[PATCH v3 6/6] target/i386: Add get/set/migrate support for FRED MSRs

Xin Li
2023-11-09T07:50:24Z

FRED CPU states are managed in 9 new FRED MSRs, in addtion to a few
existing CPU registers and MSRs, e.g., CR4.FRED and MSR_IA32_PL0_SSP.

Save/restore/migrate FRED MSRs if FRED is exposed to the guest.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
target/i386/cpu.h | 22 +++++++++++++++++++
target/i386/kvm/kvm.c | 49 +++++++++++++++++++++++++++++++++++++++++++
target/i386/machine.c | 28 +++++++++++++++++++++++++
3 files changed, 99 insertions(+)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index cc3b4fefb8..3b13eceffe 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -529,6 +529,17 @@ typedef enum X86Seg {
#define MSR_IA32_XFD 0x000001c4
#define MSR_IA32_XFD_ERR 0x000001c5

+/* FRED MSRs */
+#define MSR_IA32_FRED_RSP0 0x000001cc /* Stack level 0 regular stack pointer */
+#define MSR_IA32_FRED_RSP1 0x000001cd /* Stack level 1 regular stack pointer */
+#define MSR_IA32_FRED_RSP2 0x000001ce /* Stack level 2 regular stack pointer */
+#define MSR_IA32_FRED_RSP3 0x000001cf /* Stack level 3 regular stack pointer */
+#define MSR_IA32_FRED_STKLVLS 0x000001d0 /* FRED exception stack levels */
+#define MSR_IA32_FRED_SSP1 0x000001d1 /* Stack level 1 shadow stack pointer in ring 0 */
+#define MSR_IA32_FRED_SSP2 0x000001d2 /* Stack level 2 shadow stack pointer in ring 0 */
+#define MSR_IA32_FRED_SSP3 0x000001d3 /* Stack level 3 shadow stack pointer in ring 0 */
+#define MSR_IA32_FRED_CONFIG 0x000001d4 /* FRED Entrypoint and interrupt stack level */
+
#define MSR_IA32_BNDCFGS 0x00000d90
#define MSR_IA32_XSS 0x00000da0
#define MSR_IA32_UMWAIT_CONTROL 0xe1
@@ -1687,6 +1698,17 @@ typedef struct CPUArchState {
target_ulong cstar;
target_ulong fmask;
target_ulong kernelgsbase;
+
+ /* FRED MSRs */
+ uint64_t fred_rsp0;
+ uint64_t fred_rsp1;
+ uint64_t fred_rsp2;
+ uint64_t fred_rsp3;
+ uint64_t fred_stklvls;
+ uint64_t fred_ssp1;
+ uint64_t fred_ssp2;
+ uint64_t fred_ssp3;
+ uint64_t fred_config;
#endif

uint64_t tsc_adjust;
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 11b8177eff..101ff63805 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -3309,6 +3309,17 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
kvm_msr_entry_add(cpu, MSR_KERNELGSBASE, env->kernelgsbase);
kvm_msr_entry_add(cpu, MSR_FMASK, env->fmask);
kvm_msr_entry_add(cpu, MSR_LSTAR, env->lstar);
+ if (env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_FRED) {
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP0, env->fred_rsp0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP1, env->fred_rsp1);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP2, env->fred_rsp2);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP3, env->fred_rsp3);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_STKLVLS, env->fred_stklvls);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP1, env->fred_ssp1);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP2, env->fred_ssp2);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP3, env->fred_ssp3);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_CONFIG, env->fred_config);
+ }
}
#endif

@@ -3773,6 +3784,17 @@ static int kvm_get_msrs(X86CPU *cpu)
kvm_msr_entry_add(cpu, MSR_KERNELGSBASE, 0);
kvm_msr_entry_add(cpu, MSR_FMASK, 0);
kvm_msr_entry_add(cpu, MSR_LSTAR, 0);
+ if (env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_FRED) {
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP0, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP1, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP2, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP3, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_STKLVLS, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP1, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP2, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP3, 0);
+ kvm_msr_entry_add(cpu, MSR_IA32_FRED_CONFIG, 0);
+ }
}
#endif
kvm_msr_entry_add(cpu, MSR_KVM_SYSTEM_TIME, 0);
@@ -3994,6 +4016,33 @@ static int kvm_get_msrs(X86CPU *cpu)
case MSR_LSTAR:
env->lstar = msrs[i].data;
break;
+ case MSR_IA32_FRED_RSP0:
+ env->fred_rsp0 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_RSP1:
+ env->fred_rsp1 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_RSP2:
+ env->fred_rsp2 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_RSP3:
+ env->fred_rsp3 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_STKLVLS:
+ env->fred_stklvls = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_SSP1:
+ env->fred_ssp1 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_SSP2:
+ env->fred_ssp2 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_SSP3:
+ env->fred_ssp3 = msrs[i].data;
+ break;
+ case MSR_IA32_FRED_CONFIG:
+ env->fred_config = msrs[i].data;
+ break;
#endif
case MSR_IA32_TSC:
env->tsc = msrs[i].data;
diff --git a/target/i386/machine.c b/target/i386/machine.c
index a1041ef828..850a19cb8e 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -1544,6 +1544,33 @@ static const VMStateDescription vmstate_msr_xfd = {
};

#ifdef TARGET_X86_64
+static bool intel_fred_msrs_needed(void *opaque)
+{
+ X86CPU *cpu = opaque;
+ CPUX86State *env = &cpu->env;
+
+ return !!(env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_FRED);
+}
+
+static const VMStateDescription vmstate_msr_fred = {
+ .name = "cpu/fred",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = intel_fred_msrs_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(env.fred_rsp0, X86CPU),
+ VMSTATE_UINT64(env.fred_rsp1, X86CPU),
+ VMSTATE_UINT64(env.fred_rsp2, X86CPU),
+ VMSTATE_UINT64(env.fred_rsp3, X86CPU),
+ VMSTATE_UINT64(env.fred_stklvls, X86CPU),
+ VMSTATE_UINT64(env.fred_ssp1, X86CPU),
+ VMSTATE_UINT64(env.fred_ssp2, X86CPU),
+ VMSTATE_UINT64(env.fred_ssp3, X86CPU),
+ VMSTATE_UINT64(env.fred_config, X86CPU),
+ VMSTATE_END_OF_LIST()
+ }
+ };
+
static bool amx_xtile_needed(void *opaque)
{
X86CPU *cpu = opaque;
@@ -1747,6 +1774,7 @@ const VMStateDescription vmstate_x86_cpu = {
&vmstate_pdptrs,
&vmstate_msr_xfd,
#ifdef TARGET_X86_64
+ &vmstate_msr_fred,
&vmstate_amx_xtile,
#endif
&vmstate_arch_lbr,
--
2.42.0