Add basic riscv64 architecture support

[vhaudiquet]

This adds basic riscv64 architecture support.
It allows building the snap on riscv64, and then running basic commands:

ubuntu@p550:~$ lscompute
{
  "cpus": [
    {
      "architecture": "riscv64",
      "isa": [
        "rv64imafdch",
        "zicsr",
        "zifencei",
        "zba",
        "zbb",
        "sscofpmf"
      ]
    }
  ],
  "memory": {
    "total-ram": 16743100416,
    "total-swap": 0
  },
  "disk": {
    "/var/lib/snapd/snaps": {
      "total": 125930070016,
      "avail": 14488858624
    }
  },
  "devices": [
    {
      "bus": "pci",
      "slot": "0000:00:00.0",
      "bus-number": "0x0",
      "device-class": "0x604",
      "vendor-id": "0x1FE1",
      "device-id": "0x2030",
      "subvendor-id": "0x0",
      "subdevice-id": "0x0",
      "vendor-name": "Beijing ESWIN Computing Technology Co., Ltd.",
      "device-name": "EIC7700 Root Complex"
    },
    {
      "bus": "usb",
      "bus-number": 3,
      "device-number": 2,
      "vendor-id": "0x5E3",
      "product-id": "0x610",
      "vendor-name": "Genesys Logic, Inc.",
      "product-name": "Hub"
    },
    {
      "bus": "usb",
      "bus-number": 4,
      "device-number": 2,
      "vendor-id": "0x5E3",
      "product-id": "0x620",
      "vendor-name": "Genesys Logic, Inc.",
      "product-name": "GL3523 Hub"
    },
    {
      "bus": "usb",
      "bus-number": 1,
      "device-number": 1,
      "vendor-id": "0x1D6B",
      "product-id": "0x2",
      "vendor-name": "Linux Foundation",
      "product-name": "2.0 root hub"
    },
    {
      "bus": "usb",
      "bus-number": 2,
      "device-number": 1,
      "vendor-id": "0x1D6B",
      "product-id": "0x3",
      "vendor-name": "Linux Foundation",
      "product-name": "3.0 root hub"
    },
    {
      "bus": "usb",
      "bus-number": 3,
      "device-number": 1,
      "vendor-id": "0x1D6B",
      "product-id": "0x2",
      "vendor-name": "Linux Foundation",
      "product-name": "2.0 root hub"
    },
    {
      "bus": "usb",
      "bus-number": 4,
      "device-number": 1,
      "vendor-id": "0x1D6B",
      "product-id": "0x3",
      "vendor-name": "Linux Foundation",
      "product-name": "3.0 root hub"
    }
  ]
}

See also Original PR to inference-snaps-cli

[Copilot]

Pull request overview

Adds baseline riscv64 support to lscompute’s CPU detection and Snap packaging, plus a new SiFive P550 Premier machine fixture to exercise the end-to-end pipeline on riscv64.

Changes:

• Extend CPU parsing/model to include a riscv64 isa field sourced from /proc/cpuinfo.
• Update Snap build logic so nvidia-smi is only pulled/used on supported architectures and provides a stub elsewhere.
• Add a new test_data/machines/sifive-p550-premier fixture and tests covering riscv64 dispatch + full Info() pipeline.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test_data/machines/sifive-p550-premier/machine-root/sys/bus/pci/devices/0000:00:00.0/vendor	Adds PCI vendor ID fixture data for the P550 machine.
test_data/machines/sifive-p550-premier/machine-root/sys/bus/pci/devices/0000:00:00.0/subsystem_vendor	Adds PCI subsystem vendor fixture data for the P550 machine.
test_data/machines/sifive-p550-premier/machine-root/sys/bus/pci/devices/0000:00:00.0/subsystem_device	Adds PCI subsystem device fixture data for the P550 machine.
test_data/machines/sifive-p550-premier/machine-root/sys/bus/pci/devices/0000:00:00.0/device	Adds PCI device ID fixture data for the P550 machine.
test_data/machines/sifive-p550-premier/machine-root/sys/bus/pci/devices/0000:00:00.0/class	Adds PCI class fixture data for the P550 machine.
test_data/machines/sifive-p550-premier/machine-root/run/disk-stats.json	Adds disk stats fixture data for end-to-end machine parsing.
test_data/machines/sifive-p550-premier/machine-root/proc/sys/kernel/arch	Adds riscv64 arch fixture input for architecture detection.
test_data/machines/sifive-p550-premier/machine-root/proc/meminfo	Adds meminfo fixture input for memory parsing.
test_data/machines/sifive-p550-premier/machine-root/proc/cpuinfo	Adds riscv64 cpuinfo fixture input for CPU parsing.
snap/snapcraft.yaml	Makes nvidia-smi packaging arch-aware and provides a stub on unsupported arches.
pkg/machine/cpu/types.go	Adds isa field to CPU output model and internal proc structure for riscv64.
pkg/machine/cpu/proc_cpuinfo.go	Adds riscv64 /proc/cpuinfo parsing and dispatcher routing.
pkg/machine/cpu/proc_cpuinfo_test.go	Adds riscv64 cpuinfo fixture and dispatcher test coverage.
pkg/machine/cpu/cpu.go	Maps parsed riscv64 ISA into the exported CpuInfo.
pkg/machine/cpu/cpu_test.go	Adds riscv64 end-to-end fixture test coverage for Info() and infoFromRawData().

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[jpm-canonical]

I do not have access to a riscv machine, nor can I get access to one on testflinger.

I did a code review, and I am happy with these changes.

I also added another riscv64 machine to the test_data. We had this test set from before but never added it here because riscv was not supported. This machine also passes the tests.