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

[Liu, Jinsong]

Eduardo, Jan, Andreas

As we sync 3 months ago, I wait until qemu1.1 done, then re-write patch based 
on qemu1.1.
Now it's time to re-write my patch based on qemu1.1.

Attached is a RFC patch for exposing tsc deadline timer to guest.
I have checked current qemu1.1 code, and read some emails regarding to cpuid 
exposing these days.
However, I think I may ignore something (so many discussion :-), so if you 
think anything wrong, please point out to me.

Thanks,
Jinsong

====================
>From 8b5b003f6f8834d2d5d71e18bb47b7f089bc4928 Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <address@hidden>
Date: Tue, 3 Jul 2012 02:35:10 +0800
Subject: [PATCH] Expose tsc deadline timer feature to guest

This patch exposes tsc deadline timer feature to guest if
1). in-kernel irqchip is used, and
2). kvm has emulated tsc deadline timer, and
3). user authorize the feature exposing via -cpu or +/- tsc-deadline

Signed-off-by: Liu, Jinsong <address@hidden>
---
 target-i386/cpu.h |    1 +
 target-i386/kvm.c |    5 +++++
 2 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 79cc640..d1a4a04 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -400,6 +400,7 @@
 #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 0d0d8f6..52b577f 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -361,8 +361,13 @@ int kvm_arch_init_vcpu(CPUX86State *env)
     env->cpuid_features &= kvm_arch_get_supported_cpuid(s, 1, 0, R_EDX);
 
     i = env->cpuid_ext_features & CPUID_EXT_HYPERVISOR;
+    j = env->cpuid_ext_features & CPUID_EXT_TSC_DEADLINE_TIMER;
     env->cpuid_ext_features &= kvm_arch_get_supported_cpuid(s, 1, 0, R_ECX);
     env->cpuid_ext_features |= i;
+    if (j && 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);
-- 
1.7.1

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