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Re: [Qemu-devel] [RFC][PATCH 11/15] memory: Allow unaligned address_spac
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [RFC][PATCH 11/15] memory: Allow unaligned address_space_rw |
Date: |
Mon, 06 May 2013 16:58:46 +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 16:55, Paolo Bonzini wrote:
> Il 06/05/2013 16:26, Jan Kiszka ha scritto:
>> This will be needed for some corner cases with para-virtual the I/O
>> ports.
>>
>> Signed-off-by: Jan Kiszka <address@hidden>
>> ---
>> exec.c | 33 ++++++++++++++++++---------------
>> 1 files changed, 18 insertions(+), 15 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 3ee1f3f..9c582b1 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1833,38 +1833,41 @@ void address_space_rw(AddressSpace *as, hwaddr addr,
>> uint8_t *buf,
>> uint8_t *ptr;
>> uint32_t val;
>> MemoryRegionSection *section;
>> + MemoryRegion *mr;
>>
>> while (len > 0) {
>> l = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
>> if (l > len)
>> l = len;
>> section = address_space_lookup_region(as, addr);
>> + mr = section->mr;
>>
>> if (is_write) {
>> - if (!memory_region_is_ram(section->mr)) {
>> + if (!memory_region_is_ram(mr)) {
>> hwaddr addr1;
>> addr1 = memory_region_section_addr(section, addr);
>> /* XXX: could force cpu_single_env to NULL to avoid
>> potential bugs */
>> - if (l >= 4 && ((addr1 & 3) == 0)) {
>> + if (l >= 4 && ((addr1 & 3) == 0 ||
>> mr->ops->impl.unaligned)) {
>
> Does the length matter at all if unaligned accesses are allowed? I
> think it shouldn't...
What do you mean? The length test here is not about alignment, it's
about proper split-up depending on the input size (we cannot use 32 bit
for all accesses and do not want to make them all byte accesses, do we?).
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] [RFC][PATCH 10/15] memory: Rework sub-page handling, (continued)
[Qemu-devel] [RFC][PATCH 08/15] isa: implement isa_is_ioport_assigned via memory_region_find, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 11/15] memory: Allow unaligned address_space_rw, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 09/15] memory: Introduce address_space_lookup_region, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 07/15] Privatize register_ioport_read/write, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 01/15] adlib: replace register_ioport*, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 04/15] i82374: replace register_ioport*, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 15/15] ioport: Move IOPortRead/WriteFunc typedefs to memory.h, Jan Kiszka, 2013/05/06
[Qemu-devel] [RFC][PATCH 13/15] ioport: Switch dispatching to memory core layer, Jan Kiszka, 2013/05/06