Re: [PATCH 0/3] hw/i386/microvm: add uefi-vars-sysbus support via platform bus

On Wed, Jul 01, 2026 at 04:16:16PM +0200, Luigi Leonardi wrote:
>This series adds support for the uefi-vars-sysbus device on the microvm
>machine type, enabling persistent UEFI variable storage.
>
>The uefi-vars-sysbus device is a sysbus device that is attached to the
>platform bus, which microvm does not currently support. To address this,
>the series adds a platform bus to microvm, following the same
>pattern used by the ARM virt machine.
>
>The platform bus is mapped at 0xfec20000 with a 1 MB window, placed
>after the IOAPICs. It is created without IRQ lines since the
>uefi-vars-sysbus device only requires MMIO.
>
>Patch 1 fixes a crash in the platform bus core when num_irqs is zero,
>        which is needed to support an MMIO-only platform bus.
>Patch 2 adds the platform bus to microvm with MMIO mapping and FDT
>        integration.
>Patch 3 allows the uefi-vars-sysbus device to be instantiated on
>        microvm.
>
>Corresponding edk2 changes[1]
>
>[1]https://github.com/tianocore/edk2/pull/12751
>
>To: [email protected]
>Cc: Paolo Bonzini <[email protected]>
>Cc: Michael S. Tsirkin <[email protected]>
>Cc: Richard Henderson <[email protected]>
>Cc: Sergio Lopez <[email protected]>
>Cc: Gerd Hoffmann <[email protected]>
>
>Suggested-by: Gerd Hoffmann <[email protected]>
>Signed-off-by: Luigi Leonardi <[email protected]>
>---
>Luigi Leonardi (3):
>      hw/core/platform-bus: fix crash when num_irqs is zero
>      hw/i386/microvm: add platform bus support
>      hw/i386/microvm: add uefi-vars-sysbus support
>
> hw/core/platform-bus.c    |  4 ++++
> hw/i386/Kconfig           |  1 +
> hw/i386/microvm-dt.c      |  9 +++++++++
> hw/i386/microvm.c         | 38 ++++++++++++++++++++++++++++++++++++++
> include/hw/i386/microvm.h |  4 ++++
> 5 files changed, 56 insertions(+)
>---
>base-commit: f38d6ae70f100fc8d3f095a842d2f1ca29262218
>change-id: 20260701-microvm_uefi_var-8a434ce7f8b9
>
>Best regards,
>-- 
>Luigi Leonardi <[email protected]>
>
>

Gentle ping :)

Thanks,
Luigi