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Re: [Qemu-devel] [PATCH v7 5/7] memory: make mmio dispatch able to be ou
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH v7 5/7] memory: make mmio dispatch able to be out of biglock |
Date: |
Mon, 06 May 2013 13:25:26 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2013-05-06 13:21, Paolo Bonzini wrote:
> Il 25/11/2012 03:03, Liu Ping Fan ha scritto:
>> @@ -3550,12 +3668,11 @@ void *address_space_map(AddressSpace *as,
>> target_phys_addr_t *plen,
>> bool is_write)
>> {
>> - AddressSpaceDispatch *d = as->dispatch;
>> target_phys_addr_t len = *plen;
>> target_phys_addr_t todo = 0;
>> int l;
>> target_phys_addr_t page;
>> - MemoryRegionSection *section;
>> + MemoryRegionSection *section, mr_obj;
>> ram_addr_t raddr = RAM_ADDR_MAX;
>> ram_addr_t rlen;
>> void *ret;
>> @@ -3565,7 +3682,8 @@ void *address_space_map(AddressSpace *as,
>> l = (page + TARGET_PAGE_SIZE) - addr;
>> if (l > len)
>> l = len;
>> - section = phys_page_find(d, page >> TARGET_PAGE_BITS);
>> + address_space_section_lookup_ref(as, page >> TARGET_PAGE_BITS,
>> &mr_obj);
>> + section = &mr_obj;
>>
>> if (!(memory_region_is_ram(section->mr) && !section->readonly)) {
>> if (todo || bounce.buffer) {
>> @@ -3579,6 +3697,7 @@ void *address_space_map(AddressSpace *as,
>> }
>>
>> *plen = l;
>> + memory_region_section_unref(&mr_obj);
>> return bounce.buffer;
>> }
>> if (!todo) {
>> @@ -3589,6 +3708,7 @@ void *address_space_map(AddressSpace *as,
>> len -= l;
>> addr += l;
>> todo += l;
>> + memory_region_section_unref(&mr_obj);
>> }
>> rlen = todo;
>> ret = qemu_ram_ptr_length(raddr, &rlen);
>
> I think this unref is wrong. You need to delay it to the
> address_space_unmap, and this in turns requires changing the signature
> of address_space_map.
Can't RAMBlock hold a reference to the associated region? Then this
could be retrieved on unmap without bothering the caller.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux