apic, i386/tcg: add x2apic transitions

This commit adds support for x2APIC transitions when writing to
MSR_IA32_APICBASE register and finally adds CPUID_EXT_X2APIC to
TCG_EXT_FEATURES.

The set_base in APICCommonClass now returns an integer to indicate error in
execution. apic_set_base return -1 on invalid APIC state transition,
accelerator can use this to raise appropriate exception.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Message-Id: <20240111154404.5333-4-minhquangbui99@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/kvm/apic.c

@@ -95,9 +95,10 @@ void kvm_get_apic_state(DeviceState *dev, struct kvm_lapic_state *kapic)
     apic_next_timer(s, s->initial_count_load_time);
 }
 
-static void kvm_apic_set_base(APICCommonState *s, uint64_t val)
+static int kvm_apic_set_base(APICCommonState *s, uint64_t val)
 {
     s->apicbase = val;
+    return 0;
 }
 
 static void kvm_apic_set_tpr(APICCommonState *s, uint8_t val)

hw/i386/xen/xen_apic.c

@@ -49,8 +49,9 @@ static void xen_apic_realize(DeviceState *dev, Error **errp)
     msi_nonbroken = true;
 }
 
-static void xen_apic_set_base(APICCommonState *s, uint64_t val)
+static int xen_apic_set_base(APICCommonState *s, uint64_t val)
 {
+    return 0;
 }
 
 static void xen_apic_set_tpr(APICCommonState *s, uint8_t val)

hw/intc/apic.c

@@ -308,8 +308,49 @@ bool is_x2apic_mode(DeviceState *dev)
     return s->apicbase & MSR_IA32_APICBASE_EXTD;
 }
 
-static void apic_set_base(APICCommonState *s, uint64_t val)
+static int apic_set_base_check(APICCommonState *s, uint64_t val)
 {
+    /* Enable x2apic when x2apic is not supported by CPU */
+    if (!cpu_has_x2apic_feature(&s->cpu->env) &&
+        val & MSR_IA32_APICBASE_EXTD) {
+        return -1;
+    }
+
+    /*
+     * Transition into invalid state
+     * (s->apicbase & MSR_IA32_APICBASE_ENABLE == 0) &&
+     * (s->apicbase & MSR_IA32_APICBASE_EXTD) == 1
+     */
+    if (!(val & MSR_IA32_APICBASE_ENABLE) &&
+        (val & MSR_IA32_APICBASE_EXTD)) {
+        return -1;
+    }
+
+    /* Invalid transition from disabled mode to x2APIC */
+    if (!(s->apicbase & MSR_IA32_APICBASE_ENABLE) &&
+        !(s->apicbase & MSR_IA32_APICBASE_EXTD) &&
+        (val & MSR_IA32_APICBASE_ENABLE) &&
+        (val & MSR_IA32_APICBASE_EXTD)) {
+        return -1;
+    }
+
+    /* Invalid transition from x2APIC to xAPIC */
+    if ((s->apicbase & MSR_IA32_APICBASE_ENABLE) &&
+        (s->apicbase & MSR_IA32_APICBASE_EXTD) &&
+        (val & MSR_IA32_APICBASE_ENABLE) &&
+        !(val & MSR_IA32_APICBASE_EXTD)) {
+        return -1;
+    }
+
+    return 0;
+}
+
+static int apic_set_base(APICCommonState *s, uint64_t val)
+{
+    if (apic_set_base_check(s, val) < 0) {
+        return -1;
+    }
+
     s->apicbase = (val & 0xfffff000) |
         (s->apicbase & (MSR_IA32_APICBASE_BSP | MSR_IA32_APICBASE_ENABLE));
     /* if disabled, cannot be enabled again */
@@ -318,6 +359,25 @@ static void apic_set_base(APICCommonState *s, uint64_t val)
         cpu_clear_apic_feature(&s->cpu->env);
         s->spurious_vec &= ~APIC_SV_ENABLE;
     }
+
+    /* Transition from disabled mode to xAPIC */
+    if (!(s->apicbase & MSR_IA32_APICBASE_ENABLE) &&
+        (val & MSR_IA32_APICBASE_ENABLE)) {
+        s->apicbase |= MSR_IA32_APICBASE_ENABLE;
+        cpu_set_apic_feature(&s->cpu->env);
+    }
+
+    /* Transition from xAPIC to x2APIC */
+    if (cpu_has_x2apic_feature(&s->cpu->env) &&
+        !(s->apicbase & MSR_IA32_APICBASE_EXTD) &&
+        (val & MSR_IA32_APICBASE_EXTD)) {
+        s->apicbase |= MSR_IA32_APICBASE_EXTD;
+
+        s->log_dest = ((s->initial_apic_id & 0xffff0) << 16) |
+                      (1 << (s->initial_apic_id & 0xf));
+    }
+
+    return 0;
 }
 
 static void apic_set_tpr(APICCommonState *s, uint8_t val)

hw/intc/apic_common.c

@@ -35,20 +35,19 @@
 
 bool apic_report_tpr_access;
 
