From: Roman Kisel <romank@linux.microsoft.com>
To: arnd@arndb.de, bhelgaas@google.com, bp@alien8.de,
catalin.marinas@arm.com, conor+dt@kernel.org,
dave.hansen@linux.intel.com, decui@microsoft.com,
haiyangz@microsoft.com, hpa@zytor.com, krzk+dt@kernel.org,
kw@linux.com, kys@microsoft.com, lpieralisi@kernel.org,
manivannan.sadhasivam@linaro.org, mingo@redhat.com,
robh@kernel.org, ssengar@linux.microsoft.com, tglx@linutronix.de,
wei.liu@kernel.org, will@kernel.org, devicetree@vger.kernel.org,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, x86@kernel.org
Cc: benhill@microsoft.com, bperkins@microsoft.com, sunilmut@microsoft.com
Subject: [PATCH hyperv-next v4 0/6] arm64: hyperv: Support Virtual Trust Level Boot
Date: Tue, 11 Feb 2025 17:43:15 -0800 [thread overview]
Message-ID: <20250212014321.1108840-1-romank@linux.microsoft.com> (raw)
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.
[V4]
- 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 (6):
arm64: hyperv: Use SMCCC to detect hypervisor presence
Drivers: hv: Enable VTL mode for arm64
Drivers: hv: Provide arch-neutral implementation of get_vtl()
dt-bindings: microsoft,vmbus: Add GIC and DMA coherence to the example
Drivers: hv: vmbus: Get the IRQ number from DeviceTree
PCI: hv: Get vPCI MSI IRQ domain from DeviceTree
.../bindings/bus/microsoft,vmbus.yaml | 11 +++
arch/arm64/hyperv/mshyperv.c | 43 ++++++++++--
arch/arm64/include/asm/mshyperv.h | 5 ++
arch/x86/hyperv/hv_init.c | 34 ---------
drivers/hv/Kconfig | 10 +--
drivers/hv/hv_common.c | 32 +++++++++
drivers/hv/vmbus_drv.c | 59 +++++++++++++---
drivers/pci/controller/pci-hyperv.c | 69 +++++++++++++++++--
include/asm-generic/mshyperv.h | 6 ++
include/hyperv/hvgdk_mini.h | 2 +-
include/linux/hyperv.h | 2 +
11 files changed, 215 insertions(+), 58 deletions(-)
base-commit: 2e03358be78b65d28b66e17aca9e0c8700b0df78
--
2.43.0
next reply other threads:[~2025-02-12 1:43 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-12 1:43 Roman Kisel [this message]
2025-02-12 1:43 ` [PATCH hyperv-next v4 1/6] arm64: hyperv: Use SMCCC to detect hypervisor presence Roman Kisel
2025-02-12 6:54 ` Arnd Bergmann
2025-02-13 23:23 ` Roman Kisel
2025-02-14 8:05 ` Arnd Bergmann
2025-02-14 16:47 ` Roman Kisel
2025-02-24 23:22 ` Roman Kisel
2025-02-25 7:24 ` Arnd Bergmann
2025-02-25 22:25 ` Roman Kisel
2025-02-26 13:57 ` Arnd Bergmann
2025-02-19 23:13 ` Michael Kelley
2025-02-20 16:34 ` Roman Kisel
2025-02-12 1:43 ` [PATCH hyperv-next v4 2/6] Drivers: hv: Enable VTL mode for arm64 Roman Kisel
2025-02-19 23:14 ` Michael Kelley
2025-02-20 16:36 ` Roman Kisel
2025-02-12 1:43 ` [PATCH hyperv-next v4 3/6] Drivers: hv: Provide arch-neutral implementation of get_vtl() Roman Kisel
2025-02-19 23:17 ` Michael Kelley
2025-02-12 1:43 ` [PATCH hyperv-next v4 4/6] dt-bindings: microsoft,vmbus: Add GIC and DMA coherence to the example Roman Kisel
2025-02-12 6:42 ` Krzysztof Kozlowski
2025-02-12 23:57 ` Roman Kisel
2025-02-13 20:50 ` Roman Kisel
2025-02-12 1:43 ` [PATCH hyperv-next v4 5/6] Drivers: hv: vmbus: Get the IRQ number from DeviceTree Roman Kisel
2025-02-19 23:20 ` Michael Kelley
2025-02-12 1:43 ` [PATCH hyperv-next v4 6/6] PCI: hv: Get vPCI MSI IRQ domain " Roman Kisel
2025-02-12 17:42 ` Bjorn Helgaas
2025-02-18 22:32 ` Roman Kisel
2025-02-19 23:51 ` Roman Kisel
2025-02-19 23:29 ` Michael Kelley
2025-02-20 16:41 ` Roman Kisel
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