Re: [RFC PATCH] Expose tsc deadline timer feature to guest

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-07-02 13:08, Liu, Jinsong wrote:
> 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 <jinsong.liu@intel.com>
> 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 <jinsong.liu@intel.com>
> ---
>  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);
> 

Fine with me.

Acked-by: Jan Kiszka <jan.kiszka@siemens.com>

Jan

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