4dc8c9de38
KVM/arm64 makes use of the SMCCC "Vendor Specific Hypervisor Service Call Range" to expose KVM-specific hypercalls to guests in a discoverable and extensible fashion. Document the existence of this interface and the discovery hypercall. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-28-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
47 lines
2.5 KiB
ReStructuredText
47 lines
2.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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===============================================
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KVM/arm64-specific hypercalls exposed to guests
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===============================================
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This file documents the KVM/arm64-specific hypercalls which may be
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exposed by KVM/arm64 to guest operating systems. These hypercalls are
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issued using the HVC instruction according to version 1.1 of the Arm SMC
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Calling Convention (DEN0028/C):
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https://developer.arm.com/docs/den0028/c
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All KVM/arm64-specific hypercalls are allocated within the "Vendor
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Specific Hypervisor Service Call" range with a UID of
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``28b46fb6-2ec5-11e9-a9ca-4b564d003a74``. This UID should be queried by the
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guest using the standard "Call UID" function for the service range in
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order to determine that the KVM/arm64-specific hypercalls are available.
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``ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID``
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---------------------------------------------
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Provides a discovery mechanism for other KVM/arm64 hypercalls.
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+---------------------+-------------------------------------------------------------+
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| Presence: | Mandatory for the KVM/arm64 UID |
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+---------------------+-------------------------------------------------------------+
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| Calling convention: | HVC32 |
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+---------------------+----------+--------------------------------------------------+
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| Function ID: | (uint32) | 0x86000000 |
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+---------------------+----------+--------------------------------------------------+
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| Arguments: | None |
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+---------------------+----------+----+---------------------------------------------+
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| Return Values: | (uint32) | R0 | Bitmap of available function numbers 0-31 |
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| +----------+----+---------------------------------------------+
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| | (uint32) | R1 | Bitmap of available function numbers 32-63 |
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| +----------+----+---------------------------------------------+
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| | (uint32) | R2 | Bitmap of available function numbers 64-95 |
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| +----------+----+---------------------------------------------+
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| | (uint32) | R3 | Bitmap of available function numbers 96-127 |
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+---------------------+----------+----+---------------------------------------------+
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``ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID``
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----------------------------------------
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See ptp_kvm.rst
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