[PATCH v12 1/7] i386/tcg: implement x2APIC registers MSR access

[Bui Quang Minh <minhquangbui99@gmail.com>]

This commit creates apic_register_read/write which are used by both
apic_mem_read/write for MMIO access and apic_msr_read/write for MSR access.

The apic_msr_read/write returns -1 on error, accelerator can use this to
raise the appropriate exception.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
---
 hw/intc/apic.c                       | 122 ++++++++++++++++++++-------
 hw/intc/trace-events                 |   4 +-
 include/hw/i386/apic.h               |   3 +
 target/i386/cpu.h                    |   3 +
 target/i386/tcg/sysemu/misc_helper.c |  27 ++++++
 5 files changed, 127 insertions(+), 32 deletions(-)

diff --git a/hw/intc/apic.c b/hw/intc/apic.c
index ac3d47d231..7a349c0723 100644
--- a/hw/intc/apic.c
+++ b/hw/intc/apic.c
@@ -288,6 +288,13 @@ void apic_deliver_irq(uint8_t dest, uint8_t dest_mode, uint8_t delivery_mode,
     apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, trigger_mode);
 }
 
+bool is_x2apic_mode(DeviceState *dev)
+{
+    APICCommonState *s = APIC(dev);
+
+    return s->apicbase & MSR_IA32_APICBASE_EXTD;
+}
+
 static void apic_set_base(APICCommonState *s, uint64_t val)
 {
     s->apicbase = (val & 0xfffff000) |
@@ -636,24 +643,19 @@ static void apic_timer(void *opaque)
     apic_timer_update(s, s->next_time);
 }
 
-static uint64_t apic_mem_read(void *opaque, hwaddr addr, unsigned size)
+static int apic_register_read(int index, uint64_t *value)
 {
     DeviceState *dev;
     APICCommonState *s;
     uint32_t val;
-    int index;
-
-    if (size < 4) {
-        return 0;
-    }
+    int ret = 0;
 
     dev = cpu_get_current_apic();
     if (!dev) {
-        return 0;
+        return -1;
     }
     s = APIC(dev);
 
-    index = (addr >> 4) & 0xff;
     switch(index) {
     case 0x02: /* id */
         val = s->id << 24;
@@ -718,12 +720,46 @@ static uint64_t apic_mem_read(void *opaque, hwaddr addr, unsigned size)
     default:
         s->esr |= APIC_ESR_ILLEGAL_ADDRESS;
         val = 0;
+        ret = -1;
         break;
     }
-    trace_apic_mem_readl(addr, val);
+
+    trace_apic_register_read(index, val);
+    *value = val;
+    return ret;
+}
+
+static uint64_t apic_mem_read(void *opaque, hwaddr addr, unsigned size)
+{
+    uint64_t val;
+    int index;
+
+    if (size < 4) {
+        return 0;
+    }
+
+    index = (addr >> 4) & 0xff;
+    apic_register_read(index, &val);
+
     return val;
 }
 
+int apic_msr_read(int index, uint64_t *val)
+{
+    DeviceState *dev;
+
+    dev = cpu_get_current_apic();
+    if (!dev) {
+        return -1;
+    }
+
+    if (!is_x2apic_mode(dev)) {
+        return -1;
+    }
+
+    return apic_register_read(index, val);
+}
+
 static void apic_send_msi(MSIMessage *msi)
 {
     uint64_t addr = msi->address;
@@ -737,35 +773,18 @@ static void apic_send_msi(MSIMessage *msi)
     apic_deliver_irq(dest, dest_mode, delivery, vector, trigger_mode);
 }
 
-static void apic_mem_write(void *opaque, hwaddr addr, uint64_t val,
-                           unsigned size)
+static int apic_register_write(int index, uint64_t val)
 {
     DeviceState *dev;
     APICCommonState *s;
-    int index = (addr >> 4) & 0xff;
-
-    if (size < 4) {
-        return;
-    }
-
-    if (addr > 0xfff || !index) {
-        /* MSI and MMIO APIC are at the same memory location,
-         * but actually not on the global bus: MSI is on PCI bus
-         * APIC is connected directly to the CPU.
-         * Mapping them on the global bus happens to work because
-         * MSI registers are reserved in APIC MMIO and vice versa. */
-        MSIMessage msi = { .address = addr, .data = val };
-        apic_send_msi(&msi);
-        return;
-    }
 
     dev = cpu_get_current_apic();
     if (!dev) {
-        return;
+        return -1;
     }
     s = APIC(dev);
 
-    trace_apic_mem_writel(addr, val);
+    trace_apic_register_write(index, val);
 
     switch(index) {
     case 0x02:
@@ -839,8 +858,51 @@ static void apic_mem_write(void *opaque, hwaddr addr, uint64_t val,
         break;
     default:
         s->esr |= APIC_ESR_ILLEGAL_ADDRESS;
-        break;
+        return -1;
     }
+
+    return 0;
+}
+
+static void apic_mem_write(void *opaque, hwaddr addr, uint64_t val,
+                           unsigned size)
+{
+    int index = (addr >> 4) & 0xff;
+
+    if (size < 4) {
+        return;
+    }
+
+    if (addr > 0xfff || !index) {
+        /*
+         * MSI and MMIO APIC are at the same memory location,
+         * but actually not on the global bus: MSI is on PCI bus
+         * APIC is connected directly to the CPU.
+         * Mapping them on the global bus happens to work because
+         * MSI registers are reserved in APIC MMIO and vice versa.
+         */
+        MSIMessage msi = { .address = addr, .data = val };
+        apic_send_msi(&msi);
+        return;
+    }
+
+    apic_register_write(index, val);
+}
+
+int apic_msr_write(int index, uint64_t val)
+{
+    DeviceState *dev;
+
+    dev = cpu_get_current_apic();
+    if (!dev) {
+        return -1;
+    }
+
+    if (!is_x2apic_mode(dev)) {
+        return -1;
+    }
+
+    return apic_register_write(index, val);
 }
 
