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Re: [Qemu-devel] [Qemu-ppc] [RFC] pseries: Enable in-kernel H_LOGICAL_CI
From: |
Nikunj A Dadhania |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations |
Date: |
Tue, 03 Feb 2015 14:26:44 +0530 |
User-agent: |
Notmuch/0.17+27~gae47d61 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-redhat-linux-gnu) |
David Gibson <address@hidden> writes:
> qemu currently implements the hypercalls H_LOGICAL_CI_LOAD and
> H_LOGICAL_CI_STORE as PAPR extensions. These are used by the SLOF firmware
> for IO, because performing cache inhibited MMIO accesses with the MMU off
> (real mode) is very awkward on POWER.
>
> This approach breaks when SLOF needs to access IO devices implemented
> within KVM instead of in qemu. The simplest example would be virtio-blk
> using an iothread, because the iothread / dataplane mechanism relies on
> an in-kernel implementation of the virtio queue notification MMIO.
>
> To fix this, an in-kernel implementation of these hypercalls has been made,
> however, the hypercalls still need to be enabled from qemu. This performs
> the necessary calls to do so.
>
> Signed-off-by: David Gibson <address@hidden>
Reviewed-by: Nikunj A Dadhania <address@hidden>
- [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/03
- Re: [Qemu-devel] [Qemu-ppc] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations,
Nikunj A Dadhania <=
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, Paul Mackerras, 2015/02/03
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/03
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, Alexander Graf, 2015/02/04
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/04
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, Alexander Graf, 2015/02/04
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/04
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, Alexander Graf, 2015/02/05
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/05
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, Alexander Graf, 2015/02/05
- Re: [Qemu-devel] [RFC] pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations, David Gibson, 2015/02/05