From: Kai Huang <kai.huang@intel.com>
To: kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, seanjc@google.com,
jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com,
rick.p.edgecombe@intel.com, haitao.huang@intel.com,
pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com, jmattson@google.com,
joro@8bytes.org, vkuznets@redhat.com, wanpengli@tencent.com,
corbet@lwn.net, Andy Lutomirski <luto@amacapital.net>,
Kai Huang <kai.huang@intel.com>
Subject: [PATCH v2 25/25] KVM: x86: Add capability to grant VM access to privileged SGX attribute
Date: Tue, 9 Mar 2021 14:41:36 +1300 [thread overview]
Message-ID: <2e6472d7944c7f51e0c5fb0261a3a180fe2e03cc.1615250634.git.kai.huang@intel.com> (raw)
In-Reply-To: <cover.1615250634.git.kai.huang@intel.com>
From: Sean Christopherson <sean.j.christopherson@intel.com>
Add a capability, KVM_CAP_SGX_ATTRIBUTE, that can be used by userspace
to grant a VM access to a priveleged attribute, with args[0] holding a
file handle to a valid SGX attribute file.
The SGX subsystem restricts access to a subset of enclave attributes to
provide additional security for an uncompromised kernel, e.g. to prevent
malware from using the PROVISIONKEY to ensure its nodes are running
inside a geniune SGX enclave and/or to obtain a stable fingerprint.
To prevent userspace from circumventing such restrictions by running an
enclave in a VM, KVM restricts guest access to privileged attributes by
default.
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
Documentation/virt/kvm/api.rst | 23 +++++++++++++++++++++++
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/x86.c | 21 +++++++++++++++++++++
include/uapi/linux/kvm.h | 1 +
4 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 1a2b5210cdbf..614f150e6c15 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6227,6 +6227,29 @@ KVM_RUN_BUS_LOCK flag is used to distinguish between them.
This capability can be used to check / enable 2nd DAWR feature provided
by POWER10 processor.
+7.24 KVM_CAP_SGX_ATTRIBUTE
+----------------------
+
+:Architectures: x86
+:Target: VM
+:Parameters: args[0] is a file handle of a SGX attribute file in securityfs
+:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested
+ attribute is not supported by KVM.
+
+KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or
+more priveleged enclave attributes. args[0] must hold a file handle to a valid
+SGX attribute file corresponding to an attribute that is supported/restricted
+by KVM (currently only PROVISIONKEY).
+
+The SGX subsystem restricts access to a subset of enclave attributes to provide
+additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY
+is restricted to deter malware from using the PROVISIONKEY to obtain a stable
+system fingerprint. To prevent userspace from circumventing such restrictions
+by running an enclave in a VM, KVM prevents access to privileged attributes by
+default.
+
+See Documentation/x86/sgx/2.Kernel-internals.rst for more details.
+
8. Other capabilities.
======================
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a0d45607b702..6dc12d949f86 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -849,7 +849,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
* expected to derive it from supported XCR0.
*/
entry->eax &= SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT |
- /* PROVISIONKEY | */ SGX_ATTR_EINITTOKENKEY |
+ SGX_ATTR_PROVISIONKEY | SGX_ATTR_EINITTOKENKEY |
SGX_ATTR_KSS;
entry->ebx &= 0;
break;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5233e3ad69ee..ec243ce7c27a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -75,6 +75,7 @@
#include <asm/tlbflush.h>
#include <asm/intel_pt.h>
#include <asm/emulate_prefix.h>
+#include <asm/sgx.h>
#include <clocksource/hyperv_timer.h>
#define CREATE_TRACE_POINTS
@@ -3759,6 +3760,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_X86_USER_SPACE_MSR:
case KVM_CAP_X86_MSR_FILTER:
case KVM_CAP_ENFORCE_PV_FEATURE_CPUID:
+#ifdef CONFIG_X86_SGX_KVM
+ case KVM_CAP_SGX_ATTRIBUTE:
+#endif
r = 1;
break;
#ifdef CONFIG_KVM_XEN
@@ -5345,6 +5349,23 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
kvm->arch.bus_lock_detection_enabled = true;
r = 0;
break;
+#ifdef CONFIG_X86_SGX_KVM
+ case KVM_CAP_SGX_ATTRIBUTE: {
+ unsigned long allowed_attributes = 0;
+
+ r = sgx_set_attribute(&allowed_attributes, cap->args[0]);
+ if (r)
+ break;
+
