If SGX runtime launch control is enabled on host (IA32_FEATURE_CONTROL[17]
is set), KVM can support running multiple guests with each running LE signed
with different RSA pubkey. KVM traps IA32_SGXLEPUBKEYHASHn MSR write from
and keeps the values to vcpu internally, and when vcpu is scheduled in, KVM
write those values to real IA32_SGXLEPUBKEYHASHn MSR.
Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 5 ++
arch/x86/kvm/vmx.c | 123 +++++++++++++++++++++++++++++++++++++++
2 files changed, 128 insertions(+)
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index e3770f570bb9..70482b951b0f 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -417,6 +417,11 @@
#define MSR_IA32_TSC_ADJUST 0x0000003b
#define MSR_IA32_BNDCFGS 0x00000d90
+#define MSR_IA32_SGXLEPUBKEYHASH0 0x0000008c
+#define MSR_IA32_SGXLEPUBKEYHASH1 0x0000008d
+#define MSR_IA32_SGXLEPUBKEYHASH2 0x0000008e
+#define MSR_IA32_SGXLEPUBKEYHASH3 0x0000008f
+
#define MSR_IA32_XSS 0x00000da0
#define FEATURE_CONTROL_LOCKED (1<<0)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a16539594a99..c96332b9dd44 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -656,6 +656,9 @@ struct vcpu_vmx {
*/
u64 msr_ia32_feature_control;
u64 msr_ia32_feature_control_valid_bits;
+
+ /* SGX Launch Control public key hash */
+ u64 msr_ia32_sgxlepubkeyhash[4];
};
enum segment_cache_field {
@@ -2244,6 +2247,70 @@ static void decache_tsc_multiplier(struct vcpu_vmx *vmx)
vmcs_write64(TSC_MULTIPLIER, vmx->current_tsc_ratio);
}
+static bool cpu_sgx_lepubkeyhash_writable(void)
+{
+ u64 val, sgx_lc_enabled_mask = (FEATURE_CONTROL_LOCKED |
+ FEATURE_CONTROL_SGX_LAUNCH_CONTROL_ENABLE);
+
+ rdmsrl(MSR_IA32_FEATURE_CONTROL, val);
+
+ return ((val & sgx_lc_enabled_mask) == sgx_lc_enabled_mask);
+}
+
+static bool vmx_sgx_lc_disabled_in_bios(struct kvm_vcpu *vcpu)
+{
+ return (to_vmx(vcpu)->msr_ia32_feature_control & FEATURE_CONTROL_LOCKED)
+ && (!(to_vmx(vcpu)->msr_ia32_feature_control &
+ FEATURE_CONTROL_SGX_LAUNCH_CONTROL_ENABLE));
+}
+
+#define SGX_INTEL_DEFAULT_LEPUBKEYHASH0 0xa6053e051270b7ac
+#define SGX_INTEL_DEFAULT_LEPUBKEYHASH1 0x6cfbe8ba8b3b413d
+#define SGX_INTEL_DEFAULT_LEPUBKEYHASH2 0xc4916d99f2b3735d
+#define SGX_INTEL_DEFAULT_LEPUBKEYHASH3 0xd4f8c05909f9bb3b
+
+static void vmx_sgx_init_lepubkeyhash(struct kvm_vcpu *vcpu)
+{
+ u64 h0, h1, h2, h3;
+
+ /*
+ * If runtime launch control is enabled (IA32_SGXLEPUBKEYHASHn is
+ * writable), we set guest's default value to be Intel's default
+ * hash (which is fixed value and can be hard-coded). Otherwise,
+ * guest can only use machine's IA32_SGXLEPUBKEYHASHn so set guest's
+ * default to that.
