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KVM: selftests: Rework platform_info_test to actually verify #GP

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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>
This commit is contained in:
Sean Christopherson
2024-03-14 16:26:25 -07:00
parent 53635ec253
commit dec79eab2b
1 changed files with 33 additions and 33 deletions
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66
tools/testing/selftests/kvm/x86_64/platform_info_test.c
View File

@@ -24,40 +24,18 @@
static void guest_code(void)
{
uint64_t msr_platform_info;
uint8_t vector;
for (;;) {
msr_platform_info = rdmsr(MSR_PLATFORM_INFO);
GUEST_ASSERT_EQ(msr_platform_info & MSR_PLATFORM_INFO_MAX_TURBO_RATIO,
MSR_PLATFORM_INFO_MAX_TURBO_RATIO);
GUEST_SYNC(0);
asm volatile ("inc %r11");
}
}
GUEST_SYNC(true);
msr_platform_info = rdmsr(MSR_PLATFORM_INFO);
GUEST_ASSERT_EQ(msr_platform_info & MSR_PLATFORM_INFO_MAX_TURBO_RATIO,
MSR_PLATFORM_INFO_MAX_TURBO_RATIO);
static void test_msr_platform_info_enabled(struct kvm_vcpu *vcpu)
{
struct ucall uc;
GUEST_SYNC(false);
vector = rdmsr_safe(MSR_PLATFORM_INFO, &msr_platform_info);
GUEST_ASSERT_EQ(vector, GP_VECTOR);
vm_enable_cap(vcpu->vm, KVM_CAP_MSR_PLATFORM_INFO, true);
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_SYNC:
break;
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
default:
TEST_FAIL("Unexpected ucall %lu", uc.cmd);
break;
}
}
static void test_msr_platform_info_disabled(struct kvm_vcpu *vcpu)
{
vm_enable_cap(vcpu->vm, KVM_CAP_MSR_PLATFORM_INFO, false);
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_SHUTDOWN);
GUEST_DONE();
}
int main(int argc, char *argv[])
@@ -65,16 +43,38 @@ int main(int argc, char *argv[])
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
uint64_t msr_platform_info;
struct ucall uc;
TEST_REQUIRE(kvm_has_cap(KVM_CAP_MSR_PLATFORM_INFO));
vm = vm_create_with_one_vcpu(&vcpu, guest_code);
vm_init_descriptor_tables(vm);
vcpu_init_descriptor_tables(vcpu);
msr_platform_info = vcpu_get_msr(vcpu, MSR_PLATFORM_INFO);
vcpu_set_msr(vcpu, MSR_PLATFORM_INFO,
msr_platform_info | MSR_PLATFORM_INFO_MAX_TURBO_RATIO);
test_msr_platform_info_enabled(vcpu);
test_msr_platform_info_disabled(vcpu);
for (;;) {
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_SYNC:
vm_enable_cap(vm, KVM_CAP_MSR_PLATFORM_INFO, uc.args[1]);
break;
case UCALL_DONE:
goto done;
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
default:
TEST_FAIL("Unexpected ucall %lu", uc.cmd);
break;
}
}
done:
vcpu_set_msr(vcpu, MSR_PLATFORM_INFO, msr_platform_info);
kvm_vm_free(vm);