+ /* KVM only supports the PROVISIONKEY privileged attribute. */
+ if ((allowed_attributes & SGX_ATTR_PROVISIONKEY) &&
+ !(allowed_attributes & ~SGX_ATTR_PROVISIONKEY))
+ kvm->arch.sgx_provisioning_allowed = true;
+ else
+ r = -EINVAL;
+ break;
+ }
+#endif
default:
r = -EINVAL;
break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index f6afee209620..7d8927e474f8 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1078,6 +1078,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_DIRTY_LOG_RING 192
#define KVM_CAP_X86_BUS_LOCK_EXIT 193
#define KVM_CAP_PPC_DAWR1 194
+#define KVM_CAP_SGX_ATTRIBUTE 195
#ifdef KVM_CAP_IRQ_ROUTING
--
2.29.2
next prev parent reply other threads:[~2021-03-09 1:42 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 1:38 [PATCH v2 00/25] KVM SGX virtualization support Kai Huang
2021-03-09 1:38 ` [PATCH v2 01/25] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-03-12 21:05 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 02/25] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-03-12 21:10 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-03-10 9:35 ` Kai Huang
2021-03-11 2:01 ` [PATCH v3 " Kai Huang
2021-03-12 21:21 ` Sean Christopherson
2021-03-13 10:45 ` Jarkko Sakkinen
2021-03-15 7:12 ` Kai Huang
2021-03-15 13:18 ` Jarkko Sakkinen
2021-03-15 13:19 ` Jarkko Sakkinen
2021-03-15 20:29 ` Kai Huang
2021-03-15 22:59 ` Jarkko Sakkinen
2021-03-15 23:50 ` Kai Huang
2021-03-15 23:11 ` Jarkko Sakkinen
2021-03-09 1:39 ` [PATCH v2 04/25] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-03-09 1:39 ` [PATCH v2 05/25] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-03-09 1:39 ` [PATCH v2 06/25] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-03-12 21:33 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 07/25] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-03-12 21:44 ` Sean Christopherson
2021-03-13 19:05 ` Jarkko Sakkinen
2021-03-13 19:07 ` Jarkko Sakkinen
2021-03-14 15:25 ` Jarkko Sakkinen
2021-03-14 15:27 ` Jarkko Sakkinen
2021-03-15 3:13 ` Kai Huang
2021-03-15 13:04 ` Jarkko Sakkinen
2021-03-15 13:51 ` Jarkko Sakkinen
2021-03-15 20:48 ` Kai Huang
2021-03-15 23:05 ` Jarkko Sakkinen
2021-03-15 23:08 ` Jarkko Sakkinen
2021-03-15 23:49 ` Kai Huang
2021-03-16 12:44 ` Jarkko Sakkinen
2021-03-16 1:13 ` Sean Christopherson
2021-03-16 12:46 ` Jarkko Sakkinen
2021-03-18 0:04 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 08/25] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-03-12 21:58 ` Sean Christopherson
2021-03-15 3:36 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 09/25] x86/sgx: Move ENCLS leaf definitions to sgx.h Kai Huang
2021-03-09 1:39 ` [PATCH v2 10/25] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-03-09 1:39 ` [PATCH v2 11/25] x86/sgx: Add encls_faulted() helper Kai Huang
2021-03-09 1:39 ` [PATCH v2 12/25] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-03-09 1:39 ` [PATCH v2 13/25] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-03-15 4:08 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 14/25] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-03-09 1:40 ` [PATCH v2 15/25] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-03-09 1:40 ` [PATCH v2 16/25] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-03-09 1:40 ` [PATCH v2 17/25] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-03-09 1:40 ` [PATCH v2 18/25] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-03-09 1:40 ` [PATCH v2 19/25] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-03-09 1:40 ` [PATCH v2 20/25] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-03-09 1:40 ` [PATCH v2 21/25] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-03-09 1:40 ` [PATCH v2 22/25] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-03-09 1:40 ` [PATCH v2 23/25] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-03-09 1:40 ` [PATCH v2 24/25] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-03-09 1:41 ` Kai Huang [this message]
2021-03-09 9:30 ` [PATCH v2 00/25] KVM SGX virtualization support Borislav Petkov
2021-03-09 18:08 ` Kai Huang
2021-03-09 18:49 ` Paolo Bonzini
2021-03-12 22:04 ` Sean Christopherson
2021-03-13 4:30 ` Kai Huang
2021-03-10 9:27 ` Kai Huang
2021-03-10 13:29 ` Borislav Petkov
2021-03-11 2:05 ` Kai Huang
2021-03-10 18:01 ` Jarkko Sakkinen
2021-03-10 20:44 ` Kai Huang
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