Re: [PATCH v4 0/9] x86/hvm: Add Extended MSI destination ID support

[Julian Vetter <julian.vetter@xxxxxxxxxx>]

Thank you Teddy for your feedback on the patchset. Jan and Roger do you 
have any additional remarks on the patchset? Is the new structure what 
you had in mind Roger?

Thank you.

Julian

On 4/27/26 15:54, Julian Vetter wrote:
> Thank you very much Roger and Jan for your feedback! I have addressed
> your feedback, see below. For me there is only one question, I'm not
> sure if this is what you had in mind Roger when you wrote:
> "Retrofitting the new interface into the old one seems weird.  I would
> do it the other way around - implement the old bind domctl on top of
> an interface that's more suited for the new DM op."
> It requires some preparatory work. But I tried to make the
> restructunring diffs as easy to review as possible by splitting the
> refactoring into mutliple steps.
> 
> Signed-off-by: Julian Vetter <julian.vetter@xxxxxxxxxx>
> ---
> Changes in v4:
> - Replaced the v3 approach of extending the XEN_DOMCTL_bind_pt_irq
>    gflags ABI (XEN_DOMCTL_VMSI_X86_EXT_DEST_ID_MASK / VMSI_X86_FULL_DEST)
>    with raw MSI addr + data storage throughout. pt_irq_bind_msi() now
>    accepts the raw address + data values and decodes the destination
>    internally. No public domctl ABI changes
> - As suggested by Roger, replaced XEN_DMOP_enable_ext_dest_id (v3 patch
>    6, a separate call before domain start) with a flags byte from the
>    existing pad[3] field of XEN_DMOP_create_ioreq_server. The new
>    XEN_DMOP_IOREQ_SERVER_EXT_DEST_ID flag lets each server signal support
>    at registration time and allows the feature to be levelled across all
>    servers before arch_domain_creation_finished()
> - Redirect xc_domain_{update,unbind}_msi_irq() in libxenctrl to use the
>    new DM ops, and reject PT_IRQ_TYPE_MSI in
>    XEN_DOMCTL_{bind,unbind}_pt_irq (as suggested by Jan)
> - Add three preparatory no-functional-change commits (patches 2-4) that
>    wrap the restart block in braces, extract pt_irq_dpci_setup(), and
>    extract the PT_IRQ_TYPE_MSI case body into pt_irq_bind_msi(), making
>    the interface change in patch 5 reviewable as a clean diff
> - Rework ioapic_check() to validate named fields (base_address, APIC ID
>    width, ioregsel range) instead of rejecting any non-zero reserved
>    bits, which would have falsely rejected RTEs carrying extended
>    destination IDs
> ---
> Julian Vetter (9):
>    x86/vioapic: Add ioapic_check() to validate IO-APIC state before
>      restore
>    x86/passthrough: Wrap pt_irq_create_bind() restart block in braces
>    x86/passthrough: Extract pt_irq_dpci_setup() from pt_irq_create_bind()
>    x86/passthrough: Extract PT_IRQ_TYPE_MSI body into pt_irq_bind_msi()
>    x86/passthrough: Introduce pt_irq_bind_msi() as canonical MSI bind
>      path
>    x86/hvm: Support extended destination IDs in virtual MSI and IO-APIC
>    x86/dmop: Add XEN_DMOP_{bind,unbind}_pt_msi_irq DM ops
>    hvm/ioreq: Negotiate extended destination ID support per ioreq server
>    x86/cpuid: Advertise XEN_HVM_CPUID_EXT_DEST_ID when device model opts
>      in
> 
>   tools/include/xendevicemodel.h          |  34 +-
>   tools/libs/ctrl/xc_devicemodel_compat.c |   2 +-
>   tools/libs/ctrl/xc_domain.c             |  52 ++--
>   tools/libs/devicemodel/core.c           |  41 ++-
>   xen/arch/arm/ioreq.c                    |   5 +
>   xen/arch/x86/cpuid.c                    |  13 +
>   xen/arch/x86/domain.c                   |  10 +
>   xen/arch/x86/domctl.c                   |  10 +-
>   xen/arch/x86/hvm/dm.c                   |  68 ++++
>   xen/arch/x86/hvm/ioreq.c                |  37 +++
>   xen/arch/x86/hvm/irq.c                  |   9 +-
>   xen/arch/x86/hvm/vioapic.c              |  50 ++-
>   xen/arch/x86/hvm/vmsi.c                 |  54 +---
>   xen/arch/x86/include/asm/hvm/domain.h   |   9 +
>   xen/arch/x86/include/asm/hvm/hvm.h      |   4 +-
>   xen/arch/x86/include/asm/hvm/irq.h      |   4 +-
>   xen/arch/x86/include/asm/hvm/vioapic.h  |  12 +
>   xen/arch/x86/include/asm/msi.h          |  18 +-
>   xen/common/ioreq.c                      |  13 +-
>   xen/drivers/passthrough/x86/hvm.c       | 396 ++++++++++++++----------
>   xen/include/public/arch-x86/hvm/save.h  |  21 +-
>   xen/include/public/hvm/dm_op.h          |  53 +++-
>   xen/include/xen/iommu.h                 |   3 +
>   xen/include/xen/ioreq.h                 |  27 ++
>   xen/include/xlat.lst                    |   2 +
>   25 files changed, 703 insertions(+), 244 deletions(-)
> 



--
Julian Vetter | Vates Hypervisor & Kernel Developer

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