[patch 6/7] kvm: qemu: enable in-kernel C2 emulation / userspace emulation

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: inkernel-acpic2-enable --]
[-- Type: text/plain, Size: 3414 bytes --]

Enable the in-kernel C2 emulation after the _CST notification has been
triggered.

Emulate in userspace for -no-kvm-irqchip case.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm-userspace.tip/qemu/hw/acpi.c
===================================================================
--- kvm-userspace.tip.orig/qemu/hw/acpi.c
+++ kvm-userspace.tip/qemu/hw/acpi.c
@@ -124,6 +124,7 @@ static void pm_tmr_timer(void *opaque)
  * Fake C2 emulation, so the OS will consider the TSC unreliable
  * and fallback to C1 after the latency is updated to a high value
  * in acpi-dsdt.dsl.
+ * We still emulate C2 halt in case the OS ignores the _CST notification.
  */
 static void qemu_system_cpu_power_notify(void);
 static uint32_t pm_ioport_readb(void *opaque, uint32_t addr)
@@ -131,7 +132,12 @@ static uint32_t pm_ioport_readb(void *op
     addr &= 0x3f;
     switch (addr) {
     case 0x14: /* P_LVL2 */
-         qemu_system_cpu_power_notify();
+        if (!cst_notified)
+            qemu_system_cpu_power_notify();
+            cst_notified = 1;
+         } else {
+            qemu_kvm_handle_plvl2_read();
+         }
     }
 #ifdef DEBUG
     printf("pm_ioport_readb addr=%x\n", addr);
@@ -791,10 +797,12 @@ void qemu_system_cpu_hot_add(int cpu, in
 
 static void qemu_system_cpu_power_notify(void)
 {
-    power_gpe.disable = 1;
+    if (kvm_irqchip_in_kernel(kvm_context)) {
+        power_gpe.disable = 1;
 
-    qemu_set_irq(pm_state->irq, 1);
-    qemu_set_irq(pm_state->irq, 0);
+        qemu_set_irq(pm_state->irq, 1);
+        qemu_set_irq(pm_state->irq, 0);
+    }
 }
 
 #endif
Index: kvm-userspace.tip/qemu/qemu-kvm-x86.c
===================================================================
--- kvm-userspace.tip.orig/qemu/qemu-kvm-x86.c
+++ kvm-userspace.tip/qemu/qemu-kvm-x86.c
@@ -287,6 +287,21 @@ void kvm_load_mpstate(CPUState *env)
 #endif
 }
 
+uint32_t qemu_kvm_handle_plvl2_read(void)
+{
+    CPUState *env = cpu_single_env;
+    uint32_t ret;
+
+    if (kvm_irqchip_in_kernel(kvm_context)) {
+        kvm_enable_acpi_c2(kvm_context);
+        ret = 0;
+    } else {
+        kvm_arch_halt(NULL, env->cpu_index);
+        ret = 1;
+    }
+    return ret;
+}
+
 void kvm_arch_save_regs(CPUState *env)
 {
     struct kvm_regs regs;
Index: kvm-userspace.tip/qemu/qemu-kvm.h
===================================================================
--- kvm-userspace.tip.orig/qemu/qemu-kvm.h
+++ kvm-userspace.tip/qemu/qemu-kvm.h
@@ -88,6 +88,9 @@ void qemu_kvm_system_reset_request(void)
 int handle_powerpc_dcr_read(int vcpu, uint32_t dcrn, uint32_t *data);
 int handle_powerpc_dcr_write(int vcpu,uint32_t dcrn, uint32_t data);
 #endif
+#if defined(TARGET_I386) || defined(TARGET_X86_64) || defined (TARGET_IA64)
+uint32_t qemu_kvm_handle_plvl2_read(void);
+#endif
 
 #if !defined(SYS_signalfd)
 struct signalfd_siginfo {
Index: kvm-userspace.tip/qemu/qemu-kvm.c
===================================================================
--- kvm-userspace.tip.orig/qemu/qemu-kvm.c
+++ kvm-userspace.tip/qemu/qemu-kvm.c
@@ -619,6 +619,12 @@ static int kvm_debug(void *opaque, int v
 static int kvm_inb(void *opaque, uint16_t addr, uint8_t *data)
 {
     *data = cpu_inb(0, addr);
+    /*
+     * reads from the ACPI LVL2 port are similar to HLT emulation,
+     * so make current thread go sleep in main_loop().
+     */
+    if (addr == 0xb014 && *data)
+        return 1;
     return 0;
 }
 

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