Re: [PATCH 00/14] hw/vfio: Build various objects once

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 8/3/25 18:48, Cédric Le Goater wrote:
> Hello,
> 
> On 3/7/25 19:03, Philippe Mathieu-Daudé wrote:
>> By doing the following changes:
>> - Clean some headers up
>> - Replace compile-time CONFIG_KVM check by kvm_enabled()
>> - Replace compile-time CONFIG_IOMMUFD check by iommufd_builtin()
>> we can build less vfio objects.
>>
>> Philippe Mathieu-Daudé (14):
>>    hw/vfio/common: Include missing 'system/tcg.h' header
>>    hw/vfio/spapr: Do not include <linux/kvm.h>
>>    hw/vfio: Compile some common objects once
>>    hw/vfio: Compile more objects once
>>    hw/vfio: Compile iommufd.c once
>>    system: Declare qemu_[min/max]rampagesize() in 'system/hostmem.h'
>>    hw/vfio: Compile display.c once
>>    system/kvm: Expose kvm_irqchip_[add,remove]_change_notifier()
>>    hw/vfio/pci: Convert CONFIG_KVM check to runtime one
>>    system/iommufd: Introduce iommufd_builtin() helper
>>    hw/vfio/pci: Check CONFIG_IOMMUFD at runtime using iommufd_builtin()
>>    hw/vfio/ap: Check CONFIG_IOMMUFD at runtime using iommufd_builtin()
>>    hw/vfio/ccw: Check CONFIG_IOMMUFD at runtime using iommufd_builtin()
>>    hw/vfio/platform: Check CONFIG_IOMMUFD at runtime using
>>      iommufd_builtin
>>
>>   docs/devel/vfio-iommufd.rst  |  2 +-
>>   include/exec/ram_addr.h      |  3 --
>>   include/system/hostmem.h     |  3 ++
>>   include/system/iommufd.h     |  8 +++++
>>   include/system/kvm.h         |  8 ++---
>>   target/s390x/kvm/kvm_s390x.h |  2 +-
>>   accel/stubs/kvm-stub.c       | 12 ++++++++
>>   hw/ppc/spapr_caps.c          |  1 +
>>   hw/s390x/s390-virtio-ccw.c   |  1 +
>>   hw/vfio/ap.c                 | 27 ++++++++---------
>>   hw/vfio/ccw.c                | 27 ++++++++---------
>>   hw/vfio/common.c             |  1 +
>>   hw/vfio/iommufd.c            |  1 -
>>   hw/vfio/migration.c          |  1 -
>>   hw/vfio/pci.c                | 57 +++++++++++++++++-------------------
>>   hw/vfio/platform.c           | 25 ++++++++--------
>>   hw/vfio/spapr.c              |  4 +--
>>   hw/vfio/meson.build          | 33 ++++++++++++---------
>>   18 files changed, 117 insertions(+), 99 deletions(-)
>>
> 
> Patches 1-9 look ok and should be considered for the next PR if
> maintainers ack patch 6 and 8.

OK.

> vfio-amd-xgbe and vfio-calxeda-xgmac should be treated like
> vfio-platform, and since vfio-platform was designed for aarch64,
> these devices should not be available on arm, ppc, ppc64, riscv*,
> loongarch. That said, vfio-platform and devices being deprecated in
> the QEMU 10.0 cycle, we could just wait for the removal in QEMU 10.2.
> 
> How could we (simply) remove CONFIG_VFIO_IGD in hw/vfio/pci-quirks.c ?
> and compile this file only once.
> 
> The vfio-pci devices are available in nearly all targets when it
> only makes sense to have them in i386, x86_64, aarch64, ppc64,
> where they are supported, and also possibly in ppc (tcg) and arm
> (tcg) for historical reasons and just because they happen to work.
> ppc (tcg) doesn't support MSIs with vfio-pci devices so I don't
> think we care much.
> 
> Patches 10-14 are wrong because they remove the "iommufd" property of
> the "vfio-*" devices. We can't take these.

I suppose this is due to the wrong implementation of iommufd_builtin()
I mentioned in patch #10, which check instance but not class.

Thanks!