Re: [PATCH 0/4] Xen: Add Q35 initial support for HVM guests

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Fri, Mar 13, 2026 at 04:46:56PM +0000, Thierry Escande wrote:
> This patch series introduces Q35 chipset support for Xen HVM guests. This is
> based on the work from Alexey Gerasimenko (See patchset [1] for reference).
> 
> This series does not implement device passthrough as this will need more work
> on the Xen side to support multiple PCI buses. Since Q35 chipset does not
> support device hotplugging and with current Xen mechanism for device
> passthrough, they have to be plugged to a new PCIe root port, i.e. not the PCI
> bus 0.
> 
> As a first step for Q35 guests support, this series implements:
> - Legacy interrupt routing for the ICH9 LPC bridge (i.e. not IOAPIC)
> - Xen HVM machine initialization in pc_q35_init()
> - Access to PCIe Extended Config Space
> - Fix for incorrect values and usage for PCIEXBAR masks

Xen maintainers, who's merging this?

> The corresponding patchset for the Xen Project has been posted at [2].
> 
> [1] https://lore.kernel.org/xen-devel/cover.1520867740.git.x1917x@xxxxxxxxx/
> [2] 
> https://lore.kernel.org/xen-devel/20260313163455.790692-1-thierry.escande@xxxxxxxxxx/
> 
> Alexey Gerasimenko (2):
>   pc/xen: Xen Q35 support: provide IRQ handling for PCI devices
>   q35: Fix incorrect values for PCIEXBAR masks
> 
> Thierry Escande (2):
>   q35/xen: Add Xen support for Q35
>   xen: Handle PCIe config space size in cpu_ioreq_config()
> 
>  hw/i386/pc_piix.c         |  2 --
>  hw/i386/pc_q35.c          | 12 +++++++++++-
>  hw/i386/xen/xen-hvm.c     | 38 ++++++++++++++++++++++++++++++++++++++
>  hw/isa/lpc_ich9.c         | 16 +++++++++++++---
>  hw/pci-host/q35.c         |  6 +++---
>  hw/xen/xen-hvm-common.c   | 11 +++++++----
>  include/hw/pci-host/q35.h |  4 ++--
>  include/hw/xen/xen.h      |  5 +++++
>  stubs/xen-hw-stub.c       |  4 ++++
>  9 files changed, 83 insertions(+), 15 deletions(-)
> 
> -- 
> 2.51.0
> 
> 
> 
> --
> Thierry Escande | Vates XCP-ng Developer
> 
> XCP-ng & Xen Orchestra - Vates solutions
> 
> web: https://vates.tech