Re: [PATCH 0/4] Nested virtualization fixes for root partition

Roman Kisel
2025-06-11T20:39:45Z

On 6/10/2025 4:52 PM, Nuno Das Neves wrote:
> Fixes for running as nested root partition on the Microsoft Hypervisor.
>
> The first patch prevents the vmbus driver being registered on baremetal, since
> there's no vmbus in this scenario.
>
> The second patch changes vmbus to make hypercalls to the L0 hypervisor instead
> of the L1. This is needed because L0 hypervisor, not the L1, is the one hosting
> the Windows root partition with the VMM that provides vmbus.
>
> The 3rd and 4th patches fix interrupt unmasking on nested. In this scenario,
> the L1 (nested) hypervisor does the interrupt mapping to root partition cores.
> The vectors just need to be mapped with MAP_DEVICE_INTERRUPT instead of
> affinitized with RETARGET_INTERRUPT.
>
> Mukesh Rathor (1):
> PCI: hv: Do not do vmbus initialization on baremetal
>
> Nuno Das Neves (1):
> Drivers: hv: Use nested hypercall for post message and signal event
>
> Stanislav Kinsburskii (2):
> x86: hyperv: Expose hv_map_msi_interrupt function
> PCI: hv: Use the correct hypercall for unmasking interrupts on nested
>
> arch/arm64/include/asm/mshyperv.h | 10 ++++++
> arch/x86/hyperv/irqdomain.c | 47 +++++++++++++++++++++--------
> arch/x86/include/asm/mshyperv.h | 2 ++
> drivers/hv/connection.c | 3 ++
> drivers/hv/hv.c | 3 ++
> drivers/pci/controller/pci-hyperv.c | 21 +++++++++++--
> 6 files changed, 71 insertions(+), 15 deletions(-)
>

Very cool stuff :) LGTM.

For the patch series:
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>

--
Thank you,
Roman