test.c
+++ b/tools/testing/selftests/kvm/x86_64/emulator_error_test.c
@@ -151,8 +151,6 @@ static uint64_t process_ucall(struct kvm_vcpu *vcpu)

int main(int argc, char *argv[])
{
- struct kvm_cpuid_entry2 *entry;
- struct kvm_cpuid2 *cpuid;
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
uint64_t gpa, pte;
@@ -166,13 +164,7 @@ int main(int argc, char *argv[])

vm = vm_create_with_one_vcpu(&vcpu, guest_code);

- cpuid = kvm_get_supported_cpuid();
-
- entry = kvm_get_supported_cpuid_index(0x80000008, 0);
- entry->eax = (entry->eax & 0xffffff00) | MAXPHYADDR;
- set_cpuid(cpuid, entry);
-
- vcpu_init_cpuid(vcpu, cpuid);
+ vcpu_set_cpuid_maxphyaddr(vcpu, MAXPHYADDR);

rc = kvm_check_cap(KVM_CAP_EXIT_ON_EMULATION_FAILURE);
TEST_ASSERT(rc, "KVM_CAP_EXIT_ON_EMULATION_FAILURE is unavailable");
--
2.36.1.255.ge46751e96f-goog