| Message ID | 20220110060445.549800-2-shirong@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Allow guest to query AMD SEV(-ES) runtime attestation evidence | expand |
On Mon, Jan 10, 2022, Shirong Hao wrote: > This hypercall is used by the SEV guest to get the firmware handle. This is completely insufficient to justify why KVM is providing host information to the guest, let alone why KVM is providing that information to guest _userspace_. > +static int sev_vm_handle(struct kvm *kvm) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + > + if (!sev_guest(kvm)) > + return -ENOTTY; > + > + return sev->handle; > +} > + > static struct kvm_x86_ops svm_x86_ops __initdata = { > .name = "kvm_amd", > ... > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 0cf1082455df..24acf0f2a539 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -8906,7 +8906,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > a3 &= 0xFFFFFFFF; > } > > - if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { > + if (static_call(kvm_x86_get_cpl)(vcpu) != 0 && nr != KVM_HC_VM_HANDLE) { > ret = -KVM_EPERM; > goto out; > }
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2164b9f4c7b0..fe745f4e6954 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1493,6 +1493,7 @@ struct kvm_x86_ops { int (*complete_emulated_msr)(struct kvm_vcpu *vcpu, int err); void (*vcpu_deliver_sipi_vector)(struct kvm_vcpu *vcpu, u8 vector); + int (*vm_handle)(struct kvm *kvm); }; struct kvm_x86_nested_ops { diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d0f68d11ec70..c0eb310cb4c3 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4576,6 +4576,16 @@ static int svm_vm_init(struct kvm *kvm) return 0; } +static int sev_vm_handle(struct kvm *kvm) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + + if (!sev_guest(kvm)) + return -ENOTTY; + + return sev->handle; +} + static struct kvm_x86_ops svm_x86_ops __initdata = { .name = "kvm_amd", @@ -4705,6 +4715,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .complete_emulated_msr = svm_complete_emulated_msr, .vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector, + .vm_handle = sev_vm_handle, }; static struct kvm_x86_init_ops svm_init_ops __initdata = { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0cf1082455df..24acf0f2a539 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8906,7 +8906,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) a3 &= 0xFFFFFFFF; } - if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { + if (static_call(kvm_x86_get_cpl)(vcpu) != 0 && nr != KVM_HC_VM_HANDLE) { ret = -KVM_EPERM; goto out; } @@ -8965,6 +8965,11 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) vcpu->arch.complete_userspace_io = complete_hypercall_exit; return 0; } + case KVM_HC_VM_HANDLE: + ret = -KVM_ENOSYS; + if (kvm_x86_ops.vm_handle) + ret = kvm_x86_ops.vm_handle(vcpu->kvm); + break; default: ret = -KVM_ENOSYS; break; diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h index 960c7e93d1a9..b64469a12707 100644 --- a/include/uapi/linux/kvm_para.h +++ b/include/uapi/linux/kvm_para.h @@ -30,6 +30,7 @@ #define KVM_HC_SEND_IPI 10 #define KVM_HC_SCHED_YIELD 11 #define KVM_HC_MAP_GPA_RANGE 12 +#define KVM_HC_VM_HANDLE 13 /* * hypercalls use architecture specific
This hypercall is used by the SEV guest to get the firmware handle. Signed-off-by: Shirong Hao <shirong@linux.alibaba.com> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm/svm.c | 11 +++++++++++ arch/x86/kvm/x86.c | 7 ++++++- include/uapi/linux/kvm_para.h | 1 + 4 files changed, 19 insertions(+), 1 deletion(-)