| Message ID | 20250428210742.435282-1-romank@linux.microsoft.com |
|---|---|
| Headers | show |
| Series | arm64: hyperv: Support Virtual Trust Level Boot | expand |
On Mon, Apr 28, 2025 at 02:07:31PM -0700, Roman Kisel wrote: > This patch set allows 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. > > The OpenHCL paravisor https://github.com/microsoft/openvmm/tree/main/openhcl > can serve as a practical application of these patches on ARM64. > > For validation, I built kernels for the {x86_64, ARM64} x {VTL0, VTL2} set with > a small initrd embedded into the kernel and booted VMs managed by Hyper-V and > OpenVMM off of that. > > Starting from V5, the patch series includes a non-functional change to KVM on > arm64 which I tested as well. > > I've kept the Acked-by tags given by Arnd and Bjorn. These patches (1 and 11) > have changed very slightly since then (V5 and V6), no functional changes: > in patch 1, removed macro's in favour of functions as Marc suggested to get rid > of "sparse" warnings, and in patch 11, fixed building as a module. Please let me > know if I should have not kept the tags. > [...] > Roman Kisel (11): > arm64: kvm, smccc: Introduce and use API for getting hypervisor UUID I notice there were review comments from multiple people on this patch. To the best of my knowledge, those comments have been addressed in this version, but I only had a cursory look and am by no means an expert on ARM64. My assumption is Arnd's review is good enough for this patch to get merged. With that assumption, I have applied this whole series to hyperv-next. ARM64 maintainers, please let me know if you have an objection -- I can drop the series and let Roman address further comments. Thanks, Wei. > arm64: hyperv: Use SMCCC to detect hypervisor presence > Drivers: hv: Enable VTL mode for arm64 > Drivers: hv: Provide arch-neutral implementation of get_vtl() > arm64: hyperv: Initialize the Virtual Trust Level field > arm64, x86: hyperv: Report the VTL the system boots in > dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence > properties > Drivers: hv: vmbus: Get the IRQ number from DeviceTree > Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device() > ACPI: irq: Introduce acpi_get_gsi_dispatcher() > PCI: hv: Get vPCI MSI IRQ domain from DeviceTree
This patch set allows 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. The OpenHCL paravisor https://github.com/microsoft/openvmm/tree/main/openhcl can serve as a practical application of these patches on ARM64. For validation, I built kernels for the {x86_64, ARM64} x {VTL0, VTL2} set with a small initrd embedded into the kernel and booted VMs managed by Hyper-V and OpenVMM off of that. Starting from V5, the patch series includes a non-functional change to KVM on arm64 which I tested as well. I've kept the Acked-by tags given by Arnd and Bjorn. These patches (1 and 11) have changed very slightly since then (V5 and V6), no functional changes: in patch 1, removed macro's in favour of functions as Marc suggested to get rid of "sparse" warnings, and in patch 11, fixed building as a module. Please let me know if I should have not kept the tags. [V9] - Fix building the pci-hyperv driver as a module. ** Thank you, Micheal! ** - Removed an overzealous check for the ACPI IRQ model on arm64 running with Hyper-V -- only GIC is supported. That check belongs to the lower layer code, and I took it from the ACPI driver while open-coding getting the parent IRQ domain. [V8] https://lore.kernel.org/linux-hyperv/20250414224713.1866095-1-romank@linux.microsoft.com/ - Use the Linux derfined macro __ASSEMBLY__ instead of the gcc's pre-defined macro __ASSEMBLER__ to follow the kernel coding style. ** Thank you, Marc! ** [V7] https://lore.kernel.org/linux-hyperv/20250407201336.66913-1-romank@linux.microsoft.com/ - Used another approach not to increase the number of warnings produced when building with CHECK_ENDIAN. ** Thank you, Arnd! ** - Adjusted the function parameter formatting to match the rest of the code. ** Thank you, Bjorn! ** - Removed the now unused local variable. ** Thank you, kernel robot! ** - Fixed the description in the VMBus DT binding patch. ** Thank you, Krzysztof! ** - Adjusted the function names and comments to better reflect what they do, used the suggested approach to handling UUIDs to make code more readable and maintainable on big-endian. - Replaced ifdeffery with a stub function to make the code more readable. ** Thank you, Mark! ** - Fixed the Kconfig not to build the VTL mode code on 32-bit kernels. ** Thank you, Michael! ** - Fixed the indentation and the comment style. ** Thank you, Rafael! ** [V6] https://lore.kernel.org/linux-hyperv/20250315001931.631210-1-romank@linux.microsoft.com/ - Use more intuitive Kconfig update. - Remove ifdef for getting IRQ number ** Thank you, Arnd! ** - Simplify code for finding the parent IRQ domain. ** Thank you, Bjorn! ** - Remove a superfluous check. ** Thank you, Dan! ** - Make the commit title and