* [PATCH] kvm: mirror "-machine dirty_gfn_count" to the accelerator property
@ 2021-01-08 19:08 huangy81
2021-01-08 20:41 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: huangy81 @ 2021-01-08 19:08 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, Hyman, peterx
QEMU enable the dirty ring feature by specifing the "-accel" sub-parameter.
https://lore.kernel.org/qemu-devel/20210108165050.406906-10-peterx@redhat.com/
Libvirt use "-machine accel=kvm" option to specify the accelerator by default,
which is incompatible with above option.
This patch introduce the "dirty_gfn_count" sub-parameter of the "-machine"
in the way that the commit "23b089" has done. So that Libvirt can enable this
feature by adding "-machine dirty_gfn_count=xxx" to the QEMU command line.
Signed-off-by: Hyman <huangy81@chinatelecom.cn>
---
softmmu/vl.c | 3 ++-
util/qemu-config.c | 4 ++++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 7ddf405..d8e3dec 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1666,7 +1666,8 @@ static int machine_set_property(void *opaque,
object_register_sugar_prop(ACCEL_CLASS_NAME("xen"), qom_name, value);
return 0;
}
- if (g_str_equal(qom_name, "kvm-shadow-mem")) {
+ if (g_str_equal(qom_name, "kvm-shadow-mem") ||
+ g_str_equal(qom_name, "dirty-gfn-count")) {
object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), qom_name, value);
return 0;
}
diff --git a/util/qemu-config.c b/util/qemu-config.c
index e2a700b..70f1b50 100644
--- a/util/qemu-config.c
+++ b/util/qemu-config.c
@@ -234,6 +234,10 @@ static QemuOptsList machine_opts = {
.help = "Up to 8 chars in set of [A-Za-z0-9. ](lower case chars"
" converted to upper case) to pass to machine"
" loader, boot manager, and guest kernel",
+ },{
+ .name = "dirty_gfn_count",
+ .type = QEMU_OPT_NUMBER,
+ .help = "KVM dirty ring GFN count",
},
{ /* End of list */ }
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] kvm: mirror "-machine dirty_gfn_count" to the accelerator property
2021-01-08 19:08 [PATCH] kvm: mirror "-machine dirty_gfn_count" to the accelerator property huangy81
@ 2021-01-08 20:41 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-01-08 20:41 UTC (permalink / raw)
To: huangy81, qemu-devel; +Cc: peterx
On 08/01/21 20:08, huangy81@chinatelecom.cn wrote:
> QEMU enable the dirty ring feature by specifing the "-accel" sub-parameter.
> https://lore.kernel.org/qemu-devel/20210108165050.406906-10-peterx@redhat.com/
> Libvirt use "-machine accel=kvm" option to specify the accelerator by default,
> which is incompatible with above option.
>
> This patch introduce the "dirty_gfn_count" sub-parameter of the "-machine"
> in the way that the commit "23b089" has done. So that Libvirt can enable this
> feature by adding "-machine dirty_gfn_count=xxx" to the QEMU command line.
>
> Signed-off-by: Hyman <huangy81@chinatelecom.cn>
Libvirt should switch to "-accel kvm" instead. The "-machine" options
for accelerators are legacy and now there is a better mechanism. There
will never be a version of QEMU that supports dirty ring and doesn't
support "-accel kvm", so it's easy for Libvirt to detect when to use
"-accel".
Paolo
> ---
> softmmu/vl.c | 3 ++-
> util/qemu-config.c | 4 ++++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index 7ddf405..d8e3dec 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -1666,7 +1666,8 @@ static int machine_set_property(void *opaque,
> object_register_sugar_prop(ACCEL_CLASS_NAME("xen"), qom_name, value);
> return 0;
> }
> - if (g_str_equal(qom_name, "kvm-shadow-mem")) {
> + if (g_str_equal(qom_name, "kvm-shadow-mem") ||
> + g_str_equal(qom_name, "dirty-gfn-count")) {
> object_register_sugar_prop(ACCEL_CLASS_NAME("kvm"), qom_name, value);
> return 0;
> }
> diff --git a/util/qemu-config.c b/util/qemu-config.c
> index e2a700b..70f1b50 100644
> --- a/util/qemu-config.c
> +++ b/util/qemu-config.c
> @@ -234,6 +234,10 @@ static QemuOptsList machine_opts = {
> .help = "Up to 8 chars in set of [A-Za-z0-9. ](lower case chars"
> " converted to upper case) to pass to machine"
> " loader, boot manager, and guest kernel",
> + },{
> + .name = "dirty_gfn_count",
> + .type = QEMU_OPT_NUMBER,
> + .help = "KVM dirty ring GFN count",
> },
> { /* End of list */ }
> }
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-01-08 20:41 ` Paolo Bonzini
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