+ */
+ if (cpu_sgx_lepubkeyhash_writable()) {
+ h0 = SGX_INTEL_DEFAULT_LEPUBKEYHASH0;
+ h1 = SGX_INTEL_DEFAULT_LEPUBKEYHASH1;
+ h2 = SGX_INTEL_DEFAULT_LEPUBKEYHASH2;
+ h3 = SGX_INTEL_DEFAULT_LEPUBKEYHASH3;
+ }
+ else {
+ rdmsrl(MSR_IA32_SGXLEPUBKEYHASH0, h0);
+ rdmsrl(MSR_IA32_SGXLEPUBKEYHASH1, h1);
+ rdmsrl(MSR_IA32_SGXLEPUBKEYHASH2, h2);
+ rdmsrl(MSR_IA32_SGXLEPUBKEYHASH3, h3);
+ }
+
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[0] = h0;
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[1] = h1;
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[2] = h2;
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[3] = h3;
+}
+
+static void vmx_sgx_lepubkeyhash_load(struct kvm_vcpu *vcpu)
+{
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0,
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[0]);
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH1,
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[1]);
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH2,
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[2]);
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH3,
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[3]);
+}
+
/*
* Switches to specified vcpu, until a matching vcpu_put(), but assumes
* vcpu mutex is already taken.
@@ -2316,6 +2383,14 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
vmx_vcpu_pi_load(vcpu, cpu);
vmx->host_pkru = read_pkru();
+
+ /*
+ * Load guset's SGX LE pubkey hash if runtime launch control is
+ * enabled.
+ */
+ if (guest_cpuid_has_sgx_launch_control(vcpu) &&
+ cpu_sgx_lepubkeyhash_writable())
+ vmx_sgx_lepubkeyhash_load(vcpu);
}
static void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu)
@@ -3225,6 +3300,19 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_FEATURE_CONTROL:
msr_info->data = to_vmx(vcpu)->msr_ia32_feature_control;
break;
+ case MSR_IA32_SGXLEPUBKEYHASH0 ... MSR_IA32_SGXLEPUBKEYHASH3:
+ /*
+ * SDM 35.1 Model-Specific Registers, table 35-2.
+ * Read permitted if CPUID.0x12.0:EAX[0] = 1. (We have
+ * guaranteed this will be true if guest_cpuid_has_sgx
+ * is true.)
+ */
+ if (!guest_cpuid_has_sgx(vcpu))
+ return 1;
+ msr_info->data =
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[msr_info->index -
+ MSR_IA32_SGXLEPUBKEYHASH0];
+ break;
case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
if (!nested_vmx_allowed(vcpu))
return 1;
@@ -3344,6 +3432,37 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
* SGX has been enabled in BIOS before using SGX.
*/
break;
+ case MSR_IA32_SGXLEPUBKEYHASH0 ... MSR_IA32_SGXLEPUBKEYHASH3:
+ /*
+ * SDM 35.1 Model-Specific Registers, table 35-2.
+ * - If CPUID.0x7.0:ECX[30] = 1, FEATURE_CONTROL[17] is
+ * available.
+ * - Write permitted if CPUID.0x12.0:EAX[0] = 1 &&
+ * FEATURE_CONTROL[17] = 1 && FEATURE_CONTROL[0] = 1.
+ */
+ if (!guest_cpuid_has_sgx(vcpu) ||
+ !guest_cpuid_has_sgx_launch_control(vcpu))
+ return 1;
+ /*
+ * Don't let userspace set guest's IA32_SGXLEPUBKEYHASHn,
+ * if machine's IA32_SGXLEPUBKEYHASHn cannot be changed at
+ * runtime. Note to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash are
+ * set to default in vmx_create_vcpu therefore guest is able
+ * to get the machine's IA32_SGXLEPUBKEYHASHn by rdmsr in
+ * guest.
+ */
+ if (!cpu_sgx_lepubkeyhash_writable())
+ return 1;
+ /*
+ * If guest's FEATURE_CONTROL[17] is not set, guest's
+ * IA32_SGXLEPUBKEYHASHn are not writeable from guest.
+ */
+ if (!vmx_sgx_lc_disabled_in_bios(vcpu) &&
+ !msr_info->host_initiated)
+ return 1;
+ to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash[msr_index -
+ MSR_IA32_SGXLEPUBKEYHASH0] = data;
+ break;
case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
if (!msr_info->host_initiated)
return 1; /* they are read-only */
@@ -9305,6 +9424,10 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
vmx->nested.vpid02 = allocate_vpid();
}
+ /* Set vcpu's default IA32_SGXLEPUBKEYHASHn */
+ if (enable_sgx && boot_cpu_has(X86_FEATURE_SGX_LAUNCH_CONTROL))
+ vmx_sgx_init_lepubkeyhash(&vmx->vcpu);
+
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
vmx->nested.current_vmcs12 = NULL;
--
2.11.0
