[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 2/3] s390x/pci: fixup global refresh
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] s390x/pci: fixup global refresh |
Date: |
Wed, 31 Jan 2018 12:35:33 +0100 |
On Tue, 30 Jan 2018 10:47:14 +0100
Yi Min Zhao <address@hidden> wrote:
> The VFIO common code doesn't provide the possibility to modify a
> previous mapping entry in another way than unmapping and mapping again
> with new properties.
I'm wondering why other architectures don't need that. Is this
refreshing an unique ability on s390 (due to that instruction)?
>
> To avoid -EEXIST DMA mapping error, this we introduce a GHashTable to
s/this//
> store S390IOTLBEntry instances in order to cache the mapped entries.
> When intercepting rpcit instruction, ignore the identical mapped
> entries to avoid doing map operations multiple times and do unmap and
> re-map operations for the case of updating the valid entries. To
> achieve that goal, we also export the DMA walking function and
> optimize the code handling errors in rpcit handler.
How often does such a thing happen in practice?
>
> Acked-by: Pierre Morel <address@hidden>
> Signed-off-by: Yi Min Zhao <address@hidden>
> ---
> hw/s390x/s390-pci-bus.c | 28 +++++++++-----
> hw/s390x/s390-pci-bus.h | 3 ++
> hw/s390x/s390-pci-inst.c | 95
> ++++++++++++++++++++++++++++++++++--------------
> 3 files changed, 90 insertions(+), 36 deletions(-)
Can't really review the rest due to -ENODOC, sorry.