diff options
| author | Xiaoyao Li <xiaoyao.li@intel.com> | 2020-07-08 08:50:47 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-07-08 22:22:00 +0200 |
| commit | 18964092825aef6faaadf51fbc5fd166168ddf61 (patch) | |
| tree | 8b0118b1786e00c40ce05a0cb3a48e11d2a984c9 | |
| parent | kvm: x86: limit the maximum number of vPMU fixed counters to 3 (diff) | |
| download | linux-18964092825aef6faaadf51fbc5fd166168ddf61.tar.xz linux-18964092825aef6faaadf51fbc5fd166168ddf61.zip | |
KVM: X86: Reset vcpu->arch.cpuid_nent to 0 if SET_CPUID* fails
Current implementation keeps userspace input of CPUID configuration and
cpuid->nent even if kvm_update_cpuid() fails. Reset vcpu->arch.cpuid_nent
to 0 for the case of failure as a simple fix.
Besides, update the doc to explicitly state that if IOCTL SET_CPUID*
fail KVM gives no gurantee that previous valid CPUID configuration is
kept.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200708065054.19713-2-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 1cfe79b932d6..644e5326aa50 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -669,6 +669,10 @@ MSRs that have been set successfully. Defines the vcpu responses to the cpuid instruction. Applications should use the KVM_SET_CPUID2 ioctl if available. +Note, when this IOCTL fails, KVM gives no guarantees that previous valid CPUID +configuration (if there is) is not corrupted. Userspace can get a copy of the +resulting CPUID configuration through KVM_GET_CPUID2 in case. + :: struct kvm_cpuid_entry { diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 6f2b6e9c9ae0..b7bbed0de636 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -209,6 +209,8 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, kvm_apic_set_version(vcpu); kvm_x86_ops.cpuid_update(vcpu); r = kvm_update_cpuid(vcpu); + if (r) + vcpu->arch.cpuid_nent = 0; kvfree(cpuid_entries); out: @@ -232,6 +234,8 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, kvm_apic_set_version(vcpu); kvm_x86_ops.cpuid_update(vcpu); r = kvm_update_cpuid(vcpu); + if (r) + vcpu->arch.cpuid_nent = 0; out: return r; } |