[PATCH v2 00/30] KVM: x86: hyper-v: Fine-grained access check to Hyper-V hypercalls and MSRs

From: Vitaly Kuznetsov
Date: Fri May 21 2021 - 05:52:17 EST


Changes since v1:
- Rebase to kvm/next.

Original description:

Currently, all implemented Hyper-V features (MSRs and hypercalls) are
available unconditionally to all Hyper-V enabled guests. This is not
ideal as KVM userspace may decide to provide only a subset of the
currently implemented features to emulate an older Hyper-V version,
to reduce attack surface,... Implement checks against guest visible
CPUIDs for all currently implemented MSRs and hypercalls.

Vitaly Kuznetsov (30):
asm-generic/hyperv: add HV_STATUS_ACCESS_DENIED definition
KVM: x86: hyper-v: Introduce KVM_CAP_HYPERV_ENFORCE_CPUID
KVM: x86: hyper-v: Cache guest CPUID leaves determining features
availability
KVM: x86: hyper-v: Prepare to check access to Hyper-V MSRs
KVM: x86: hyper-v: Honor HV_MSR_HYPERCALL_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_VP_RUNTIME_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_TIME_REF_COUNT_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_VP_INDEX_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_RESET_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_REFERENCE_TSC_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_SYNIC_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_SYNTIMER_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_MSR_APIC_ACCESS_AVAILABLE privilege bit
KVM: x86: hyper-v: Honor HV_ACCESS_FREQUENCY_MSRS privilege bit
KVM: x86: hyper-v: Honor HV_ACCESS_REENLIGHTENMENT privilege bit
KVM: x86: hyper-v: Honor HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE
privilege bit
KVM: x86: hyper-v: Honor HV_FEATURE_DEBUG_MSRS_AVAILABLE privilege bit
KVM: x86: hyper-v: Inverse the default in hv_check_msr_access()
KVM: x86: hyper-v: Honor HV_STIMER_DIRECT_MODE_AVAILABLE privilege bit
KVM: x86: hyper-v: Prepare to check access to Hyper-V hypercalls
KVM: x86: hyper-v: Check access to HVCALL_NOTIFY_LONG_SPIN_WAIT
hypercall
KVM: x86: hyper-v: Honor HV_POST_MESSAGES privilege bit
KVM: x86: hyper-v: Honor HV_SIGNAL_EVENTS privilege bit
KVM: x86: hyper-v: Honor HV_DEBUGGING privilege bit
KVM: x86: hyper-v: Honor HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED bit
KVM: x86: hyper-v: Honor HV_X64_CLUSTER_IPI_RECOMMENDED bit
KVM: x86: hyper-v: Honor HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED bit
KVM: selftests: move Hyper-V MSR definitions to hyperv.h
KVM: selftests: Move evmcs.h to x86_64/
KVM: selftests: Introduce hyperv_features test

Documentation/virt/kvm/api.rst | 11 +
arch/x86/include/asm/kvm_host.h | 9 +
arch/x86/kvm/hyperv.c | 216 +++++-
arch/x86/kvm/hyperv.h | 1 +
arch/x86/kvm/x86.c | 4 +
include/asm-generic/hyperv-tlfs.h | 1 +
include/uapi/linux/kvm.h | 1 +
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/include/{ => x86_64}/evmcs.h | 2 +-
.../selftests/kvm/include/x86_64/hyperv.h | 185 +++++
.../selftests/kvm/x86_64/hyperv_clock.c | 8 +-
.../selftests/kvm/x86_64/hyperv_features.c | 649 ++++++++++++++++++
13 files changed, 1071 insertions(+), 18 deletions(-)
rename tools/testing/selftests/kvm/include/{ => x86_64}/evmcs.h (99%)
create mode 100644 tools/testing/selftests/kvm/include/x86_64/hyperv.h
create mode 100644 tools/testing/selftests/kvm/x86_64/hyperv_features.c

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2.31.1