[Qemu-devel] [PATCH] Expose tsc deadline timer cpuid to guest

[Liu, Jinsong]

>From 19caf1db1f93e6f6b736e1dfd5e91a0c7669adec Mon Sep 17 00:00:00 2001
From: Liu Jinsong <address@hidden>
Date: Tue, 27 Dec 2011 04:08:27 +0800
Subject: [PATCH] Expose tsc deadline timer cpuid to guest

Depend on several factors:
1. Considering live migration, user enable/disable tsc deadline timer;
2. If guest use kvm apic and kvm emulate tsc deadline timer, expose it;
3. If in the future qemu support tsc deadline timer emulation,
   and guest use qemu apic, add cpuid exposing case then.

Signed-off-by: Liu, Jinsong <address@hidden>
---
 linux-headers/linux/kvm.h |    1 +
 qemu-kvm.h                |    1 +
 qemu-options.hx           |    3 +++
 target-i386/cpu.h         |    1 +
 target-i386/kvm.c         |   12 ++++++++++++
 vl.c                      |    4 ++++
 6 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index a8761d3..1d3a4f4 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -558,6 +558,7 @@ struct kvm_ppc_pvinfo {
 #define KVM_CAP_PPC_PAPR 68
 #define KVM_CAP_SW_TLB 69
 #define KVM_CAP_ONE_REG 70
+#define KVM_CAP_TSC_DEADLINE_TIMER 72
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/qemu-kvm.h b/qemu-kvm.h
index 2bd5602..8c6c2ea 100644
--- a/qemu-kvm.h
+++ b/qemu-kvm.h
@@ -260,6 +260,7 @@ extern int kvm_irqchip;
 extern int kvm_pit;
 extern int kvm_pit_reinject;
 extern unsigned int kvm_shadow_memory;
+extern int tsc_deadline_timer;
 
 int kvm_handle_tpr_access(CPUState *env);
 void kvm_tpr_enable_vapic(CPUState *env);
diff --git a/qemu-options.hx b/qemu-options.hx
index f6df6b9..eff6644 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2619,6 +2619,9 @@ DEF("no-kvm-pit-reinjection", 0, 
QEMU_OPTION_no_kvm_pit_reinjection,
     "-no-kvm-pit-reinjection\n"
     "                disable KVM kernel mode PIT interrupt reinjection\n",
     QEMU_ARCH_I386)
+DEF("no-tsc-deadline-timer", 0, QEMU_OPTION_no_tsc_deadline_timer,
+    "-no-tsc-deadline-timer     disable tsc deadline timer\n",
+    QEMU_ARCH_I386)
 DEF("tdf", 0, QEMU_OPTION_tdf,
     "-tdf            enable guest time drift compensation\n", QEMU_ARCH_ALL)
 DEF("kvm-shadow-memory", HAS_ARG, QEMU_OPTION_kvm_shadow_memory,
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 177d8aa..767d2eb 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -399,6 +399,7 @@
 #define CPUID_EXT_X2APIC   (1 << 21)
 #define CPUID_EXT_MOVBE    (1 << 22)
 #define CPUID_EXT_POPCNT   (1 << 23)
+#define CPUID_EXT_TSC_DEADLINE_TIMER (1 << 24)
 #define CPUID_EXT_XSAVE    (1 << 26)
 #define CPUID_EXT_OSXSAVE  (1 << 27)
 #define CPUID_EXT_HYPERVISOR  (1 << 31)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index d50de90..740184d 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -370,6 +370,18 @@ int kvm_arch_init_vcpu(CPUState *env)
     i = env->cpuid_ext_features & CPUID_EXT_HYPERVISOR;
     env->cpuid_ext_features &= kvm_arch_get_supported_cpuid(s, 1, 0, R_ECX);
     env->cpuid_ext_features |= i;
+    /*
+     * 1. Considering live migration, user enable/disable tsc deadline timer;
+     * 2. If guest use kvm apic and kvm emulate tsc deadline timer, expose it;
+     * 3. If in the future qemu support tsc deadline timer emulation,
+     *    and guest use qemu apic, add cpuid exposing case then.
+     */
+    env->cpuid_ext_features &= ~CPUID_EXT_TSC_DEADLINE_TIMER;
+    if (tsc_deadline_timer) {
+        if (kvm_irqchip_in_kernel() &&
+            kvm_check_extension(s, KVM_CAP_TSC_DEADLINE_TIMER))
+            env->cpuid_ext_features |= CPUID_EXT_TSC_DEADLINE_TIMER;
+    }
 
     env->cpuid_ext2_features &= kvm_arch_get_supported_cpuid(s, 0x80000001,
                                                              0, R_EDX);
diff --git a/vl.c b/vl.c
index 89a618b..583de58 100644
--- a/vl.c
+++ b/vl.c
@@ -2160,6 +2160,7 @@ int kvm_irqchip = 1;
 int kvm_pit = 1;
 int kvm_pit_reinject = 1;
 #endif
+int tsc_deadline_timer = 1;
 
 int main(int argc, char **argv, char **envp)
 {
@@ -2875,6 +2876,9 @@ int main(int argc, char **argv, char **envp)
                 break;
             }
 #endif
+            case QEMU_OPTION_no_tsc_deadline_timer:
+                tsc_deadline_timer = 0;
+                break;
             case QEMU_OPTION_usb:
                 usb_enabled = 1;
                 break;
-- 
1.6.5.6

0001-Expose-tsc-deadline-timer-cpuid-to-guest.patch
Description: 0001-Expose-tsc-deadline-timer-cpuid-to-guest.patch