Commit 8ad48552 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Sean Christopherson
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KVM: selftests: Avoid infinite loop in hyperv_features when invtsc is missing 



When X86_FEATURE_INVTSC is missing, guest_test_msrs_access() was supposed
to skip testing dependent Hyper-V invariant TSC feature. Unfortunately,
'continue' does not lead to that as stage is not incremented. Moreover,
'vm' allocated with vm_create_with_one_vcpu() is not freed and the test
runs out of available file descriptors very quickly.

Fixes: bd827bd7 ("KVM: selftests: Test Hyper-V invariant TSC control")
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240129085847.2674082-1-vkuznets@redhat.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 46fee9e3

tools/testing/selftests/kvm/x86_64/hyperv_features.c

+5 −4
Original line number Diff line number Diff line
@@ -454,7 +454,7 @@ static void guest_test_msrs_access(void) 
		case 44:

			/* MSR is not available when CPUID feature bit is unset */

			if (!has_invtsc)

				continue;

				goto next_stage;

			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;

			msr->write = false;

			msr->fault_expected = true;
@@ -462,7 +462,7 @@ static void guest_test_msrs_access(void) 
		case 45:

			/* MSR is vailable when CPUID feature bit is set */

			if (!has_invtsc)

				continue;

				goto next_stage;

			vcpu_set_cpuid_feature(vcpu, HV_ACCESS_TSC_INVARIANT);

			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;

			msr->write = false;
@@ -471,7 +471,7 @@ static void guest_test_msrs_access(void) 
		case 46:

			/* Writing bits other than 0 is forbidden */

			if (!has_invtsc)

				continue;

				goto next_stage;

			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;

			msr->write = true;

			msr->write_val = 0xdeadbeef;
@@ -480,7 +480,7 @@ static void guest_test_msrs_access(void) 
		case 47:

			/* Setting bit 0 enables the feature */

			if (!has_invtsc)

				continue;

				goto next_stage;

			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;

			msr->write = true;

			msr->write_val = 1;
@@ -513,6 +513,7 @@ static void guest_test_msrs_access(void) 
			return;

		}



next_stage:

		stage++;

		kvm_vm_free(vm);

	}