Commit 91a0b547 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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KVM: selftests: Test that values written to Hyper-V MSRs are preserved 



Enhance 'hyperv_features' selftest by adding a check that KVM
preserves values written to PV MSRs. Two MSRs are, however, 'special':
- HV_X64_MSR_EOI as it is a 'write-only' MSR,
- HV_X64_MSR_RESET as it always reads as '0'.
The later doesn't require any special handling right now because the
test never writes anything besides '0' to the MSR, leave a TODO node
about the fact.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20221013095849.705943-7-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 2f10428a

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

+28 −8
Original line number Diff line number Diff line
@@ -34,22 +34,36 @@ struct hcall_data { 
	bool ud_expected;

};



static bool is_write_only_msr(uint32_t msr)

{

	return msr == HV_X64_MSR_EOI;

}



static void guest_msr(struct msr_data *msr)

{

	uint64_t ignored;

	uint8_t vector;

	uint8_t vector = 0;

	uint64_t msr_val = 0;



	GUEST_ASSERT(msr->idx);



	if (!msr->write)

		vector = rdmsr_safe(msr->idx, &ignored);

	else

	if (msr->write)

		vector = wrmsr_safe(msr->idx, msr->write_val);



	if (!vector && (!msr->write || !is_write_only_msr(msr->idx)))

		vector = rdmsr_safe(msr->idx, &msr_val);



	if (msr->fault_expected)

		GUEST_ASSERT_2(vector == GP_VECTOR, msr->idx, vector);

		GUEST_ASSERT_3(vector == GP_VECTOR, msr->idx, vector, GP_VECTOR);

	else

		GUEST_ASSERT_2(!vector, msr->idx, vector);

		GUEST_ASSERT_3(!vector, msr->idx, vector, 0);



	if (vector || is_write_only_msr(msr->idx))

		goto done;



	if (msr->write)

		GUEST_ASSERT_3(msr_val == msr->write_val, msr->idx,

			       msr_val, msr->write_val);

done:

	GUEST_DONE();

}
@@ -239,6 +253,12 @@ static void guest_test_msrs_access(void) 
		case 16:

			msr->idx = HV_X64_MSR_RESET;

			msr->write = true;

			/*

			 * TODO: the test only writes '0' to HV_X64_MSR_RESET

			 * at the moment, writing some other value there will

			 * trigger real vCPU reset and the code is not prepared

			 * to handle it yet.

			 */

			msr->write_val = 0;

			msr->fault_expected = false;

			break;
@@ -433,7 +453,7 @@ static void guest_test_msrs_access(void) 


		switch (get_ucall(vcpu, &uc)) {

		case UCALL_ABORT:

			REPORT_GUEST_ASSERT_2(uc, "MSR = %lx, vector = %lx");

			REPORT_GUEST_ASSERT_3(uc, "MSR = %lx, arg1 = %lx, arg2 = %lx");

			return;

		case UCALL_DONE:

			break;