[Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Cédric Le Goater]

PowerNV (as Non-Virtualized) is the "baremetal" platform using the
OPAL [1] firmware. It runs Linux on IBM and OpenPOWER systems and can
be used as an hypervisor OS, running KVM guests, or simply as a host
OS. OPAL includes a Linux kernel and a buildroot rootfs which acts as
a bootloader [2] for the various systems installed on disks.

Since QEMU provides PowerNV machines for POWER8-10 processors [3], add
a new qemu_ppc64le_powernv board to buildroot.

[1] https://github.com/open-power/skiboot/blob/master/doc/overview.rst
[2] https://github.com/open-power/petitboot/
[3] https://qemu.readthedocs.io/en/latest/system/ppc/powernv.html

Cc: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 board/qemu/ppc64le-powernv/readme.txt  |  5 +++++
 configs/qemu_ppc64le_powernv_defconfig | 29 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 board/qemu/ppc64le-powernv/readme.txt
 create mode 100644 configs/qemu_ppc64le_powernv_defconfig

diff --git a/board/qemu/ppc64le-powernv/readme.txt b/board/qemu/ppc64le-powernv/readme.txt
new file mode 100644
index 000000000000..ee102a3d6846
--- /dev/null
+++ b/board/qemu/ppc64le-powernv/readme.txt
@@ -0,0 +1,5 @@
+Run the emulation with:
+
+qemu-system-ppc64 -M powernv9 -kernel vmlinux -append "console=hvc0 rootwait root=/dev/nvme0n1" -device nvme,bus=pcie.3,addr=0x0,drive=drive0,serial=1234 -drive file=./rootfs.ext2,if=none,id=drive0,format=raw,cache=none -device e1000e,netdev=net0,mac=C0:FF:EE:00:01:03,bus=pcie.1,addr=0x0  -netdev user,id=net0 -serial mon:stdio -nographic # qemu_ppc64le_powernv_defconfig
+
+The login prompt will appear in the terminal window.
diff --git a/configs/qemu_ppc64le_powernv_defconfig b/configs/qemu_ppc64le_powernv_defconfig
new file mode 100644
index 000000000000..d8ea6655fce0
--- /dev/null
+++ b/configs/qemu_ppc64le_powernv_defconfig
@@ -0,0 +1,29 @@
+# Architecture
+BR2_powerpc64le=y
+BR2_powerpc_power8=y
+
+# System
+BR2_TARGET_GENERIC_GETTY_PORT="hvc0"
+BR2_SYSTEM_DHCP="eth0"
+
+# Filesystem
+BR2_TARGET_ROOTFS_EXT2=y
+# BR2_TARGET_ROOTFS_TAR is not set
+
+# Image
+BR2_ROOTFS_POST_IMAGE_SCRIPT="board/qemu/post-image.sh"
+BR2_ROOTFS_POST_SCRIPT_ARGS="$(BR2_DEFCONFIG)"
+
+# Linux headers same as kernel
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_15=y
+
+# Kernel
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.15"
+BR2_LINUX_KERNEL_DEFCONFIG="powernv"
+BR2_LINUX_KERNEL_VMLINUX=y
+
+# host-qemu for gitlab testing
+BR2_PACKAGE_HOST_QEMU=y
+BR2_PACKAGE_HOST_QEMU_SYSTEM_MODE=y
-- 
2.31.1

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[Buildroot] [PATCH 2/3] configs/qemu_ppc64_e5500: Enable dhcp on network interface

[Cédric Le Goater]

Add a virtio-net-pci device with a user mode host network backend

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 board/qemu/ppc64-e5500/readme.txt  | 2 +-
 configs/qemu_ppc64_e5500_defconfig | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/board/qemu/ppc64-e5500/readme.txt b/board/qemu/ppc64-e5500/readme.txt
index 61d51f7f4dd0..7c8c80af4458 100644
--- a/board/qemu/ppc64-e5500/readme.txt
+++ b/board/qemu/ppc64-e5500/readme.txt
@@ -1,5 +1,5 @@
 Run the emulation with:
 
- qemu-system-ppc64 -M ppce500 -cpu e5500 -m 256 -kernel output/images/uImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic # qemu_ppc64_e5500_defconfig
+ qemu-system-ppc64 -M ppce500 -cpu e5500 -m 256 -kernel output/images/uImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -net nic,model=virtio-net-pci -net user -append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic # qemu_ppc64_e5500_defconfig
 
 The login prompt will appear in the terminal that started Qemu.
diff --git a/configs/qemu_ppc64_e5500_defconfig b/configs/qemu_ppc64_e5500_defconfig
index 286d79a26b6d..09aac502522b 100644
--- a/configs/qemu_ppc64_e5500_defconfig
+++ b/configs/qemu_ppc64_e5500_defconfig
@@ -2,7 +2,8 @@
 BR2_powerpc64=y
 BR2_powerpc_e5500=y
 
-# Serial port config
+# System
+BR2_SYSTEM_DHCP="eth0"
 BR2_TARGET_GENERIC_GETTY_PORT="ttyS0"
 
