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[PATCH 12/32] i386: Update SGX CPUID info according to hardware/KVM/user
From: |
Yang Zhong |
Subject: |
[PATCH 12/32] i386: Update SGX CPUID info according to hardware/KVM/user input |
Date: |
Mon, 19 Apr 2021 18:01:36 +0800 |
From: Sean Christopherson <sean.j.christopherson@intel.com>
Expose SGX to the guest if and only if KVM is enabled and supports
virtualization of SGX. While the majority of ENCLS can be emulated to
some degree, because SGX uses a hardware-based root of trust, the
attestation aspects of SGX cannot be emulated in software, i.e.
ultimately emulation will fail as software cannot generate a valid
quote/report. The complexity of partially emulating SGX in Qemu far
outweighs the value added, e.g. an SGX specific simulator for userspace
applications can emulate SGX for development and testing purposes.
Note, access to the PROVISIONKEY is not yet advertised to the guest as
KVM blocks access to the PROVISIONKEY by default and requires userspace
to provide additional credentials (via ioctl()) to expose PROVISIONKEY.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
hw/i386/sgx-epc.c | 17 +++++++++
include/hw/i386/sgx-epc.h | 2 +
target/i386/cpu.c | 77 +++++++++++++++++++++++++++++++++++++++
3 files changed, 96 insertions(+)
diff --git a/hw/i386/sgx-epc.c b/hw/i386/sgx-epc.c
index 0858819a71..d5ba7bb68c 100644
--- a/hw/i386/sgx-epc.c
+++ b/hw/i386/sgx-epc.c
@@ -173,6 +173,23 @@ static void sgx_epc_register_types(void)
type_init(sgx_epc_register_types)
+int sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
+{
+ PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
+ SGXEPCDevice *epc;
+
+ if (pcms->sgx_epc == NULL || pcms->sgx_epc->nr_sections <= section_nr) {
+ return 1;
+ }
+
+ epc = pcms->sgx_epc->sections[section_nr];
+
+ *addr = epc->addr;
+ *size = memory_device_get_region_size(MEMORY_DEVICE(epc), &error_fatal);
+
+ return 0;
+}
+
static int sgx_epc_set_property(void *opaque, const char *name,
const char *value, Error **errp)
diff --git a/include/hw/i386/sgx-epc.h b/include/hw/i386/sgx-epc.h
index 1f7dd17c17..8d80b34fb7 100644
--- a/include/hw/i386/sgx-epc.h
+++ b/include/hw/i386/sgx-epc.h
@@ -57,4 +57,6 @@ typedef struct SGXEPCState {
extern int sgx_epc_enabled;
+int sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size);
+
#endif
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 43e6fdf162..e630e57f03 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -60,6 +60,7 @@
#include "exec/address-spaces.h"
#include "hw/i386/apic_internal.h"
#include "hw/boards.h"
+#include "hw/i386/sgx-epc.h"
#endif
#include "disas/capstone.h"
@@ -5807,6 +5808,25 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
uint32_t count,
*ecx |= CPUID_7_0_ECX_OSPKE;
}
*edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
+
+ /*
+ * SGX cannot be emulated in software. If hardware does not
+ * support enabling SGX and/or SGX flexible launch control,
+ * then we need to update the VM's CPUID values accordingly.
+ */
+ if ((*ebx & CPUID_7_0_EBX_SGX) &&
+ (!kvm_enabled() ||
+ !(kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7, 0, R_EBX) &
+ CPUID_7_0_EBX_SGX))) {
+ *ebx &= ~CPUID_7_0_EBX_SGX;
+ }
+
+ if ((*ecx & CPUID_7_0_ECX_SGX_LC) &&
+ (!(*ebx & CPUID_7_0_EBX_SGX) || !kvm_enabled() ||
+ !(kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7, 0, R_ECX) &
+ CPUID_7_0_ECX_SGX_LC))) {
+ *ecx &= ~CPUID_7_0_ECX_SGX_LC;
+ }
} else if (count == 1) {
*eax = env->features[FEAT_7_1_EAX];
*ebx = 0;
@@ -5942,6 +5962,63 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
uint32_t count,
}
break;
}
+ case 0x12:
+#ifndef CONFIG_USER_ONLY
+ if (!kvm_enabled() ||
+ !(env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_SGX)) {
+ *eax = *ebx = *ecx = *edx = 0;
+ break;
+ }
+
+ /*
+ * SGX sub-leafs CPUID.0x12.{0x2..N} enumerate EPC sections. Retrieve
+ * the EPC properties, e.g. confidentiality and integrity, from the
+ * host's first EPC section, i.e. assume there is one EPC section or
+ * that all EPC sections have the same security properties.
