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Re: [Qemu-devel] [PATCH v2] accel: default to an actually available acce
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [PATCH v2] accel: default to an actually available accelerator |
Date: |
Wed, 13 Sep 2017 19:39:48 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 13.09.2017 19:29, Cornelia Huck wrote:
> configure_accelerator() falls back to tcg if no accelerator has
> been specified. Formerly, we could be sure that tcg is always
> available; however, with --disable-tcg, this is not longer true,
> and you are not able to start qemu without explicitly specifying
> another accelerator on those builds.
>
> Instead, choose an accelerator in the order tcg->kvm->hax.
>
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
> RFC->v2:
> - drop xen from the list of fallbacks
> - use comma-delimited list of accelerators (much easier)
> - changed one place in qemu-options.hx that had been missed
> ---
> accel/accel.c | 3 +--
> qemu-options.hx | 8 +++++---
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/accel/accel.c b/accel/accel.c
> index 8ae40e1e13..e8a3121d06 100644
> --- a/accel/accel.c
> +++ b/accel/accel.c
> @@ -79,8 +79,7 @@ void configure_accelerator(MachineState *ms)
>
> accel = qemu_opt_get(qemu_get_machine_opts(), "accel");
> if (accel == NULL) {
> - /* Use the default "accelerator", tcg */
> - accel = "tcg";
> + accel = "tcg:kvm:hax";
> }
>
> p = accel;
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 9f6e2adfff..2ff88389e0 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -31,7 +31,7 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
> "-machine [type=]name[,prop[=value][,...]]\n"
> " selects emulated machine ('-machine help' for list)\n"
> " property accel=accel1[:accel2[:...]] selects
> accelerator\n"
> - " supported accelerators are kvm, xen, hax or tcg
> (default: tcg)\n"
> + " supported accelerators are kvm, xen, hax or tcg
> (default: tcg:kvm:hax)\n"
> " kernel_irqchip=on|off|split controls accelerated
> irqchip support (default=off)\n"
> " vmport=on|off|auto controls emulation of vmport
> (default: auto)\n"
> " kvm_shadow_mem=size of KVM shadow MMU in bytes\n"
> @@ -66,7 +66,8 @@ Supported machine properties are:
> @table @option
> @item address@hidden:@var{accels2}[:...]]
> This is used to enable an accelerator. Depending on the target architecture,
> -kvm, xen, hax or tcg can be available. By default, tcg is used. If there is
> +kvm, xen, hax or tcg can be available. By default, the first one available
> +out of tcg, kvm, hax (in that order) is used. If there is
> more than one accelerator specified, the next one is used if the previous one
> fails to initialize.
> @item kernel_irqchip=on|off
> @@ -126,7 +127,8 @@ STEXI
> @item -accel @var{name}[,address@hidden,...]]
> @findex -accel
> This is used to enable an accelerator. Depending on the target architecture,
> -kvm, xen, hax or tcg can be available. By default, tcg is used. If there is
> +kvm, xen, hax or tcg can be available. By default, the first one available
> +out of tcg, kvm, hax (in that order) is used. If there is
> more than one accelerator specified, the next one is used if the previous one
> fails to initialize.
> @table @option
Reviewed-by: Thomas Huth <address@hidden>