On 08/11/2011 09:58 AM, Stefan Hajnoczi wrote:
On Thu, Aug 04, 2011 at 07:14:43PM +0200, Paolo Bonzini wrote:
These helpers do a full transfer from an in-memory buffer to
target memory, with full support for MMIO areas. It will be used to store
the reply of an emulated command into a QEMUSGList provided by the
adapter.
Signed-off-by: Paolo Bonzini<pbonz...@redhat.com>
---
cutils.c | 8 +++---
dma-helpers.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
dma.h | 5 ++++
3 files changed, 72 insertions(+), 4 deletions(-)
I don't understand this patch. If we have a memory buffer that needs to
be transferred to target memory, then there is no need for bounce
buffers or cpu_physical_memory_map().
Can we use cpu_physical_memory_rw() on each sglist element instead? No
-EAGAIN necessary because the memory buffer already acts as the local
bounce buffer.
Doh, you're obviously right. I don't know what I was thinking. :)
What do you think about passing the residual bytes for short transfers?
Should I look into updating BlockDriverCompletionFunc, or is the
approach of patch 2 okay? If I have an excuse to learn more about
Coccinelle, that can be fun. :)
Paolo
