From mboxrd@z Thu Jan  1 00:00:00 1970
From: Izik Eidus <ieidus@redhat.com>
Subject: Re: [PATCH] unalias rework
Date: Thu, 02 Oct 2008 18:31:58 +0300
Message-ID: <48E4E96E.6070908@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
To: kvm@vger.kernel.org
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx2.redhat.com ([66.187.237.31]:44147 "EHLO mx2.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753890AbYJBPcB (ORCPT <rfc822;kvm@vger.kernel.org>);
	Thu, 2 Oct 2008 11:32:01 -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 m92FW10X023789
	for <kvm@vger.kernel.org>; Thu, 2 Oct 2008 11:32:01 -0400
Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199])
	by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m92FW0NL021441
	for <kvm@vger.kernel.org>; Thu, 2 Oct 2008 11:32:00 -0400
Received: from [10.32.4.163] (vpn-4-163.str.redhat.com [10.32.4.163])
	by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id m92FVwKP009085
	for <kvm@vger.kernel.org>; Thu, 2 Oct 2008 11:31:59 -0400
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

Marcelo Tosatti wrote:
> Hi Izik,
>
> On Thu, Sep 04, 2008 at 05:13:20PM +0300, izik eidus wrote:
>  
>> +        struct kvm_memory_slot *alias_slot = &kvm->memslots[i];
>> +
>> +        if (alias_slot->base_gfn == slot->base_gfn)
>> +            return 1;
>> +    }
>> +    return 0;
>> +}
>> +
>> +static void update_alias_slots(struct kvm *kvm, struct 
>> kvm_memory_slot *free)
>> +{
>> +    int i;
>> +
>> +    if (is_aliased_slot(kvm, free))
>> +        return;
>> +
>> +    for (i = KVM_MEMORY_SLOTS; i < KVM_MEMORY_SLOTS + KVM_ALIAS_SLOTS;
>> +         ++i) {
>> +        struct kvm_memory_slot *alias_memslot = &kvm->memslots[i];
>> +        unsigned long size = free->npages << PAGE_SHIFT;
>> +
>> +        if (alias_memslot->userspace_addr >= free->userspace_addr &&
>> +            alias_memslot->userspace_addr < free->userspace_addr +
>> +            size) {
>> +            alias_memslot->flags = free->flags;
>> +            if (free->dirty_bitmap) {
>> +                unsigned long offset =
>> +                        alias_memslot->userspace_addr -
>> +                        free->userspace_addr;
>> +                unsigned dirty_offset;
>> +                unsigned long bitmap_addr;
>> +
>> +                offset = offset >> PAGE_SHIFT;
>> +                dirty_offset = ALIGN(offset, BITS_PER_LONG) / 8;
>> +                bitmap_addr = (unsigned long) free->dirty_bitmap;
>> +                bitmap_addr += dirty_offset;
>> +                alias_memslot->dirty_bitmap = (unsigned long *) 
>> bitmap_addr;
>> +            } else
>> +                alias_memslot->dirty_bitmap = NULL;
>> +        }
>> +    }
>> +}
>> +
>>  /*
>>   * Free any memory in @free but not in @dont.
>>   */
>> -static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
>> +static void kvm_free_physmem_slot(struct kvm *kvm,
>> +                  struct kvm_memory_slot *free,
>>                    struct kvm_memory_slot *dont)
>>  {
>>      if (!dont || free->rmap != dont->rmap)
>> @@ -385,10 +433,16 @@ static void kvm_free_physmem_slot(struct 
>> kvm_memory_slot *free,
>>      if (!dont || free->lpage_info != dont->lpage_info)
>>          vfree(free->lpage_info);
>>  
>> -    free->npages = 0;
>>      free->dirty_bitmap = NULL;
>>      free->rmap = NULL;
>>      free->lpage_info = NULL;
>> +
>> +#ifdef CONFIG_X86
>> +    update_alias_slots(kvm, free);
>> +    if (dont)
>> +        update_alias_slots(kvm, dont);
>> +#endif
>> +    free->npages = 0;
>>     
>
> Why is this needed? I don't understand when would you free a memslot
> without freeing any aliases that map it first?
>
>   
(sent it already, but for some reason it didnt reach to the mailing list)
beacuse in case of dont != NULL, we actually dont free the memslot...