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Re: [Qemu-devel] [PATCH 12/15] s390x: reduce TARGET_PHYS_ADDR_SPACE_BITS
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 12/15] s390x: reduce TARGET_PHYS_ADDR_SPACE_BITS to 62 |
Date: |
Mon, 27 May 2013 14:52:17 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 |
Am 27.05.2013 09:28, schrieb Paolo Bonzini:
> Il 26/05/2013 23:08, Christian Borntraeger ha scritto:
>> On 26/05/13 21:07, Paolo Bonzini wrote:
>>> Il 26/05/2013 16:14, Andreas Färber ha scritto:
>>>>> With the next patch, the memory API will complain if the
>>>>> TARGET_PHYS_ADDR_SPACE_BITS gets dangerously close to an
>>>>> overflow. s390x can handle up to 64 bit of physical address
>>>>> space from its page tables, but we never use that much. Just
>>>>> decrease the value.
>>>>>
>>>>> Cc: Alexander Graf <address@hidden>
>>>>> Signed-off-by: Paolo Bonzini <address@hidden>
[...]
>> I would prefer to allow 64bit of address space. Memory on s390x can be
>> discontiguous. It is currently not used under KVM and it might not make
>> a lot of sense, but the current KVM code would allow a guest that has a
>> layout of lets say 0...1GB + 16EB-1GB...16EB.
>>
>> Furthermore, I know of some (prototype only) hw memory devices that actually
>> populated the upper memory addresses. If such a thing becomes reality in the
>> future we cannot provide virtualization of those.
>
> Ok, I'll drop this patch and the next one from the pull request.
It has already been merged, that's how I became aware of it:
http://git.qemu.org/?p=qemu.git;a=commit;h=fd469df97ab4277411ecdd4032a2f045a3a87b2a
Note that Alex is currently absent, so please CC some of the other s390x
folks or wait for an ack if you plan alternative changes.
Cheers,
Andreas
--
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
- [Qemu-devel] [PATCH 07/15] memory: Replace open-coded memory_region_is_romd, (continued)
- [Qemu-devel] [PATCH 07/15] memory: Replace open-coded memory_region_is_romd, Paolo Bonzini, 2013/05/24
- [Qemu-devel] [PATCH 08/15] memory: Rename readable flag to romd_mode, Paolo Bonzini, 2013/05/24
- [Qemu-devel] [PATCH 09/15] memory: do not duplicate memory_region_destructor_none, Paolo Bonzini, 2013/05/24
- [Qemu-devel] [PATCH 10/15] memory: make memory_global_sync_dirty_bitmap take an AddressSpace, Paolo Bonzini, 2013/05/24
- [Qemu-devel] [PATCH 11/15] memory: fix address space initialization/destruction, Paolo Bonzini, 2013/05/24
- [Qemu-devel] [PATCH 12/15] s390x: reduce TARGET_PHYS_ADDR_SPACE_BITS to 62, Paolo Bonzini, 2013/05/24
[Qemu-devel] [PATCH 13/15] memory: limit sections in the radix tree to the actual address space size, Paolo Bonzini, 2013/05/24
[Qemu-devel] [PATCH 14/15] memory: populate FlatView for new address spaces, Paolo Bonzini, 2013/05/24
[Qemu-devel] [PATCH 15/15] memory: clean up phys_page_find, Paolo Bonzini, 2013/05/24
Re: [Qemu-devel] [PULL 00/15] IOMMU patches for 1.6, part 1, Paolo Bonzini, 2013/05/27