From: Paolo Bonzini <pbonzini@redhat.com>
To: "Andreas Färber" <afaerber@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Alexander Graf <agraf@suse.de>,
qemu-devel@nongnu.org, Avi Kivity <avi.kivity@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 12/15] s390x: reduce TARGET_PHYS_ADDR_SPACE_BITS to 62
Date: Sun, 26 May 2013 21:07:12 +0200 [thread overview]
Message-ID: <51A25D60.9000502@redhat.com> (raw)
In-Reply-To: <51A218DF.2070506@suse.de>
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 <agraf@suse.de>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Didn't Avi introduce 128-bit arithmetic into QEMU to avoid 64-bit values
> overflowing? Why are you limiting Memory API to 62-bit now?
The next patch makes a difference between artificial memory regions
(containers and aliases) which can have arbitrary placement and width,
and the final view of the address space which cannot have a full 64-bit
size.
63 bits probably would work, but I preferred to be safe since 62 is the
largest used by other targets.
It should be fixable, but if it is not a problem I wouldn't worry much
about it.
Paolo
next prev parent reply other threads:[~2013-05-26 19:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-24 17:02 [Qemu-devel] [PULL 00/15] IOMMU patches for 1.6, part 1 Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 01/15] exec: remove obsolete comment Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 02/15] exec: eliminate qemu_put_ram_ptr Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 03/15] exec: make qemu_get_ram_ptr private Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 04/15] exec: eliminate stq_phys_notdirty Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 05/15] memory: assert that PhysPageEntry's ptr does not overflow Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 06/15] memory: allow memory_region_find() to run on non-root memory regions Paolo Bonzini
2013-05-24 17:02 ` [Qemu-devel] [PATCH 07/15] memory: Replace open-coded memory_region_is_romd Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 08/15] memory: Rename readable flag to romd_mode Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 09/15] memory: do not duplicate memory_region_destructor_none Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 10/15] memory: make memory_global_sync_dirty_bitmap take an AddressSpace Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 11/15] memory: fix address space initialization/destruction Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 12/15] s390x: reduce TARGET_PHYS_ADDR_SPACE_BITS to 62 Paolo Bonzini
2013-05-26 14:14 ` Andreas Färber
2013-05-26 19:07 ` Paolo Bonzini [this message]
2013-05-26 21:08 ` Christian Borntraeger
2013-05-27 7:28 ` Paolo Bonzini
2013-05-27 12:52 ` Andreas Färber
2013-05-27 13:13 ` Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 13/15] memory: limit sections in the radix tree to the actual address space size Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 14/15] memory: populate FlatView for new address spaces Paolo Bonzini
2013-05-24 17:03 ` [Qemu-devel] [PATCH 15/15] memory: clean up phys_page_find Paolo Bonzini
2013-05-27 8:13 ` [Qemu-devel] [PULL 00/15] IOMMU patches for 1.6, part 1 Paolo Bonzini
2013-06-17 21:18 ` Anthony Liguori
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