 # Image
-- 
2.31.1

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[Buildroot] [PATCH 3/3] configs/qemu_ppc_e500mc: Enable dhcp on network interface

[Cédric Le Goater]

Add a virtio-net-pci device with a user mode host network backend

Cc: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 board/qemu/ppc-e500mc/readme.txt  | 2 +-
 configs/qemu_ppc_e500mc_defconfig | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/board/qemu/ppc-e500mc/readme.txt b/board/qemu/ppc-e500mc/readme.txt
index 77a864ed2bf3..76bad015d2d5 100644
--- a/board/qemu/ppc-e500mc/readme.txt
+++ b/board/qemu/ppc-e500mc/readme.txt
@@ -1,5 +1,5 @@
 Run the emulation with:
 
- qemu-system-ppc -M ppce500 -cpu e500mc -m 256 -kernel output/images/uImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic # qemu_ppc_e500mc_defconfig
+ qemu-system-ppc -M ppce500 -cpu e500mc -m 256 -kernel output/images/uImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -net nic,model=virtio-net-pci -net user -append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic # qemu_ppc_e500mc_defconfig
 
 The login prompt will appear in the terminal that started Qemu.
diff --git a/configs/qemu_ppc_e500mc_defconfig b/configs/qemu_ppc_e500mc_defconfig
index 1a5b1e3c2c83..232bc1f70c69 100644
--- a/configs/qemu_ppc_e500mc_defconfig
+++ b/configs/qemu_ppc_e500mc_defconfig
@@ -2,7 +2,8 @@
 BR2_powerpc=y
 BR2_powerpc_e500mc=y
 
-# Serial port config
+# System
+BR2_SYSTEM_DHCP="eth0"
 BR2_TARGET_GENERIC_GETTY_PORT="ttyS0"
 
 # Image
-- 
2.31.1

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Re: [Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Thomas Petazzoni]

Hello Cédric,

On Fri, 12 Nov 2021 17:04:11 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> PowerNV (as Non-Virtualized) is the "baremetal" platform using the
> OPAL [1] firmware. It runs Linux on IBM and OpenPOWER systems and can
> be used as an hypervisor OS, running KVM guests, or simply as a host
> OS. OPAL includes a Linux kernel and a buildroot rootfs which acts as
> a bootloader [2] for the various systems installed on disks.

For the person not familiar with all this OpenPOWER stuff, it's very
complex to understand all these firmware, virtualized stuff,
hypervisor, etc.

> diff --git a/board/qemu/ppc64le-powernv/readme.txt b/board/qemu/ppc64le-powernv/readme.txt
> new file mode 100644
> index 000000000000..ee102a3d6846
> --- /dev/null
> +++ b/board/qemu/ppc64le-powernv/readme.txt
> @@ -0,0 +1,5 @@
> +Run the emulation with:
> +
> +qemu-system-ppc64 -M powernv9 -kernel vmlinux -append "console=hvc0 rootwait root=/dev/nvme0n1" -device nvme,bus=pcie.3,addr=0x0,drive=drive0,serial=1234 -drive file=./rootfs.ext2,if=none,id=drive0,format=raw,cache=none -device e1000e,netdev=net0,mac=C0:FF:EE:00:01:03,bus=pcie.1,addr=0x0  -netdev user,id=net0 -serial mon:stdio -nographic # qemu_ppc64le_powernv_defconfig

You're emulating a powernv9, so we assume based on the Power9 processor.

> @@ -0,0 +1,29 @@
> +# Architecture
> +BR2_powerpc64le=y
> +BR2_powerpc_power8=y

But you're targeting Power8.

Could you clarify?

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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Re: [Buildroot] [PATCH 2/3] configs/qemu_ppc64_e5500: Enable dhcp on network interface

[Thomas Petazzoni]

On Fri, 12 Nov 2021 17:04:12 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> Add a virtio-net-pci device with a user mode host network backend
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  board/qemu/ppc64-e5500/readme.txt  | 2 +-
>  configs/qemu_ppc64_e5500_defconfig | 3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)

Applied to master, thanks.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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Re: [Buildroot] [PATCH 3/3] configs/qemu_ppc_e500mc: Enable dhcp on network interface

[Thomas Petazzoni]

On Fri, 12 Nov 2021 17:04:13 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> Add a virtio-net-pci device with a user mode host network backend
> 
> Cc: Bin Meng <bmeng.cn@gmail.com>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  board/qemu/ppc-e500mc/readme.txt  | 2 +-
>  configs/qemu_ppc_e500mc_defconfig | 3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)

Applied to master, thanks.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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Re: [Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Cédric Le Goater]

Hello Thomas,

On 12/28/21 22:14, Thomas Petazzoni wrote:
> Hello Cédric,
> 
> On Fri, 12 Nov 2021 17:04:11 +0100
> Cédric Le Goater <clg@kaod.org> wrote:
> 
>> PowerNV (as Non-Virtualized) is the "baremetal" platform using the
>> OPAL [1] firmware. It runs Linux on IBM and OpenPOWER systems and can
>> be used as an hypervisor OS, running KVM guests, or simply as a host
>> OS. OPAL includes a Linux kernel and a buildroot rootfs which acts as
>> a bootloader [2] for the various systems installed on disks.
> 
> For the person not familiar with all this OpenPOWER stuff, it's very
> complex to understand all these firmware, virtualized stuff,
> hypervisor, etc.

