Dear xen maintainers,
here are three patches to update the xen config fragments to the currently
existing configs.
The fourth patch is just an addition to MAINTAINERS that I saw reasonable
after get_maintainers did not point to the XEN subsystem.
It applies cleanly on next-20220810.
Lukas
Lukas Bulwahn (4):
xen: x86: set the config XEN_512GB after config change
xen: remove XEN_SCRUB_PAGES in xen.config
xen: move XEN_BALLOON_MEMORY_HOTPLUG to generic config
MAINTAINERS: add xen config fragments to XEN HYPERVISOR sections
MAINTAINERS | 2 ++
arch/x86/configs/xen.config | 5 +----
kernel/configs/xen.config | 2 +-
3 files changed, 4 insertions(+), 5 deletions(-)
--
2.17.1
While reviewing arch/x86/configs/xen.config, I noticed the following
note in this file:
'# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
'# move to generic config if it ever does.
CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
Commit 6c6685055a28 ("kconfig: add xenconfig defconfig helper") in June
2015 adds this note. Fortunately, commit 4ab215061554 ("arm64: Add memory
hotplug support") from December 2018 adds the memory hotplug in arm64, so
the precondition of this note above is now met.
Move setting the config XEN_BALLOON_MEMORY_HOTPLUG into the generic
xen.config now.
Signed-off-by: Lukas Bulwahn <[email protected]>
---
arch/x86/configs/xen.config | 3 ---
kernel/configs/xen.config | 1 +
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/x86/configs/xen.config b/arch/x86/configs/xen.config
index 8a6c88f48e75..024817bc4f0e 100644
--- a/arch/x86/configs/xen.config
+++ b/arch/x86/configs/xen.config
@@ -23,6 +23,3 @@ CONFIG_XEN_ACPI_PROCESSOR=m
CONFIG_XEN_PCIDEV_BACKEND=m
# x86 specific frontend drivers
CONFIG_XEN_PCIDEV_FRONTEND=m
-# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
-# move to generic config if it ever does.
-CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
index 436f806aa1ed..ea84d5b3122d 100644
--- a/kernel/configs/xen.config
+++ b/kernel/configs/xen.config
@@ -34,6 +34,7 @@ CONFIG_INPUT_XEN_KBDDEV_FRONTEND=m
CONFIG_XEN_SCSI_FRONTEND=m
# others
CONFIG_XEN_BALLOON=y
+CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
CONFIG_XEN_DEV_EVTCHN=m
CONFIG_XEN_BLKDEV_FRONTEND=m
CONFIG_XEN_NETDEV_FRONTEND=m
--
2.17.1
On 10.08.22 08:07, Lukas Bulwahn wrote:
Hello Lukas, all
> While reviewing arch/x86/configs/xen.config, I noticed the following
> note in this file:
>
> '# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
> '# move to generic config if it ever does.
> CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
>
> Commit 6c6685055a28 ("kconfig: add xenconfig defconfig helper") in June
> 2015 adds this note. Fortunately, commit 4ab215061554 ("arm64: Add memory
> hotplug support") from December 2018 adds the memory hotplug in arm64, so
> the precondition of this note above is now met.
>
> Move setting the config XEN_BALLOON_MEMORY_HOTPLUG into the generic
> xen.config now.
I might have missed something but I have never heard of anyone using
XEN_BALLOON_MEMORY_HOTPLUG on Arm.
Looking into the code, I am afraid, CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
won't be functional on Arm without reworking resource allocation logic
in drivers/xen/ballon.c at least, since system "iomem_resource" cannot
be used on Arm to allocate unused memory region(s), please see
additional_memory_resource(). I might be wrong, but it feels to me that
here we would need a similar logic like in
drivers/xen/unpopulated-alloc.c which is functional on Arm since it uses
specific Xen resource (on x86 it is just an iomem_resource, but on Arm
it contains provided by the hypervisor extended regions).
I am not aware of anyone working on it, so I wouldn't enable that
support on Arm by default until the code is updated.
>
> Signed-off-by: Lukas Bulwahn <[email protected]>
> ---
> arch/x86/configs/xen.config | 3 ---
> kernel/configs/xen.config | 1 +
> 2 files changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/arch/x86/configs/xen.config b/arch/x86/configs/xen.config
> index 8a6c88f48e75..024817bc4f0e 100644
> --- a/arch/x86/configs/xen.config
> +++ b/arch/x86/configs/xen.config
> @@ -23,6 +23,3 @@ CONFIG_XEN_ACPI_PROCESSOR=m
> CONFIG_XEN_PCIDEV_BACKEND=m
> # x86 specific frontend drivers
> CONFIG_XEN_PCIDEV_FRONTEND=m
> -# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
> -# move to generic config if it ever does.
> -CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
> diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
> index 436f806aa1ed..ea84d5b3122d 100644
> --- a/kernel/configs/xen.config
> +++ b/kernel/configs/xen.config
> @@ -34,6 +34,7 @@ CONFIG_INPUT_XEN_KBDDEV_FRONTEND=m
> CONFIG_XEN_SCSI_FRONTEND=m
> # others
> CONFIG_XEN_BALLOON=y
> +CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
> CONFIG_XEN_DEV_EVTCHN=m
> CONFIG_XEN_BLKDEV_FRONTEND=m
> CONFIG_XEN_NETDEV_FRONTEND=m
--
Regards,
Oleksandr Tyshchenko
On Wed, Aug 10, 2022 at 1:32 PM Oleksandr Tyshchenko
<[email protected]> wrote:
>
>
> On 10.08.22 08:07, Lukas Bulwahn wrote:
>
> Hello Lukas, all
>
> > While reviewing arch/x86/configs/xen.config, I noticed the following
> > note in this file:
> >
> > '# depends on MEMORY_HOTPLUG, arm64 doesn't enable this yet,
> > '# move to generic config if it ever does.
> > CONFIG_XEN_BALLOON_MEMORY_HOTPLUG=y
> >
> > Commit 6c6685055a28 ("kconfig: add xenconfig defconfig helper") in June
> > 2015 adds this note. Fortunately, commit 4ab215061554 ("arm64: Add memory
> > hotplug support") from December 2018 adds the memory hotplug in arm64, so
> > the precondition of this note above is now met.
> >
> > Move setting the config XEN_BALLOON_MEMORY_HOTPLUG into the generic
> > xen.config now.
>
>
> I might have missed something but I have never heard of anyone using
> XEN_BALLOON_MEMORY_HOTPLUG on Arm.
>
> Looking into the code, I am afraid, CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
> won't be functional on Arm without reworking resource allocation logic
> in drivers/xen/ballon.c at least, since system "iomem_resource" cannot
> be used on Arm to allocate unused memory region(s), please see
> additional_memory_resource(). I might be wrong, but it feels to me that
> here we would need a similar logic like in
> drivers/xen/unpopulated-alloc.c which is functional on Arm since it uses
> specific Xen resource (on x86 it is just an iomem_resource, but on Arm
> it contains provided by the hypervisor extended regions).
>
> I am not aware of anyone working on it, so I wouldn't enable that
> support on Arm by default until the code is updated.
>
Thanks for the in-depth investigation and explanation. For now, let us
drop this patch here and keep the configs as they are.
Lukas