>
> My point is that
>
> qemu-version-A [-cpu whatever]
>
> should provide the same VM as
>
> qemu-version-B -machine pc-A [-cpu whatever]
>
> specifically if you leave out the cpu specification.
>
> So the compat machine could establish a feature mask (e.g. append some
> "-tsc_deadline" in this case). But, indeed, we need a new channel for
> this.
>
Yes, if such requirement need to be satisfied, I agree we need a new channel to solve this kind of common issue.
As for tsc deadline timer feature exposing, I write an updated patch as attached.
1). It exposes tsc deadline timer feature to guest if in-kernel irqchip is used and kvm has emulated tsc deadline timer;
2). It also authorizes user to control the feature exposing via a cpu feature flag;
Thanks,
Jinsong
====================
>From 5b7d5f459b621686e78e437010ce34748bcb9e8e Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
Date: Wed, 29 Feb 2012 01:53:15 +0800
Subject: [PATCH] Expose tsc deadline timer feature to guest
It exposes tsc deadline timer feature to guest if in-kernel irqchip is used
and kvm has emulated tsc deadline timer.
It also authorizes user to control the feature exposing via a cpu feature flag.
Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
---
target-i386/cpu.h | 1 +
target-i386/cpuid.c | 2 +-
target-i386/kvm.c | 4 ++++
3 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index d92be5d..3409afe 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/cpuid.c b/target-i386/cpuid.c
index b9bfeaf..ac4b79c 100644
--- a/target-i386/cpuid.c
+++ b/target-i386/cpuid.c
@@ -50,7 +50,7 @@ static const char *ext_feature_name[] = {
"fma", "cx16", "xtpr", "pdcm",
NULL, NULL, "dca", "sse4.1|sse4_1",
"sse4.2|sse4_2", "x2apic", "movbe", "popcnt",
- NULL, "aes", "xsave", "osxsave",
+ "tsc_deadline", "aes", "xsave", "osxsave",
"avx", NULL, NULL, "hypervisor",
};
static const char *ext2_feature_name[] = {
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 7079e87..2639699 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -370,6 +370,10 @@ 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;
+ 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);
--
1.7.1
Attachment:
0001-Expose-tsc-deadline-timer-feature-to-guest.patch
Description: 0001-Expose-tsc-deadline-timer-feature-to-guest.patch