descrtiption legible. - Don't set additionalProperties to true. ** Thank you, Krzysztof! ** - Fix spelling in the commit title and description. - Trade-offs for options in Kconfig. - Export the new symbol as hyperv-pci can be built as a module. ** Thank you, Michael! ** - Simplify code for getting IRQ number. ** Thank you, Rob! ** - Add comment to clarify when running in VTL mode is reported. ** Thank you, Wei! ** [V5] https://lore.kernel.org/linux-hyperv/20250307220304.247725-1-romank@linux.microsoft.com/ - Provide and use a common SMCCC-based infra for the arm64 hypervisor guests to detect hypervisor presence. ** Thank you, Arnd! ** - Fix line wraps to follow the rest of the code. - Open-code getting IRQ domain parent in the ACPI case to make the code better. ** Thank you, Bjorn! ** - Test the binding with the latest dtschema. - Clean up the commit title and description. - Use proper defines for known constants. ** Thank you, Krzysztof! ** - Extend comment on why ACPI v6 is checked for. - Reorder patches to make sure that even with partial series application the compilation succeeds. - Report VTL the kernel runs in. - Use "X86_64" in Kconfig rather than "X86". - Extract a non-functional change for hv_get_vmbus_root_device() into a separate patch. ** Thank you, Michael! ** [V4] https://lore.kernel.org/linux-hyperv/20250212014321.1108840-1-romank@linux.microsoft.com/ - Fixed wording to match acronyms defined in the "Terms and Abbreviations" section of the SMCCC specification throughout the patch series. **Thank you, Michael!** - Replaced the hypervisor ID containing ASCII with an UUID as required by the specification. **Thank you, Michael!** - Added an explicit check for `SMCCC_RET_NOT_SUPPORTED` when discovering the hypervisor presence to make the backward compatibility obvious. **Thank you, Saurabh!** - Split the fix for `get_vtl(void)` out to make it easier to backport. - Refactored the configuration options as requested to eliminate the risk of building non-functional kernels with randomly selected options. **Thank you, Michael!** - Refactored the changes not to introduce an additional file with a one-line function. **Thank you, Wei!** - Fixed change description for the VMBus DeviceTree changes, used `scripts/get_maintainers.pl` on the latest kernel to get the up-to-date list of maintainers as requested. **Thank you, Krzysztof!** - Removed the added (paranoidal+superfluous) checks for DMA coherence in the VMBus driver and instead relied on the DMA and the OF subsystem code. **Thank you, Arnd, Krzysztof, Michael!** - Used another set of APIs for discovering the hardware interrupt number in the VMBus driver to be able to build the driver as a module. **Thank you, Michael, Saurabh!** - Renamed the newly introduced `get_vmbus_root_device(void)` function to `hv_get_vmbus_root_device(void)` as requested. **Thank you, Wei!** - Applied the suggested small-scale refactoring to simplify changes to the Hyper-V PCI driver. Taking the offered liberty of doing the large scale refactoring in another patch series. **Thank you, Michael!** - Added a fix for the issue discovered internally where the CPU would not get the interrupt from a PCI device attached to VTL2 as the shared peripheral interrupt number (SPI) was not offset by 32 (the first valid SPI number). **Thank you, Brian!** [V3] https://lore.kernel.org/lkml/20240726225910.1912537-1-romank@linux.microsoft.com/ - Employed the SMCCC function 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@linux.microsoft.com/ - 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@linux.microsoft.com/ Roman Kisel (11): arm64: kvm, smccc: Introduce and use API for getting hypervisor UUID arm64: hyperv: Use SMCCC to detect hypervisor presence Drivers: hv: Enable VTL mode for arm64 Drivers: hv: Provide arch-neutral implementation of get_vtl() arm64: hyperv: Initialize the Virtual Trust Level field arm64, x86: hyperv: Report the VTL the system boots in dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties Drivers: hv: vmbus: Get the IRQ number from DeviceTree Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device() ACPI: irq: Introduce acpi_get_gsi_dispatcher() PCI: hv: Get vPCI MSI IRQ domain from DeviceTree .../bindings/bus/microsoft,vmbus.yaml | 16 ++++- arch/arm64/hyperv/mshyperv.c | 53 ++++++++++++-- arch/arm64/kvm/hypercalls.c | 10 +-- arch/x86/hyperv/hv_init.c | 34 --------- arch/x86/hyperv/hv_vtl.c | 7 +- drivers/acpi/irq.c | 16 ++++- drivers/firmware/smccc/kvm_guest.c | 10 +-- drivers/firmware/smccc/smccc.c | 17 +++++ drivers/hv/Kconfig | 6 +- drivers/hv/hv_common.c | 31 ++++++++ drivers/hv/vmbus_drv.c | 53 +++++++++++--- drivers/pci/controller/pci-hyperv.c | 70 +++++++++++++++++-- include/asm-generic/mshyperv.h | 6 ++ include/hyperv/hvgdk_mini.h | 2 +- include/linux/acpi.h | 5 +- include/linux/arm-smccc.h | 64 +++++++++++++++-- include/linux/hyperv.h | 2 + 17 files changed, 323 insertions(+), 79 deletions(-) base-commit: 628cc040b3a2980df6032766e8ef0688e981ab95