[Qemu-devel][PATCH v5 4/4] x86/cpu: Add user space access interface for CET MSRs

[Yang Weijiang <weijiang.yang@intel.com>]

Added interface for CET MSR_IA32_{U,S}_CET, MSR_IA32_PL{0,1,2,3}_SSP,
MSR_IA32_INTR_SSP_TBL and MSR_KVM_GUEST_SSP save/restore. Check if
corresponding CET features are available before access the MSRs.

Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
 target/i386/cpu.h     |  18 +++++
 target/i386/kvm.c     |  73 +++++++++++++++++++
 target/i386/machine.c | 161 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 252 insertions(+)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index ed03cd1760..51577a04ca 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -480,6 +480,15 @@ typedef enum X86Seg {
 #define MSR_IA32_VMX_TRUE_ENTRY_CTLS     0x00000490
 #define MSR_IA32_VMX_VMFUNC             0x00000491
 
+#define MSR_IA32_U_CET                  0x6a0
+#define MSR_IA32_S_CET                  0x6a2
+#define MSR_IA32_PL0_SSP                0x6a4
+#define MSR_IA32_PL1_SSP                0x6a5
+#define MSR_IA32_PL2_SSP                0x6a6
+#define MSR_IA32_PL3_SSP                0x6a7
+#define MSR_IA32_SSP_TBL                0x6a8
+#define MSR_KVM_GUEST_SSP               0x4b564d06
+
 #define XSTATE_FP_BIT                   0
 #define XSTATE_SSE_BIT                  1
 #define XSTATE_YMM_BIT                  2
@@ -1567,6 +1576,15 @@ typedef struct CPUX86State {
 
     uintptr_t retaddr;
 
+    uint64_t u_cet;
+    uint64_t s_cet;
+    uint64_t pl0_ssp;
+    uint64_t pl1_ssp;
+    uint64_t pl2_ssp;
+    uint64_t pl3_ssp;
+    uint64_t ssp_tbl;
+    uint64_t guest_ssp;
+
     /* Fields up to this point are cleared by a CPU reset */
     struct {} end_reset_fields;
 
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 4901c6dd74..0735981558 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -2979,6 +2979,31 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
         }
     }
 
+    if (((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) ||
+        (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_CET_IBT)) &&
+        (env->features[FEAT_XSAVES_LO] & XSTATE_CET_U_MASK)) {
+        kvm_msr_entry_add(cpu, MSR_IA32_U_CET, env->u_cet);
+        kvm_msr_entry_add(cpu, MSR_IA32_PL3_SSP, env->pl3_ssp);
+    }
+
+    if (env->features[FEAT_XSAVES_LO] & XSTATE_CET_S_MASK) {
+        if (env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) {
+            kvm_msr_entry_add(cpu, MSR_IA32_PL0_SSP, env->pl0_ssp);
+            kvm_msr_entry_add(cpu, MSR_IA32_PL1_SSP, env->pl1_ssp);
+            kvm_msr_entry_add(cpu, MSR_IA32_PL2_SSP, env->pl2_ssp);
+            kvm_msr_entry_add(cpu, MSR_IA32_SSP_TBL, env->ssp_tbl);
+        }
+
+        if (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_CET_IBT) {
+            kvm_msr_entry_add(cpu, MSR_IA32_S_CET, env->s_cet);
+        }
+    }
+
+    if ((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) &&
+        (env->features[FEAT_XSAVES_LO] & (XSTATE_CET_U_MASK |
+        XSTATE_CET_S_MASK)))
+        kvm_msr_entry_add(cpu, MSR_KVM_GUEST_SSP, env->guest_ssp);
+
     return kvm_buf_set_msrs(cpu);
 }
 
