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Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board |
Date: |
Tue, 09 Dec 2014 10:31:08 +0100 |
Hi,
> So... after playing with this thing for some time, it's become clear
> that "MMIO traps" are painfully slow on the aarch64 platform we've been
> working on (using KVM).
So, as we don't have compatibility requirements, and we also can't play
tricks like using x86 string instructions: How about a completely
different, dma-style interface for fw_cfg access?
One register for the (physical) target address.
One register for the transfer size.
One register for the fw_cfg entry.
Possibly one register for the fw_cfg offset (not really needed, but
avoids the need for side effects such as writing fw_cfg entry register
clearing the offset).
One register to kick the transfer.
cheers,
Gerd
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, (continued)
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Peter Maydell, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Peter Maydell, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Peter Maydell, 2014/12/08
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/08
Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Christopher Covington, 2014/12/08
Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board,
Gerd Hoffmann <=
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/09
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Peter Maydell, 2014/12/09
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Richard W.M. Jones, 2014/12/09
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Paolo Bonzini, 2014/12/10
- Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Andrew Jones, 2014/12/10
Re: [Qemu-devel] [PATCH v2] arm: add fw_cfg to "virt" board, Laszlo Ersek, 2014/12/08