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KVM: selftests: Test that values written to Hyper-V MSRs are preserved

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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 <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013095849.705943-7-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2022-10-13 11:58:48 +02:00 committed by Paolo Bonzini
parent 2f10428ace
commit 91a0b5478a
1 changed files with 28 additions and 8 deletions
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36
tools/testing/selftests/kvm/x86_64/hyperv_features.c
View File

@ -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;