Let's try differently,

On these systems, the FW is comparable to U-Boot as it loads kernel and
initramfs images from flash. The initramfs is a buildroot environment
which includes the petitboot [*] boot loader. This second boot loader
does the device discovery and kexecs a new Linux image from disk or
network.

What we care about here is only the first level which uses the buildroot
image. petitboot is another topic.

As for QEMU, it implements 3 machines POWER8, POWER9 and Power10
processors that we use for dev and tests. I have chosen in the QEMU
script to boot directly from a nvme disk because it is simple enough
but using a ramfs would be closer to reality.

The hypervisor part is simply a feature of this Linux PPC platform,
that is called PowerNV.

[*] https://github.com/open-power/petitboot/

>> diff --git a/board/qemu/ppc64le-powernv/readme.txt b/board/qemu/ppc64le-powernv/readme.txt
>> new file mode 100644
>> index 000000000000..ee102a3d6846
>> --- /dev/null
>> +++ b/board/qemu/ppc64le-powernv/readme.txt
>> @@ -0,0 +1,5 @@
>> +Run the emulation with:
>> +
>> +qemu-system-ppc64 -M powernv9 -kernel vmlinux -append "console=hvc0 rootwait root=/dev/nvme0n1" -device nvme,bus=pcie.3,addr=0x0,drive=drive0,serial=1234 -drive file=./rootfs.ext2,if=none,id=drive0,format=raw,cache=none -device e1000e,netdev=net0,mac=C0:FF:EE:00:01:03,bus=pcie.1,addr=0x0  -netdev user,id=net0 -serial mon:stdio -nographic # qemu_ppc64le_powernv_defconfig
> 
> You're emulating a powernv9, so we assume based on the Power9 processor.
> 
>> @@ -0,0 +1,29 @@
>> +# Architecture
>> +BR2_powerpc64le=y
>> +BR2_powerpc_power8=y
> 
> But you're targeting Power8.

yes  
> Could you clarify?

because the same image can be used for the QEMU machine implementing
the POWER8 processor, which also works for POWER9 and Power10.
Thanks,

C.
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Re: [Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Thomas Petazzoni]

Hello Cédric,

On Tue, 28 Dec 2021 23:50:29 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> Let's try differently,
> 
> On these systems, the FW is comparable to U-Boot as it loads kernel and
> initramfs images from flash. The initramfs is a buildroot environment
> which includes the petitboot [*] boot loader. This second boot loader
> does the device discovery and kexecs a new Linux image from disk or
> network.
> 
> What we care about here is only the first level which uses the buildroot
> image. petitboot is another topic.
> 
> As for QEMU, it implements 3 machines POWER8, POWER9 and Power10
> processors that we use for dev and tests. I have chosen in the QEMU
> script to boot directly from a nvme disk because it is simple enough
> but using a ramfs would be closer to reality.
> 
> The hypervisor part is simply a feature of this Linux PPC platform,
> that is called PowerNV.
> 
> [*] https://github.com/open-power/petitboot/

Thanks for the additional explanations!

> > Could you clarify?  
> 
> because the same image can be used for the QEMU machine implementing
> the POWER8 processor, which also works for POWER9 and Power10.

So why don't we test it with -M powernv8 ?

Best regards,

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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Re: [Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Cédric Le Goater]

Hello Thomas,

>> because the same image can be used for the QEMU machine implementing
>> the POWER8 processor, which also works for POWER9 and Power10.
> 
> So why don't we test it with -M powernv8 ?

Sure. Would you rather have a ppc64le-powernv8 and a ppc64le-powernv9
config instead ?

I have a few other patches adding similar boards for 44x CPUs. I can
resend a v2 for the whole.

What's the process to bump the QEMU version ?

Thanks,

C.

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Re: [Buildroot] [PATCH 1/3] configs/qemu: Add a ppc64le-powernv configuration

[Thomas Petazzoni]

Hello Cédric,

On Wed, 29 Dec 2021 15:01:30 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> >> because the same image can be used for the QEMU machine implementing
> >> the POWER8 processor, which also works for POWER9 and Power10.  
> > 
> > So why don't we test it with -M powernv8 ?  
> 
> Sure. Would you rather have a ppc64le-powernv8 and a ppc64le-powernv9
> config instead ?

In the interest of not growing too much the number of defconfigs, I
would perhaps suggest to have just a powernv8 configuration, and in its
readme.txt file, indicate that it can be similarly used on powerpcnv9.

> I have a few other patches adding similar boards for 44x CPUs. I can
> resend a v2 for the whole.

Sounds useful.

> What's the process to bump the QEMU version ?

Send a patch against the package/qemu/ package, it's as simple as that.
Ideally, when you do that, make sure to retest all the Qemu defconfigs,
to ensure they continue to boot well under the new Qemu version. You
can use Gitlab CI to automate this testing.

Best regards,

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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