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Re: [Qemu-devel] [RFC qom-cpu v2 1/8] apic: remove apic_no from apic_ini
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [RFC qom-cpu v2 1/8] apic: remove apic_no from apic_init_common() |
Date: |
Tue, 10 Sep 2013 14:16:25 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 |
Am 10.09.2013 14:09, schrieb Igor Mammedov:
> On Tue, 10 Sep 2013 17:43:41 +0800
> Chen Fan <address@hidden> wrote:
>
>> the 'apic_no' is increased by one when initialize/create a vCPU each time,
>> which causes APICCommonState s->idx always is increased.
>> but if we want to re-add a vCPU after removing a vCPU, we need to re-use the
>> vacant s->idx which the corresponding vCPU had been removed.
>> so we could use the unique cpu apic_id instead of the progressive s->idx.
>>
>> Signed-off-by: Chen Fan <address@hidden>
>> ---
>> hw/intc/apic_common.c | 4 +---
>> target-i386/cpu.c | 1 +
>> 2 files changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
>> index a0beb10..5568621 100644
>> --- a/hw/intc/apic_common.c
>> +++ b/hw/intc/apic_common.c
>> @@ -289,13 +289,11 @@ static int apic_init_common(ICCDevice *dev)
>> APICCommonState *s = APIC_COMMON(dev);
>> APICCommonClass *info;
>> static DeviceState *vapic;
>> - static int apic_no;
>> static bool mmio_registered;
>>
>> - if (apic_no >= MAX_APICS) {
>> + if (s->idx >= MAX_APICS) {
>> return -1;
>> }
>> - s->idx = apic_no++;
>>
>> info = APIC_COMMON_GET_CLASS(s);
>> info->init(s);
>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>> index 42c5de0..2b99683 100644
>> --- a/target-i386/cpu.c
>> +++ b/target-i386/cpu.c
>> @@ -2322,6 +2322,7 @@ static void x86_cpu_apic_create(X86CPU *cpu, Error
>> **errp)
>> /* TODO: convert to link<> */
>> apic = APIC_COMMON(env->apic_state);
>> apic->cpu = cpu;
>> + apic->idx = env->cpuid_apic_id;
> earlier here we set:
> qdev_prop_set_uint8(env->apic_state, "id", env->cpuid_apic_id);
> so apic->idx = env->cpuid_apic_id is redundant.
>
> it would be better to search by apic->id and preferably replace O(MAX_APIC)
> scans with
> a faster approach since for TCG iqr delivery might be a hot path, dropping
> MAX_APIC
> altogether and using dynamic present APICs list.
Independent of that, the recent removal of X86_CPU() cast from
x86_env_get_cpu() should allow us to finally tackle the TODO above,
moving apic_state field from CPUX86State to X86CPU.
Andreas
>
>> }
>>
>> static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp)
>
--
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- [Qemu-devel] [RFC qom-cpu v2 0/8] i386: add cpu hot remove support, Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 4/8] qom cpu: rename variable 'cpu_added_notifier' to 'cpu_hotplug_notifier', Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 2/8] x86: add x86_cpu_unrealizefn() for cpu apic remove, Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 3/8] qmp: add 'cpu-del' command support, Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 5/8] qom cpu: add UNPLUG cpu notifier support, Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 6/8] i386: implement pc interface pc_hot_del_cpu(), Chen Fan, 2013/09/10
- [Qemu-devel] [RFC qom-cpu v2 7/8] piix4: implement function cpu_status_write() for vcpu ejection, Chen Fan, 2013/09/10