Re: [PATCH v3 0/4] virtio-iommu: Support VIRTIO_IOMMU_F_BYPASS_CONFIG

[Eric Auger]

Hi Jean,

On 2/14/22 1:43 PM, Jean-Philippe Brucker wrote:
> Replace the VIRTIO_IOMMU_F_BYPASS feature with
> VIRTIO_IOMMU_F_BYPASS_CONFIG, which enables a config space bit to switch
> global bypass on and off.
>
> Add a boot-bypass option, which defaults to 'on' to be in line with
> other vIOMMUs and to allow running firmware/bootloader that are unaware
> of the IOMMU. x86 doesn't need a workaround to boot with virtio-iommu
> anymore.
>
> Since v2 [1]:
> * Added the new bypass bits to the migration stream.
>   As discussed on the v2 thread, we assume that cross-version
>   compatibility is not required for live migration at the moment, so we
>   only increase the version number. Patch 2 says: "We add the bypass
>   field to the migration stream without introducing subsections, based
>   on the assumption that this virtio-iommu device isn't being used in
>   production enough to require cross-version migration at the moment
>   (all previous version required workarounds since they didn't support
>   ACPI and boot-bypass)."
>
> [1] 
> https://lore.kernel.org/qemu-devel/20220127142940.671333-1-jean-philippe@linaro.org/
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>

I tested both the boot bypass feature with virtio-blk-pci,
virtio-net-pci and virtio-gpu-pci and migration.

Thanks

Eric

>
> Jean-Philippe Brucker (4):
>   linux-headers: update to v5.17-rc1
>   virtio-iommu: Default to bypass during boot
>   virtio-iommu: Support bypass domain
>   tests/qtest/virtio-iommu-test: Check bypass config
>
>  include/hw/virtio/virtio-iommu.h              |   1 +
>  include/standard-headers/asm-x86/kvm_para.h   |   1 +
>  include/standard-headers/drm/drm_fourcc.h     |  11 ++
>  include/standard-headers/linux/ethtool.h      |   1 +
>  include/standard-headers/linux/fuse.h         |  60 +++++++-
>  include/standard-headers/linux/pci_regs.h     | 142 +++++++++---------
>  include/standard-headers/linux/virtio_gpio.h  |  72 +++++++++
>  include/standard-headers/linux/virtio_i2c.h   |  47 ++++++
>  include/standard-headers/linux/virtio_iommu.h |   8 +-
>  .../standard-headers/linux/virtio_pcidev.h    |  65 ++++++++
>  include/standard-headers/linux/virtio_scmi.h  |  24 +++
>  linux-headers/asm-generic/unistd.h            |   5 +-
>  linux-headers/asm-mips/unistd_n32.h           |   2 +
>  linux-headers/asm-mips/unistd_n64.h           |   2 +
>  linux-headers/asm-mips/unistd_o32.h           |   2 +
>  linux-headers/asm-powerpc/unistd_32.h         |   2 +
>  linux-headers/asm-powerpc/unistd_64.h         |   2 +
>  linux-headers/asm-riscv/bitsperlong.h         |  14 ++
>  linux-headers/asm-riscv/mman.h                |   1 +
>  linux-headers/asm-riscv/unistd.h              |  44 ++++++
>  linux-headers/asm-s390/unistd_32.h            |   2 +
>  linux-headers/asm-s390/unistd_64.h            |   2 +
>  linux-headers/asm-x86/kvm.h                   |  16 +-
>  linux-headers/asm-x86/unistd_32.h             |   1 +
>  linux-headers/asm-x86/unistd_64.h             |   1 +
>  linux-headers/asm-x86/unistd_x32.h            |   1 +
>  linux-headers/linux/kvm.h                     |  17 +++
>  hw/virtio/virtio-iommu.c                      |  99 ++++++++++--
>  tests/qtest/virtio-iommu-test.c               |   2 +
>  hw/virtio/trace-events                        |   4 +-
>  30 files changed, 561 insertions(+), 90 deletions(-)
>  create mode 100644 include/standard-headers/linux/virtio_gpio.h
>  create mode 100644 include/standard-headers/linux/virtio_i2c.h
>  create mode 100644 include/standard-headers/linux/virtio_pcidev.h
>  create mode 100644 include/standard-headers/linux/virtio_scmi.h
>  create mode 100644 linux-headers/asm-riscv/bitsperlong.h
>  create mode 100644 linux-headers/asm-riscv/mman.h
>  create mode 100644 linux-headers/asm-riscv/unistd.h
>