This patch set enables the Hyper-V code to boot on ARM64 inside a Virtual Trust Level. These levels are a part of the Virtual Secure Mode documented in the Top-Level Functional Specification available at https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/vsm [V3] - Employed the SMC recently implemented in the Microsoft Hyper-V hypervisor to detect running on Hyper-V/arm64. No dependence on ACPI/DT is needed anymore although the source code still falls back to ACPI as the new hypervisor might be available only in the Windows Insiders channel just yet. - As a part of the above, refactored detecting the hypervisor via ACPI FADT. - There was a suggestion to explore whether it is feasible or not to express that ACPI must be absent for the VTL mode and present for the regular guests in the Hyper-V Kconfig file. My current conclusion is that this will require refactoring in many places. That becomes especially convoluted on x86_64 due to the MSI and APIC dependencies. I'd ask to let us tackle that in another patch series (or chalk up to nice-have's rather than fires to put out) to separate concerns and decrease chances of breakage. - While refactoring `get_vtl(void)` and the related code, fixed the hypercall output address not to overlap with the input as the Hyper-V TLFS mandates: "The input and output parameter lists cannot overlap or cross page boundaries." See https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/hypercall-interface for more. Some might argue that should've been a topic for a separate patch series; I'd counter that the change is well-contained (one line), has no dependencies, and makes the code legal. - Made the VTL boot code (c)leaner as was suggested. - Set DMA cache coherency for the VMBus. - Updated DT bindings in the VMBus documentation (separated out into a new patch). - Fixed `vmbus_set_irq` to use the API that works both for the ACPI and OF. - Reworked setting up the vPCI MSI IRQ domain in the non-ACPI case. The logic looks a bit fiddly/ad-hoc as I couldn't find the API that would fit the bill. Added comments to explain myself. [V2] https://lore.kernel.org/all/20240514224508.212318-1-romank@xxxxxxxxxxxxxxxxxxx/ - Decreased number of #ifdef's - Updated the wording in the commit messages to adhere to the guidlines - Sending to the correct set of maintainers and mail lists [V1] https://lore.kernel.org/all/20240510160602.1311352-1-romank@xxxxxxxxxxxxxxxxxxx/ For validation, I built kernels for the arch'es in question with the small initrd embedded into the kernel and booted the Hyper-V VMs off of that. Roman Kisel (7): arm64: hyperv: Use SMC to detect hypervisor presence Drivers: hv: Enable VTL mode for arm64 Drivers: hv: Provide arch-neutral implementation of get_vtl() arm64: hyperv: Boot in a Virtual Trust Level dt-bindings: bus: Add Hyper-V VMBus cache coherency and IRQs Drivers: hv: vmbus: Get the IRQ number from DT PCI: hv: Get vPCI MSI IRQ domain from DT .../bindings/bus/microsoft,vmbus.yaml | 11 +++ arch/arm64/hyperv/Makefile | 1 + arch/arm64/hyperv/hv_vtl.c | 13 ++++ arch/arm64/hyperv/mshyperv.c | 40 +++++++++-- arch/arm64/include/asm/mshyperv.h | 12 ++++ arch/x86/hyperv/hv_init.c | 34 --------- arch/x86/include/asm/hyperv-tlfs.h | 7 -- drivers/hv/Kconfig | 6 +- drivers/hv/hv_common.c | 47 +++++++++++- drivers/hv/vmbus_drv.c | 72 ++++++++++++++++--- drivers/pci/controller/pci-hyperv.c | 55 +++++++++++++- include/asm-generic/hyperv-tlfs.h | 7 ++ include/asm-generic/mshyperv.h | 6 ++ include/linux/hyperv.h | 2 + 14 files changed, 251 insertions(+), 62 deletions(-) create mode 100644 arch/arm64/hyperv/hv_vtl.c base-commit: 831bcbcead6668ebf20b64fdb27518f1362ace3a -- 2.34.1
