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Re: [Qemu-devel] [RFC v2 04/32] qemu_ram_block_host_offset
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC v2 04/32] qemu_ram_block_host_offset |
Date: |
Fri, 25 Aug 2017 16:28:07 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
* Philippe Mathieu-Daudé (address@hidden) wrote:
> Hi David,
>
> On 08/24/2017 04:27 PM, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Utility to give the offset of a host pointer within a RAMBlock
> > (assuming we already know it's in that RAMBlock)
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> > exec.c | 10 ++++++++++
> > include/exec/cpu-common.h | 1 +
> > 2 files changed, 11 insertions(+)
> >
> > diff --git a/exec.c b/exec.c
> > index 67df2909ce..35b4cea2ed 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -2231,6 +2231,16 @@ static void *qemu_ram_ptr_length(RAMBlock
> > *ram_block, ram_addr_t addr,
> > return ramblock_ptr(block, addr);
> > }
> > +/* Return the offset of a hostpointer within a ramblock */
> > +ram_addr_t qemu_ram_block_host_offset(RAMBlock *rb, void *host)
> > +{
> > + ram_addr_t res = (uint8_t *)host - (uint8_t *)rb->host;
>
> What about using ptrdiff_t here,
We tend to use ram_addr_t for offsets in RAM, and so that's
the return type of the function, and we're also comparing this
value to rb->max_length below which is also a ram_addr_t.
> > + assert((uint8_t *)host >= (uint8_t *)rb->host);
>
> and uintptr_t here?
Done.
Thanks,
Dave
> > + assert(res < rb->max_length);
> > +
> > + return res;
> > +}
> > +
> > /*
> > * Translates a host ptr back to a RAMBlock, a ram_addr and an offset
> > * in that RAMBlock.
> > diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> > index 74341b19d2..0d861a6289 100644
> > --- a/include/exec/cpu-common.h
> > +++ b/include/exec/cpu-common.h
> > @@ -68,6 +68,7 @@ ram_addr_t qemu_ram_addr_from_host(void *ptr);
> > RAMBlock *qemu_ram_block_by_name(const char *name);
> > RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset,
> > ram_addr_t *offset);
> > +ram_addr_t qemu_ram_block_host_offset(RAMBlock *rb, void *host);
> > void qemu_ram_set_idstr(RAMBlock *block, const char *name, DeviceState
> > *dev);
> > void qemu_ram_unset_idstr(RAMBlock *block);
> > const char *qemu_ram_get_idstr(RAMBlock *rb);
> >
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [RFC v2 00/32] postcopy+vhost-user/shared ram, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 02/32] vhub: Only process received packets on started queues, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 01/32] vhu: vu_queue_started, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 03/32] migrate: Update ram_block_discard_range for shared, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 04/32] qemu_ram_block_host_offset, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 05/32] migration/ram: ramblock_recv_bitmap_test_byte_offset, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 06/32] postcopy: use UFFDIO_ZEROPAGE only when available, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 07/32] postcopy: Add notifier chain, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 08/32] postcopy: Add vhost-user flag for postcopy and check it, Dr. David Alan Gilbert (git), 2017/08/24
- [Qemu-devel] [RFC v2 09/32] vhost-user: Add 'VHOST_USER_POSTCOPY_ADVISE' message, Dr. David Alan Gilbert (git), 2017/08/24