From d8589154363f10ce15bedfc1bd4c6cb2a002d33d Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 13 Oct 2022 11:58:48 +0200 Subject: [PATCH] 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: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Reviewed-by: Sean Christopherson Message-Id: <20221013095849.705943-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- .../testing/selftests/kvm/x86_64/hyperv_features.c | 36 +++++++++++++++++----- 1 file changed, 28 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_features.c b/tools/testing/selftests/kvm/x86_64/hyperv_features.c index daad3e3..b002409 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_features.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_features.c @@ -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; -- 2.7.4