Re: [PATCH 0/5] Add new headers for Hyper-V Dom0

Nuno Das Neves
2024-10-23T00:51:07Z

On 10/10/2024 11:21 AM, Michael Kelley wrote:
> From: Nuno Das Neves <nunodasneves@linux.microsoft.com> Sent: Thursday, October 3, 2024 12:51 PM
>>>> An intermediary header "hv_defs.h" is introduced to conditionally
>> include either hyperv-tlfs.h or hvhdk.h. This is required because
>> several headers which today include hyperv-tlfs.h, are shared
>> between Hyper-V and KVM code (e.g. mshyperv.h).
>
> Have you considered user space code that uses
> include/linux/hyperv.h? Which of the two schemes will it use? That code
> needs to compile correctly on x86 and ARM64 after your changes.
> User space code includes the separate DPDK project, and some of the
> tools in the kernel tree under tools/hv. Anything that uses the
> uio_hv_generic.c driver falls into this category.
>
Unless I misunderstand something, the uapi code isn't affected at all
by this patch set. e.g. the code in tools/hv uses include/uapi/linux/hyperv.h,
which doesn't include any other Hyper-V headers.

I'm not aware of how the DPDK project uses the Hyper-V definitions, but if it
is getting headers from uapi it should also be unaffected.

> I think there's also user space code that is built for vDSO that might pull
> in the .h files you are modifying. There are in-progress patches dealing
> with vDSO include files, such as [1]. My general comment on vDSO
> is to be careful in making #include file changes that it uses, but I'm
> not knowledgeable enough on how vDSO is built to give specific
> guidance. :-(
>
Hmm, interesting, looks like it does get used by userspace. The tsc page
is mapped into userspace in vdso.vma.c, and read in vdso/gettimeofday.h.

That is unexpected for me, since these things aren't in uapi. However I don't
anticipate a problem. The definitions used haven't changed, just the headers
they are included from.

Thanks
Nuno

> Michael
>
> [1] https://lore.kernel.org/lkml/20241010135146.181175-1-vincenzo.frascino@arm.com/
>
>>
>> Summary:
>> Patch 1-2: Cleanup patches
>> Patch 3: Add the new headers (hvhdk.h, etc..) in include/hyperv/
>> Patch 4: Add hv_defs.h and use it in mshyperv.h, svm.h,
>> hyperv_timer.h
>> Patch 5: Switch to the new headers, only in Hyper-V code
>>
>> Nuno Das Neves (5):
>> hyperv: Move hv_connection_id to hyperv-tlfs.h
>> hyperv: Remove unnecessary #includes
>> hyperv: Add new Hyper-V headers
>> hyperv: Add hv_defs.h to conditionally include hyperv-tlfs.h or
>> hvhdk.h
>> hyperv: Use hvhdk.h instead of hyperv-tlfs.h in Hyper-V code
>>
>> arch/arm64/hyperv/hv_core.c | 3 +-
>> arch/arm64/hyperv/mshyperv.c | 1 +
>> arch/arm64/include/asm/mshyperv.h | 2 +-
>> arch/x86/entry/vdso/vma.c | 1 +
>> arch/x86/hyperv/hv_apic.c | 2 +-
>> arch/x86/hyperv/hv_init.c | 3 +-
>> arch/x86/hyperv/hv_proc.c | 4 +-
>> arch/x86/hyperv/hv_spinlock.c | 1 +
>> arch/x86/hyperv/hv_vtl.c | 1 +
>> arch/x86/hyperv/irqdomain.c | 1 +
>> arch/x86/hyperv/ivm.c | 2 +-
>> arch/x86/hyperv/mmu.c | 2 +-
>> arch/x86/hyperv/nested.c | 2 +-
>> arch/x86/include/asm/kvm_host.h | 1 -
>> arch/x86/include/asm/mshyperv.h | 3 +-
>> arch/x86/include/asm/svm.h | 2 +-
>> arch/x86/include/asm/vdso/gettimeofday.h | 1 +
>> arch/x86/kernel/cpu/mshyperv.c | 2 +-
>> arch/x86/kernel/cpu/mtrr/generic.c | 1 +
>> arch/x86/kvm/vmx/vmx_onhyperv.h | 1 -
>> arch/x86/mm/pat/set_memory.c | 2 -
>> drivers/clocksource/hyperv_timer.c | 2 +-
>> drivers/hv/channel.c | 1 +
>> drivers/hv/channel_mgmt.c | 1 +
>> drivers/hv/connection.c | 1 +
>> drivers/hv/hv.c | 1 +
>> drivers/hv/hv_balloon.c | 5 +-
>> drivers/hv/hv_common.c | 2 +-
>> drivers/hv/hv_kvp.c | 1 -
>> drivers/hv/hv_snapshot.c | 1 -
>> drivers/hv/hv_util.c | 1 +
>> drivers/hv/hyperv_vmbus.h | 1 -
>> drivers/hv/ring_buffer.c | 1 +
>> drivers/hv/vmbus_drv.c | 1 +
>> drivers/iommu/hyperv-iommu.c | 1 +
>> drivers/net/hyperv/netvsc.c | 1 +
>> drivers/pci/controller/pci-hyperv.c | 1 +
>> include/asm-generic/hyperv-tlfs.h | 9 +
>> include/asm-generic/mshyperv.h | 2 +-
>> include/clocksource/hyperv_timer.h | 2 +-
>> include/hyperv/hv_defs.h | 29 +
>> include/hyperv/hvgdk.h | 66 ++
>> include/hyperv/hvgdk_ext.h | 46 +
>> include/hyperv/hvgdk_mini.h | 1212 ++++++++++++++++++++++
>> include/hyperv/hvhdk.h | 733 +++++++++++++
>> include/hyperv/hvhdk_mini.h | 310 ++++++
>> include/linux/hyperv.h | 12 +-
>> net/vmw_vsock/hyperv_transport.c | 1 -
>> 48 files changed, 2442 insertions(+), 40 deletions(-)
>> create mode 100644 include/hyperv/hv_defs.h
>> create mode 100644 include/hyperv/hvgdk.h
>> create mode 100644 include/hyperv/hvgdk_ext.h
>> create mode 100644 include/hyperv/hvgdk_mini.h
>> create mode 100644 include/hyperv/hvhdk.h
>> create mode 100644 include/hyperv/hvhdk_mini.h
>>
>> --
>> 2.34.1
>>
>