diff options
| author | Oliver Upton <oupton@google.com> | 2020-08-18 15:24:28 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-10-21 17:36:32 -0400 |
| commit | 66570e966dd9cb4fd57811d0056c6472a14a2c41 (patch) | |
| tree | 06172486c1b55c545ea71bc0cd23c288c7b19fd1 /arch/x86/include | |
| parent | 210dfd93ea3dc63e8c21b75ddd909447341f6382 (diff) | |
kvm: x86: only provide PV features if enabled in guest's CPUID
KVM unconditionally provides PV features to the guest, regardless of the
configured CPUID. An unwitting guest that doesn't check
KVM_CPUID_FEATURES before use could access paravirt features that
userspace did not intend to provide. Fix this by checking the guest's
CPUID before performing any paravirtual operations.
Introduce a capability, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, to gate the
aforementioned enforcement. Migrating a VM from a host w/o this patch to
a host with this patch could silently change the ABI exposed to the
guest, warranting that we default to the old behavior and opt-in for
the new one.
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Change-Id: I202a0926f65035b872bfe8ad15307c026de59a98
Message-Id: <20200818152429.1923996-4-oupton@google.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d0f77235da92..15e51343957e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -789,6 +789,21 @@ struct kvm_vcpu_arch { /* AMD MSRC001_0015 Hardware Configuration */ u64 msr_hwcr; + + /* pv related cpuid info */ + struct { + /* + * value of the eax register in the KVM_CPUID_FEATURES CPUID + * leaf. + */ + u32 features; + + /* + * indicates whether pv emulation should be disabled if features + * are not present in the guest's cpuid + */ + bool enforce; + } pv_cpuid; }; struct kvm_lpage_info { |