+ */
+ if (count > 1) {
+ uint64_t epc_addr, epc_size;
+
+ if (sgx_epc_get_section(count - 2, &epc_addr, &epc_size)) {
+ *eax = *ebx = *ecx = *edx = 0;
+ break;
+ }
+ host_cpuid(index, 2, eax, ebx, ecx, edx);
+ *eax = (uint32_t)(epc_addr & 0xfffff000) | 0x1;
+ *ebx = (uint32_t)(epc_addr >> 32);
+ *ecx = (uint32_t)(epc_size & 0xfffff000) | (*ecx & 0xf);
+ *edx = (uint32_t)(epc_size >> 32);
+ break;
+ }
+
+ /*
+ * SGX sub-leafs CPUID.0x12.{0x0,0x1} are heavily dependent on hardware
+ * and KVM, i.e. QEMU cannot emulate features to override what KVM
+ * supports. Features can be further restricted by userspace, but not
+ * made more permissive.
+ */
+ *eax = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x12, count, R_EAX);
+ *ebx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x12, count, R_EBX);
+ *ecx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x12, count, R_ECX);
+ *edx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x12, count, R_EDX);
+
+ if (count == 0) {
+ *eax &= env->features[FEAT_SGX_12_0_EAX];
+ *ebx &= env->features[FEAT_SGX_12_0_EBX];
+ } else {
+ *eax &= env->features[FEAT_SGX_12_1_EAX];
+ *ebx &= 0; /* ebx reserve */
+ *ecx &= env->features[FEAT_XSAVE_COMP_LO];
+ *edx &= env->features[FEAT_XSAVE_COMP_HI];
+
+ /* FP and SSE are always allowed regardless of XSAVE/XCR0. */
+ *ecx |= XSTATE_FP_MASK | XSTATE_SSE_MASK;
+
+ /* Access to PROVISIONKEY requires additional credentials. */
+ *eax &= ~(1U << 4);
+ }
+#endif
+ break;
case 0x14: {
/* Intel Processor Trace Enumeration */
*eax = 0;
--
2.29.2.334.gfaefdd61ec
- [PATCH 02/32] hostmem: Add hostmem-epc as a backend for SGX EPC, (continued)
- [PATCH 02/32] hostmem: Add hostmem-epc as a backend for SGX EPC, Yang Zhong, 2021/04/19
- [PATCH 01/32] memory: Add RAM_PROTECTED flag to skip IOMMU mappings, Yang Zhong, 2021/04/19
- [PATCH 03/32] qom: Add memory-backend-epc ObjectOptions support, Yang Zhong, 2021/04/19
- [PATCH 04/32] i386: Add 'sgx-epc' device to expose EPC sections to guest, Yang Zhong, 2021/04/19
- [PATCH 08/32] i386: Add SGX CPUID leaf FEAT_SGX_12_0_EBX, Yang Zhong, 2021/04/19
- [PATCH 06/32] i386: Add primary SGX CPUID and MSR defines, Yang Zhong, 2021/04/19
- [PATCH 05/32] vl: Add "sgx-epc" option to expose SGX EPC sections to guest, Yang Zhong, 2021/04/19
- [PATCH 09/32] i386: Add SGX CPUID leaf FEAT_SGX_12_1_EAX, Yang Zhong, 2021/04/19
- [PATCH 10/32] i386: Add get/set/migrate support for SGX_LEPUBKEYHASH MSRs, Yang Zhong, 2021/04/19
- [PATCH 07/32] i386: Add SGX CPUID leaf FEAT_SGX_12_0_EAX, Yang Zhong, 2021/04/19
- [PATCH 12/32] i386: Update SGX CPUID info according to hardware/KVM/user input,
Yang Zhong <=
- [PATCH 11/32] i386: Add feature control MSR dependency when SGX is enabled, Yang Zhong, 2021/04/19
- [PATCH 13/32] linux-headers: Add placeholder for KVM_CAP_SGX_ATTRIBUTE, Yang Zhong, 2021/04/19
- [PATCH 15/32] i386: Propagate SGX CPUID sub-leafs to KVM, Yang Zhong, 2021/04/19
- [PATCH 14/32] i386: kvm: Add support for exposing PROVISIONKEY to guest, Yang Zhong, 2021/04/19
- [PATCH 16/32] Adjust min CPUID level to 0x12 when SGX is enabled, Yang Zhong, 2021/04/19
- [PATCH 17/32] hw/i386/fw_cfg: Set SGX bits in feature control fw_cfg accordingly, Yang Zhong, 2021/04/19
- [PATCH 18/32] hw/i386/pc: Account for SGX EPC sections when calculating device memory, Yang Zhong, 2021/04/19
- [PATCH 19/32] i386/pc: Add e820 entry for SGX EPC section(s), Yang Zhong, 2021/04/19