-void cpu_set_apic_base(DeviceState *dev, uint64_t val)
+int cpu_set_apic_base(DeviceState *dev, uint64_t val)
 {
     trace_cpu_set_apic_base(val);
 
     if (dev) {
         APICCommonState *s = APIC_COMMON(dev);
         APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
-        /* switching to x2APIC, reset possibly modified xAPIC ID */
-        if (!(s->apicbase & MSR_IA32_APICBASE_EXTD) &&
-            (val & MSR_IA32_APICBASE_EXTD)) {
-            s->id = s->initial_apic_id;
-        }
-        info->set_base(s, val);
+        /* Reset possibly modified xAPIC ID */
+        s->id = s->initial_apic_id;
+        return info->set_base(s, val);
     }
+
+    return 0;
 }
 
 uint64_t cpu_get_apic_base(DeviceState *dev)

include/hw/i386/apic.h

@@ -8,7 +8,7 @@ int apic_accept_pic_intr(DeviceState *s);
 void apic_deliver_pic_intr(DeviceState *s, int level);
 void apic_deliver_nmi(DeviceState *d);
 int apic_get_interrupt(DeviceState *s);
-void cpu_set_apic_base(DeviceState *s, uint64_t val);
+int cpu_set_apic_base(DeviceState *s, uint64_t val);
 uint64_t cpu_get_apic_base(DeviceState *s);
 void cpu_set_apic_tpr(DeviceState *s, uint8_t val);
 uint8_t cpu_get_apic_tpr(DeviceState *s);

include/hw/i386/apic_internal.h

@@ -137,7 +137,7 @@ struct APICCommonClass {
 
     DeviceRealize realize;
     DeviceUnrealize unrealize;
-    void (*set_base)(APICCommonState *s, uint64_t val);
+    int (*set_base)(APICCommonState *s, uint64_t val);
     void (*set_tpr)(APICCommonState *s, uint8_t val);
     uint8_t (*get_tpr)(APICCommonState *s);
     void (*enable_tpr_reporting)(APICCommonState *s, bool enable);

target/i386/cpu.c

@@ -631,8 +631,8 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
  * in CPL=3; remove them if they are ever implemented for system emulation.
  */
 #if defined CONFIG_USER_ONLY
-#define CPUID_EXT_KERNEL_FEATURES (CPUID_EXT_PCID | CPUID_EXT_TSC_DEADLINE_TIMER | \
-                                 CPUID_EXT_X2APIC)
+#define CPUID_EXT_KERNEL_FEATURES \
+          (CPUID_EXT_PCID | CPUID_EXT_TSC_DEADLINE_TIMER)
 #else
 #define CPUID_EXT_KERNEL_FEATURES 0
 #endif
@@ -642,12 +642,13 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
           CPUID_EXT_XSAVE | /* CPUID_EXT_OSXSAVE is dynamic */   \
           CPUID_EXT_MOVBE | CPUID_EXT_AES | CPUID_EXT_HYPERVISOR | \
           CPUID_EXT_RDRAND | CPUID_EXT_AVX | CPUID_EXT_F16C | \
-          CPUID_EXT_FMA | CPUID_EXT_KERNEL_FEATURES)
+          CPUID_EXT_FMA | CPUID_EXT_X2APIC | CPUID_EXT_KERNEL_FEATURES)
           /* missing:
           CPUID_EXT_DTES64, CPUID_EXT_DSCPL, CPUID_EXT_VMX, CPUID_EXT_SMX,
           CPUID_EXT_EST, CPUID_EXT_TM2, CPUID_EXT_CID,
           CPUID_EXT_XTPR, CPUID_EXT_PDCM, CPUID_EXT_PCID, CPUID_EXT_DCA,
-          CPUID_EXT_X2APIC, CPUID_EXT_TSC_DEADLINE_TIMER */
+          CPUID_EXT_TSC_DEADLINE_TIMER
+          */
 
 #ifdef TARGET_X86_64
 #define TCG_EXT2_X86_64_FEATURES CPUID_EXT2_LM

target/i386/cpu.h

@@ -379,6 +379,10 @@ typedef enum X86Seg {
 #define MSR_IA32_APICBASE_ENABLE        (1<<11)
 #define MSR_IA32_APICBASE_EXTD          (1 << 10)
 #define MSR_IA32_APICBASE_BASE          (0xfffffU<<12)
+#define MSR_IA32_APICBASE_RESERVED \
+        (~(uint64_t)(MSR_IA32_APICBASE_BSP | MSR_IA32_APICBASE_ENABLE \
+                     | MSR_IA32_APICBASE_EXTD | MSR_IA32_APICBASE_BASE))
+
 #define MSR_IA32_FEATURE_CONTROL        0x0000003a
 #define MSR_TSC_ADJUST                  0x0000003b
 #define MSR_IA32_SPEC_CTRL              0x48

target/i386/tcg/sysemu/misc_helper.c

@@ -158,9 +158,19 @@ void helper_wrmsr(CPUX86State *env)
     case MSR_IA32_SYSENTER_EIP:
         env->sysenter_eip = val;
         break;
-    case MSR_IA32_APICBASE:
-        cpu_set_apic_base(env_archcpu(env)->apic_state, val);
+    case MSR_IA32_APICBASE: {
+        int ret;
+
+        if (val & MSR_IA32_APICBASE_RESERVED) {
+            goto error;
+        }
+
+        ret = cpu_set_apic_base(env_archcpu(env)->apic_state, val);
+        if (ret < 0) {
+            goto error;
+        }
         break;
+    }
     case MSR_EFER:
         {
             uint64_t update_mask;

target/i386/whpx/whpx-apic.c

@@ -90,9 +90,10 @@ static void whpx_get_apic_state(APICCommonState *s,
     apic_next_timer(s, s->initial_count_load_time);
 }
 
-static void whpx_apic_set_base(APICCommonState *s, uint64_t val)
+static int whpx_apic_set_base(APICCommonState *s, uint64_t val)
 {
     s->apicbase = val;
+    return 0;
 }
 
 static void whpx_put_apic_base(CPUState *cpu, uint64_t val)