@@ -3295,6 +3320,30 @@ static int kvm_get_msrs(X86CPU *cpu)
         }
     }
 
+    if (((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) ||
+        (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_CET_IBT)) &&
+        (env->features[FEAT_XSAVES_LO] & XSTATE_CET_U_MASK)) {
+        kvm_msr_entry_add(cpu, MSR_IA32_U_CET, 0);
+        kvm_msr_entry_add(cpu, MSR_IA32_PL3_SSP, 0);
+    }
+
+    if (env->features[FEAT_XSAVES_LO] & XSTATE_CET_S_MASK) {
+        if (env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) {
+            kvm_msr_entry_add(cpu, MSR_IA32_PL0_SSP, 0);
+            kvm_msr_entry_add(cpu, MSR_IA32_PL1_SSP, 0);
+            kvm_msr_entry_add(cpu, MSR_IA32_PL2_SSP, 0);
+            kvm_msr_entry_add(cpu, MSR_IA32_SSP_TBL, 0);
+        }
+
+        if (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_CET_IBT) {
+            kvm_msr_entry_add(cpu, MSR_IA32_S_CET, 0);
+        }
+    }
+    if ((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK) &&
+        (env->features[FEAT_XSAVES_LO] & (XSTATE_CET_U_MASK |
+        XSTATE_CET_S_MASK)))
+        kvm_msr_entry_add(cpu, MSR_KVM_GUEST_SSP, 0);
+
     ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, cpu->kvm_msr_buf);
     if (ret < 0) {
         return ret;
@@ -3578,6 +3627,30 @@ static int kvm_get_msrs(X86CPU *cpu)
         case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B:
             env->msr_rtit_addrs[index - MSR_IA32_RTIT_ADDR0_A] = msrs[i].data;
             break;
+        case MSR_IA32_U_CET:
+            env->u_cet = msrs[i].data;
+            break;
+        case MSR_IA32_S_CET:
+            env->s_cet = msrs[i].data;
+            break;
+        case MSR_IA32_PL0_SSP:
+            env->pl0_ssp = msrs[i].data;
+            break;
+        case MSR_IA32_PL1_SSP:
+            env->pl1_ssp = msrs[i].data;
+            break;
+        case MSR_IA32_PL2_SSP:
+            env->pl2_ssp = msrs[i].data;
+            break;
+        case MSR_IA32_PL3_SSP:
+            env->pl3_ssp = msrs[i].data;
+            break;
+        case MSR_IA32_SSP_TBL:
+            env->ssp_tbl = msrs[i].data;
+            break;
+        case MSR_KVM_GUEST_SSP:
+            env->guest_ssp = msrs[i].data;
+            break;
         }
     }
 
diff --git a/target/i386/machine.c b/target/i386/machine.c
index 0c96531a56..3e1d8b6eb9 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -962,6 +962,159 @@ static const VMStateDescription vmstate_umwait = {
     }
 };
 
+static bool u_cet_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->u_cet != 0;
+}
+
+static const VMStateDescription vmstate_u_cet = {
+    .name = "cpu/u_cet",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = u_cet_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.u_cet, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool s_cet_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->s_cet != 0;
+}
+
+static const VMStateDescription vmstate_s_cet = {
+    .name = "cpu/s_cet",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = s_cet_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.s_cet, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool pl0_ssp_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->pl0_ssp != 0;
+}
+
+static const VMStateDescription vmstate_pl0_ssp = {
+    .name = "cpu/pl0_ssp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = pl0_ssp_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.pl0_ssp, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool pl1_ssp_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->pl1_ssp != 0;
+}
+
+static const VMStateDescription vmstate_pl1_ssp = {
+    .name = "cpu/pl1_ssp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = pl1_ssp_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.pl1_ssp, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool pl2_ssp_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->pl2_ssp != 0;
+}
+
+static const VMStateDescription vmstate_pl2_ssp = {
+    .name = "cpu/pl2_ssp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = pl2_ssp_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.pl2_ssp, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+
+static bool pl3_ssp_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->pl3_ssp != 0;
+}
+
+static const VMStateDescription vmstate_pl3_ssp = {
+    .name = "cpu/pl3_ssp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = pl3_ssp_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.pl3_ssp, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool ssp_tbl_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->ssp_tbl != 0;
+}
+
+static const VMStateDescription vmstate_ssp_tbl = {
+    .name = "cpu/ssp_tbl",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = ssp_tbl_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.ssp_tbl, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool guest_ssp_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->guest_ssp != 0;
+}
+
+static const VMStateDescription vmstate_guest_ssp = {
+    .name = "cpu/guest_ssp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = guest_ssp_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(env.guest_ssp, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 #ifdef TARGET_X86_64
 static bool pkru_needed(void *opaque)
 {
@@ -1447,6 +1600,14 @@ VMStateDescription vmstate_x86_cpu = {
         &vmstate_nested_state,
 #endif
         &vmstate_msr_tsx_ctrl,
+        &vmstate_u_cet,
+        &vmstate_s_cet,
+        &vmstate_pl0_ssp,
+        &vmstate_pl1_ssp,
+        &vmstate_pl2_ssp,
+        &vmstate_pl3_ssp,
+        &vmstate_ssp_tbl,
+        &vmstate_guest_ssp,
         NULL
     }
 };
-- 
2.17.2