Re: Xen 4.21 Development Update [May]

["Roger Pau Monné" <roger.pau@citrix.com>]

On Mon, Jun 02, 2025 at 06:37:46PM +0200, Oleksii Kurochko wrote:
> Hello everyone,
> 
> This email only tracks big items for xen.git tree. Please reply for items
> you
> would like to see in 4.21 so that people have an idea what is going on and
> prioritise accordingly.
> 
> You're welcome to provide description and use cases of the feature you're
> working on.
> 
> = Timeline =
> 
> As there hasn't been any feedback on the proposed timeline shared here:
> https://lore.kernel.org/xen-devel/666e3f49-2f92-4828-8897-8579832bcaa2@gmail.com/T/#u
> 
> We can proceed with the suggested timeline as the release schedule for Xen
> 4.21.
> I've updated the Xen 4.21 Release Notes with this schedule, which can now be
> accessed via the RN link:
>   https://xenbits.xen.org/docs/unstable/support-matrix.html
> 
> = Updates =
> 
> The following items ( the links for them could be found int the list below )
> were moved to completed:
>   [since May 6 - Jun2]:
>     * Hypervisor:
>       - tools: remove qemu-traditional
>     * Arm:
>       - PCI devices passthrough on Arm, part 3
>     * x86:
>       - xen: cache control improvements
>   [since 4.20 relese - May 6]:
>     * Hypervisor:
>       - Move parts of Arm's Dom0less to common code
>       - remove libxenctrl usage from xenstored
>     * Arm:
>       - Enable early bootup of Armv8-R AArch32 systems
>     * x86:
>       - x86/HVM: emulation (MMIO) improvements
>     * RISC-V:
>       - RISC-V some preinit calls.
>       - Fixes for UBSAN & GCOV support for RISC-V.
> 
> Some new items added:
>  [since May]
>     * x86:
>      - Allow x86 to unflatten DTs
>      - hyperlaunch: move remaining pvh dom0 construction
>      - x86/hyperlaunch: introduce concept of core domains
>      - Confidential computing and AMD SEV support
>     * Arm:
>      - SMMU handling for PCIe Passthrough on ARM
>      - xen/arm: scmi: introduce SCI SCMI SMC multi-agent support
>      - Add initial Xen Suspend-to-RAM support on ARM64
>     * RISC-V:
>      - introduce p2m functionality
>  [since 4.20 release]
>     * Hypervisor:
>       - tools: remove qemu-traditional
>       - Physical address hypercall ABI ("HVMv2")
>       - xen: Untangle mm.h
>       - xen: introduce CONFIG_SYSCTL
>       - Add support for exact-node memory claims
>       - Several CI cleanups and improvements, plus yet another new runner
>     * x86:
>       - x86/EFI: prevent write-execute sections
>       - x86: Trenchboot Secure Launch DRTM (Xen)
>       - Hyperlaunch device tree for dom0 (v6)
>       - amd-cppc CPU Performance Scaling Driver (v4)
>       - Hyperlaunch domain builder
>       - kexec: add kexec support to Mini-OS
>       - xen: cache control improvements (should be moved to "Hypervisor"?)
>       - x86: generate xen.efi image with no write-execute sections
>       - x86/asm: cleanups after toolchain baseline upgrade
>     * Arm:
>       - Add support for R-Car Gen4 PCI host controller (v4)
>       - FF-A VM to VM support (v5)
>       - First chunk for Arm R82 and MPU support (v4)
>       - ARM split hardware and control domains (v5)
>       - MPU mm subsistem skeleton
>     * RISC-V:
>       - introduce basic UART support and interrupts for hypervisor mode
> 
> * Full list of items : *
> 
> = Projects =
> 
> == Hypervisor ==
> 
> * xen/console: cleanup console input switch logic (v1 -> v5)
>   - Denis Mukhin
>   -
> https://lore.kernel.org/xen-devel/20250530231841.73386-1-dmukhin@ford.com/
>   - https://patchew.org/Xen/20250530231841.73386-1-dmukhin@ford.com/
> 
> * xen: introduce CONFIG_SYSCTL (v3 -> v4)
>   -  Penny Zheng
>   - https://lore.kernel.org/xen-devel/20250528091708.390767-1-Penny.Zheng@amd.com/
>   - https://patchew.org/Xen/20250528091708.390767-1-Penny.Zheng@amd.com/
> 
> * Physical address hypercall ABI ("HVMv2")
>   - Teddy Astie
>   - https://lore.kernel.org/xen-devel/cover.1744981654.git.teddy.astie@vates.tech/
> 
> * xen: Untangle mm.h
>   -  Andrew Cooper
>   - https://lore.kernel.org/xen-devel/20250312174513.4075066-1-andrew.cooper3@citrix.com/
>   -
> https://patchew.org/Xen/20250312174513.4075066-1-andrew.cooper3@citrix.com/
> 
> * Add support for exact-node memory claims
>   -  Alejandro Vallejo
>   - https://lore.kernel.org/xen-devel/20250314172502.53498-1-alejandro.vallejo@cloud.com/
>   -
> https://patchew.org/Xen/20250314172502.53498-1-alejandro.vallejo@cloud.com/
> 
> * Several CI cleanups and improvements, plus yet another new runner
>   - Marek Marczykowski-Górecki
>   - https://lore.kernel.org/xen-devel/cover.7da1777882774486a13e6f39ff4a2096f6b7901e.1744028549.git-series.marmarek@invisiblethingslab.com/
>   - https://patchew.org/Xen/cover.7da1777882774486a13e6f39ff4a2096f6b7901e.1744028549.git-series.marmarek@invisiblethingslab.com/
> 
> *  Remove the directmap (v5)
>   -  Alejandro Vallejo
>   - https://lore.kernel.org/xen-devel/20250108151822.16030-1-alejandro.vallejo@cloud.com/
>   -
> https://patchew.org/Xen/20250108151822.16030-1-alejandro.vallejo@cloud.com/

Since you keep track of the directmap removal, you might also add the
other ASI related series:

https://lore.kernel.org/xen-devel/20250108142659.99490-1-roger.pau@citrix.com/

I very much doubt I will have time to work on this before the next
release.

Thanks, Roger.