 static void apic_pre_save(APICCommonState *s)
diff --git a/hw/intc/trace-events b/hw/intc/trace-events
index 36ff71f947..1ef29d0256 100644
--- a/hw/intc/trace-events
+++ b/hw/intc/trace-events
@@ -14,8 +14,8 @@ cpu_get_apic_base(uint64_t val) "0x%016"PRIx64
 # apic.c
 apic_local_deliver(int vector, uint32_t lvt) "vector %d delivery mode %d"
 apic_deliver_irq(uint8_t dest, uint8_t dest_mode, uint8_t delivery_mode, uint8_t vector_num, uint8_t trigger_mode) "dest %d dest_mode %d delivery_mode %d vector %d trigger_mode %d"
-apic_mem_readl(uint64_t addr, uint32_t val)  "0x%"PRIx64" = 0x%08x"
-apic_mem_writel(uint64_t addr, uint32_t val) "0x%"PRIx64" = 0x%08x"
+apic_register_read(uint8_t reg, uint64_t val) "register 0x%02x = 0x%"PRIx64
+apic_register_write(uint8_t reg, uint64_t val) "register 0x%02x = 0x%"PRIx64
 
 # ioapic.c
 ioapic_set_remote_irr(int n) "set remote irr for pin %d"
diff --git a/include/hw/i386/apic.h b/include/hw/i386/apic.h
index bdc15a7a73..ddea4213db 100644
--- a/include/hw/i386/apic.h
+++ b/include/hw/i386/apic.h
@@ -18,6 +18,9 @@ void apic_sipi(DeviceState *s);
 void apic_poll_irq(DeviceState *d);
 void apic_designate_bsp(DeviceState *d, bool bsp);
 int apic_get_highest_priority_irr(DeviceState *dev);
+int apic_msr_read(int index, uint64_t *val);
+int apic_msr_write(int index, uint64_t val);
+bool is_x2apic_mode(DeviceState *d);
 
 /* pc.c */
 DeviceState *cpu_get_current_apic(void);
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 7f0786e8b9..5138dd9ff2 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -545,6 +545,9 @@ typedef enum X86Seg {
 #define MSR_IA32_VMX_TRUE_ENTRY_CTLS     0x00000490
 #define MSR_IA32_VMX_VMFUNC             0x00000491
 
+#define MSR_APIC_START                  0x00000800
+#define MSR_APIC_END                    0x000008ff
+
 #define XSTATE_FP_BIT                   0
 #define XSTATE_SSE_BIT                  1
 #define XSTATE_YMM_BIT                  2
diff --git a/target/i386/tcg/sysemu/misc_helper.c b/target/i386/tcg/sysemu/misc_helper.c
index 1ddfc9fe09..1c43a9f4f7 100644
--- a/target/i386/tcg/sysemu/misc_helper.c
+++ b/target/i386/tcg/sysemu/misc_helper.c
@@ -25,6 +25,7 @@
 #include "exec/address-spaces.h"
 #include "exec/exec-all.h"
 #include "tcg/helper-tcg.h"
+#include "hw/i386/apic.h"
 
 void helper_outb(CPUX86State *env, uint32_t port, uint32_t data)
 {
@@ -289,6 +290,19 @@ void helper_wrmsr(CPUX86State *env)
         env->msr_bndcfgs = val;
         cpu_sync_bndcs_hflags(env);
         break;
+    case MSR_APIC_START ... MSR_APIC_END: {
+        int ret;
+        int index = (uint32_t)env->regs[R_ECX] - MSR_APIC_START;
+
+        bql_lock();
+        ret = apic_msr_write(index, val);
+        bql_unlock();
+        if (ret < 0) {
+            goto error;
+        }
+
+        break;
+    }
     default:
         if ((uint32_t)env->regs[R_ECX] >= MSR_MC0_CTL
             && (uint32_t)env->regs[R_ECX] < MSR_MC0_CTL +
@@ -455,6 +469,19 @@ void helper_rdmsr(CPUX86State *env)
         val = (cs->nr_threads * cs->nr_cores) | (cs->nr_cores << 16);
         break;
     }
+    case MSR_APIC_START ... MSR_APIC_END: {
+        int ret;
+        int index = (uint32_t)env->regs[R_ECX] - MSR_APIC_START;
+
+        bql_lock();
+        ret = apic_msr_read(index, &val);
+        bql_unlock();
+        if (ret < 0) {
+            raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC());
+        }
+
+        break;
+    }
     default:
         if ((uint32_t)env->regs[R_ECX] >= MSR_MC0_CTL
             && (uint32_t)env->regs[R_ECX] < MSR_MC0_CTL +
-- 
2.25.1