kernel/linux.git/arch/arm64/hyperv, branch v6.19.11

arm64, x86: hyperv: Report the VTL the system boots in

2025-05-23T16:30:55+00:00

The hyperv guest code might run in various Virtual Trust Levels. Report the level when the kernel boots in the non-default (0) one. Signed-off-by: Roman Kisel Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20250428210742.435282-7-romank@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20250428210742.435282-7-romank@linux.microsoft.com>

arm64: hyperv: Initialize the Virtual Trust Level field

2025-05-23T16:30:55+00:00

Various parts of the hyperv code need to know what VTL the kernel runs at, most notably VMBus needs that to establish communication with the host. Initialize the Virtual Trust Level field to enable booting in the Virtual Trust Level. Signed-off-by: Roman Kisel Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20250428210742.435282-6-romank@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20250428210742.435282-6-romank@linux.microsoft.com>

arm64: hyperv: Use SMCCC to detect hypervisor presence

2025-05-23T16:30:55+00:00

The arm64 Hyper-V startup path relies on ACPI to detect running under a Hyper-V compatible hypervisor. That doesn't work on non-ACPI systems. Hoist the ACPI detection logic into a separate function. Then use the vendor-specific hypervisor service call (implemented recently in Hyper-V) via SMCCC in the non-ACPI case. Signed-off-by: Roman Kisel Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20250428210742.435282-3-romank@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20250428210742.435282-3-romank@linux.microsoft.com>

Drivers: hv: Export some functions for use by root partition module

2025-03-20T21:23:04+00:00

hv_get_hypervisor_version(), hv_call_deposit_pages(), and hv_call_create_vp(), are all needed in-module with CONFIG_MSHV_ROOT=m. Signed-off-by: Nuno Das Neves Reviewed-by: Stanislav Kinsburskii Reviewed-by: Roman Kisel Reviewed-by: Easwar Hariharan Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/1741980536-3865-7-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-7-git-send-email-nunodasneves@linux.microsoft.com>

arm64/hyperv: Add some missing functions to arm64

2025-03-20T21:23:03+00:00

These non-nested msr and fast hypercall functions are present in x86, but they must be available in both architectures for the root partition driver code. While at it, remove the redundant 'extern' keywords from the hv_do_hypercall() variants in asm-generic/mshyperv.h. Signed-off-by: Nuno Das Neves Reviewed-by: Stanislav Kinsburskii Reviewed-by: Roman Kisel Link: https://lore.kernel.org/r/1741980536-3865-4-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-4-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Change hv_root_partition into a function

2025-02-22T02:21:45+00:00

Introduce hv_curr_partition_type to store the partition type as an enum. Right now this is limited to guest or root partition, but there will be other kinds in future and the enum is easily extensible. Set up hv_curr_partition_type early in Hyper-V initialization with hv_identify_partition_type(). hv_root_partition() just queries this value, and shouldn't be called before that. Making this check into a function sets the stage for adding a config option to gate the compilation of root partition code. In particular, hv_root_partition() can be stubbed out always be false if root partition support isn't desired. Signed-off-by: Nuno Das Neves Reviewed-by: Easwar Hariharan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Move hv_current_partition_id to arch-generic code

2025-02-13T23:38:47+00:00

Move hv_current_partition_id and hv_get_partition_id() to hv_common.c, and call hv_get_partition_id() on arm64 in hyperv_init(). These aren't specific to x86_64 and will be needed by common code. Set hv_current_partition_id to HV_PARTITION_ID_SELF by default. Rename struct hv_get_partition_id to hv_output_get_partition_id, to make it distinct from the function hv_get_partition_id(), and match the original Hyper-V struct name. Remove the BUG()s. Failing to get the id need not crash the machine. Signed-off-by: Nuno Das Neves Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1738955002-20821-2-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1738955002-20821-2-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h

2025-01-10T00:54:21+00:00

Switch to using hvhdk.h everywhere in the kernel. This header includes all the new Hyper-V headers in include/hyperv, which form a superset of the definitions found in hyperv-tlfs.h. This makes it easier to add new Hyper-V interfaces without being restricted to those in the TLFS doc (reflected in hyperv-tlfs.h). To be more consistent with the original Hyper-V code, the names of some definitions are changed slightly. Update those where needed. Update comments in mshyperv.h files to point to include/hyperv for adding new definitions. Signed-off-by: Nuno Das Neves Reviewed-by: Michael Kelley Reviewed-by: Easwar Hariharan Signed-off-by: Roman Kisel Reviewed-by: Easwar Hariharan Link: https://lore.kernel.org/r/1732577084-2122-5-git-send-email-nunodasneves@linux.microsoft.com Link: https://lore.kernel.org/r/20250108222138.1623703-3-romank@linux.microsoft.com Signed-off-by: Wei Liu

hyperv: Clean up unnecessary #includes

2025-01-08T08:18:27+00:00

Remove includes of linux/hyperv.h, mshyperv.h, and hyperv-tlfs.h where they are not used. Signed-off-by: Nuno Das Neves Acked-by: Wei Liu Reviewed-by: Michael Kelley Reviewed-by: Easwar Hariharan Link: https://lore.kernel.org/r/1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com>

x86/hyperv: Use Hyper-V entropy to seed guest random number generator

2024-03-18T22:01:52+00:00

A Hyper-V host provides its guest VMs with entropy in a custom ACPI table named "OEM0". The entropy bits are updated each time Hyper-V boots the VM, and are suitable for seeding the Linux guest random number generator (rng). See a brief description of OEM0 in [1]. Generation 2 VMs on Hyper-V use UEFI to boot. Existing EFI code in Linux seeds the rng with entropy bits from the EFI_RNG_PROTOCOL. Via this path, the rng is seeded very early during boot with good entropy. The ACPI OEM0 table provided in such VMs is an additional source of entropy. Generation 1 VMs on Hyper-V boot from BIOS. For these VMs, Linux doesn't currently get any entropy from the Hyper-V host. While this is not fundamentally broken because Linux can generate its own entropy, using the Hyper-V host provided entropy would get the rng off to a better start and would do so earlier in the boot process. Improve the rng seeding for Generation 1 VMs by having Hyper-V specific code in Linux take advantage of the OEM0 table to seed the rng. For Generation 2 VMs, use the OEM0 table to provide additional entropy beyond the EFI_RNG_PROTOCOL. Because the OEM0 table is custom to Hyper-V, parse it directly in the Hyper-V code in the Linux kernel and use add_bootloader_randomness() to add it to the rng. Once the entropy bits are read from OEM0, zero them out in the table so they don't appear in /sys/firmware/acpi/tables/OEM0 in the running VM. The zero'ing is done out of an abundance of caution to avoid potential security risks to the rng. Also set the OEM0 data length to zero so a kexec or other subsequent use of the table won't try to use the zero'ed bits. [1] https://download.microsoft.com/download/1/c/9/1c9813b8-089c-4fef-b2ad-ad80e79403ba/Whitepaper%20-%20The%20Windows%2010%20random%20number%20generation%20infrastructure.pdf Signed-off-by: Michael Kelley Reviewed-by: Jason A. Donenfeld Link: https://lore.kernel.org/r/20240318155408.216851-1-mhklinux@outlook.com Signed-off-by: Wei Liu Message-ID: <20240318155408.216851-1-mhklinux@outlook.com>