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Re: [Qemu-devel] [PATCH RFC 08/13] range: add Range structure
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH RFC 08/13] range: add Range structure |
Date: |
Tue, 14 May 2013 10:55:51 +0300 |
On Mon, May 13, 2013 at 09:20:08PM +0100, Peter Maydell wrote:
> On 13 May 2013 21:01, Michael S. Tsirkin <address@hidden> wrote:
> > Sometimes we need to pass ranges around, add a
> > handy structure for this purpose.
> >
> > Signed-off-by: Michael S. Tsirkin <address@hidden>
> > ---
> > include/qemu/range.h | 22 ++++++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git a/include/qemu/range.h b/include/qemu/range.h
> > index 3502372..4bcd346 100644
> > --- a/include/qemu/range.h
> > +++ b/include/qemu/range.h
> > @@ -1,6 +1,28 @@
> > #ifndef QEMU_RANGE_H
> > #define QEMU_RANGE_H
> >
> > +#include <inttypes.h>
> > +
> > +/*
> > + * Operations on 64 address ranges.
>
> missing "bit" ?
>
> > + * Notes:
> > + * - ranges must not wrap around 0, but can include the last byte ~0x0LL.
> > + * - this can not represent a full 0 to ~0x0LL range.
> > + */
> > +
> > +/* A structure representing a range of addresses. */
> > +struct Range {
> > + uint64_t begin; /* First byte of the range, or 0 if empty. */
> > + uint64_t end; /* 1 + the last byte. 0 if range empty or ends at
> > ~0x0LL. */
> > +};
> > +typedef struct Range Range;
> > +
> > +/* verify that range is not empty and does not overlap */
>
> Doesn't overlap what?
I meant wrap around there.
> Why isn't an empty range valid?
> The struct definition above says it's OK.
Yes it's a bad name. Should be range_non_empty or something.
> > +{
> > + return range->begin + 1 <= range->end;
> > +}
>
> I note that memory.c defines its own concept of an AddrRange.
>
> thanks
> -- PMM
Good point, maybe I'll reuse that or just use two 64 bit fields explicitly.
--
MST
- [Qemu-devel] [PATCH RFC 02/13] hw/i386/pc.c: move IO_APIC_DEFAULT_ADDRESS to include/hw/i386/apic.h, (continued)
- [Qemu-devel] [PATCH RFC 02/13] hw/i386/pc.c: move IO_APIC_DEFAULT_ADDRESS to include/hw/i386/apic.h, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 01/13] apic: rename apic specific bitopts, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 04/13] fw_cfg: move typedef to qemu/typedefs.h, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 06/13] acpi: add rules to compile ASL source, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 05/13] i386: add ACPI table files from seabios, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 08/13] range: add Range structure, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 13/13] pc: reuse guest info for legacy fw cfg, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 09/13] i386: add bios linker/loader, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 07/13] acpi: pre-compiled ASL files, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 10/13] i386: generate pc guest info, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 11/13] pc: pass PCI hole ranges to Guests, Michael S. Tsirkin, 2013/05/13
- [Qemu-devel] [PATCH RFC 12/13] i386: ACPI table generation code from seabios, Michael S. Tsirkin, 2013/05/13