From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH] revert part of 3db8b916e merge
Date: Wed, 3 Jun 2009 15:20:40 +0300
Message-ID: <20090603122040.GD11384@redhat.com>
References: <20090603120756.GC11384@redhat.com> <4A2669AE.3010602@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: kvm@vger.kernel.org
To: Avi Kivity <avi@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx2.redhat.com ([66.187.237.31]:57973 "EHLO mx2.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753061AbZFCMUk (ORCPT <rfc822;kvm@vger.kernel.org>);
	Wed, 3 Jun 2009 08:20:40 -0400
Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26])
	by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n53CKgGR006405
	for <kvm@vger.kernel.org>; Wed, 3 Jun 2009 08:20:42 -0400
Content-Disposition: inline
In-Reply-To: <4A2669AE.3010602@redhat.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On Wed, Jun 03, 2009 at 03:16:46PM +0300, Avi Kivity wrote:
> Gleb Natapov wrote:
>> kvm_*_mpstate() cannot be called from kvm_arch_*_registers()
>> since kvm_arch_*_registers() sometimes called from io thread, but
>> kvm_*_mpstate() can be called only by cpu thread.
>>
>>   
>
> I really dislike vcpu functions to be called from outside the vcpu  
> thread.  Who are the callers?
>
monitor.c. May be others (git grep cpu_synchronize_state). But
kvm_save_registers() does the right thing and calls another function on
vcpu thread.

>> Signed-off-by: Gleb Natapov <gleb@redhat.com>
>> diff --git a/qemu-kvm.c b/qemu-kvm.c
>> index 68d3b92..7ed1e06 100644
>> --- a/qemu-kvm.c
>> +++ b/qemu-kvm.c
>> @@ -1431,26 +1431,3 @@ void qemu_kvm_cpu_stop(CPUState *env)
>>      if (kvm_enabled())
>>          env->kvm_cpu_state.stopped = 1;
>>  }
>> -
>> -void kvm_arch_get_registers(CPUState *env)
>> -{
>> -    kvm_save_registers(env);
>> -    kvm_save_mpstate(env);
>> -}
>> -
>> -void kvm_arch_put_registers(CPUState *env)
>> -{
>> -    kvm_load_registers(env);
>> -    kvm_load_mpstate(env);
>> -}
>> -
>> -
>> -void cpu_synchronize_state(CPUState *env, int modified)
>> -{
>> -    if (kvm_enabled()) {
>> -        if (modified)
>> -            kvm_arch_put_registers(env);
>> -        else
>> -            kvm_arch_get_registers(env);
>> -    }
>> -}
>> diff --git a/qemu-kvm.h b/qemu-kvm.h
>> index 725589b..5d47e88 100644
>> --- a/qemu-kvm.h
>> +++ b/qemu-kvm.h
>> @@ -216,10 +216,25 @@ int kvm_log_stop(target_phys_addr_t phys_addr, target_phys_addr_t len);
>>   static inline int kvm_sync_vcpus(void) { return 0; }
>>  -void kvm_arch_get_registers(CPUState *env);
>> -void kvm_arch_put_registers(CPUState *env);
>> +static inline void kvm_arch_get_registers(CPUState *env)
>> +{
>> +    kvm_save_registers(env);
>> +}
>>  -void cpu_synchronize_state(CPUState *env, int modified);
>> +static inline void kvm_arch_put_registers(CPUState *env)
>> +{
>> +    kvm_load_registers(env);
>> +}
>> +
>> +static inline void cpu_synchronize_state(CPUState *env, int modified)
>> +{
>> +    if (kvm_enabled()) {
>> +        if (modified)
>> +            kvm_arch_put_registers(env);
>> +        else
>> +            kvm_arch_get_registers(env);
>> +    }
>> +}
>>   uint32_t kvm_arch_get_supported_cpuid(CPUState *env, uint32_t 
>> function,
>>                                        int reg);
>> diff --git a/target-i386/machine.c b/target-i386/machine.c
>> index f280d3d..07df1e1 100644
>> --- a/target-i386/machine.c
>> +++ b/target-i386/machine.c
>> @@ -32,7 +32,10 @@ void cpu_save(QEMUFile *f, void *opaque)
>>      int32_t pending_irq;
>>      int i, bit;
>>  -    cpu_synchronize_state(env, 0);
>> +    if (kvm_enabled()) {
>> +        kvm_save_registers(env);
>> +        kvm_save_mpstate(env);
>> +    }
>>       for(i = 0; i < CPU_NB_REGS; i++)
>>          qemu_put_betls(f, &env->regs[i]);
>> --
>> 			Gleb.
>>   
>
>
> -- 
> Do not meddle in the internals of kernels, for they are subtle and quick to panic.

--
			Gleb.