linux/include/asm-generic/mshyperv.h, branch v6.17

Drivers: hv: Remove hv_alloc/free_* helpers

2025-05-23T16:30:56Z

There are no users for those functions, remove them. Signed-off-by: Long Li Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1746492997-4599-6-git-send-email-longli@linuxonhyperv.com Signed-off-by: Wei Liu Message-ID: <1746492997-4599-6-git-send-email-longli@linuxonhyperv.com>

Drivers: hv: Provide arch-neutral implementation of get_vtl()

2025-05-23T16:30:55Z

To run in the VTL mode, Hyper-V drivers have to know what VTL the system boots in, and the arm64/hyperv code does not have the means to compute that. Refactor the code to hoist the function that detects VTL, make it arch-neutral to be able to employ it to get the VTL on arm64. Signed-off-by: Roman Kisel Reviewed-by: Michael Kelley Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/20250428210742.435282-5-romank@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20250428210742.435282-5-romank@linux.microsoft.com>

x86: hyperv: Add mshv_handler() irq handler and setup function

2025-03-20T21:23:04Z

Add mshv_handler() to process messages related to managing guest partitions such as intercepts, doorbells, and scheduling messages. In a (non-nested) root partition, the same interrupt vector is shared between the vmbus and mshv_root drivers. Introduce a stub for mshv_handler() and call it in sysvec_hyperv_callback alongside vmbus_handler(). Even though both handlers will be called for every Hyper-V interrupt, the messages for each driver are delivered to different offsets within the SYNIC message page, so they won't step on each other. Signed-off-by: Nuno Das Neves Reviewed-by: Wei Liu Reviewed-by: Tianyu Lan Reviewed-by: Stanislav Kinsburskii Link: https://lore.kernel.org/r/1741980536-3865-9-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-9-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Introduce hv_recommend_using_aeoi()

2025-03-20T21:23:04Z

Factor out the check for enabling auto eoi, to be reused in root partition code. No functional changes. Signed-off-by: Nuno Das Neves Reviewed-by: Stanislav Kinsburskii Reviewed-by: Easwar Hariharan Reviewed-by: Michael Kelley Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/1741980536-3865-5-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-5-git-send-email-nunodasneves@linux.microsoft.com>

arm64/hyperv: Add some missing functions to arm64

2025-03-20T21:23:03Z

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>

x86/mshyperv: Add support for extended Hyper-V features

2025-03-20T21:23:03Z

Extend the "ms_hyperv_info" structure to include a new field, "ext_features", for capturing extended Hyper-V features. Update the "ms_hyperv_init_platform" function to retrieve these features using the cpuid instruction and include them in the informational output. Signed-off-by: Stanislav Kinsburskii Signed-off-by: Nuno Das Neves Reviewed-by: Easwar Hariharan Reviewed-by: Roman Kisel Reviewed-by: Tianyu Lan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1741980536-3865-3-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-3-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Log hypercall status codes as strings

2025-03-20T21:23:03Z

Introduce hv_status_printk() macros as a convenience to log hypercall errors, formatting them with the status code (HV_STATUS_*) as a raw hex value and also as a string, which saves some time while debugging. Create a table of HV_STATUS_ codes with strings and mapped errnos, and use it for hv_result_to_string() and hv_result_to_errno(). Use the new hv_status_printk()s in hv_proc.c, hyperv-iommu.c, and irqdomain.c hypercalls to aid debugging in the root partition. Signed-off-by: Nuno Das Neves Reviewed-by: Stanislav Kinsburskii Link: https://lore.kernel.org/r/1741980536-3865-2-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1741980536-3865-2-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Add CONFIG_MSHV_ROOT to gate root partition support

2025-03-20T21:22:58Z

CONFIG_MSHV_ROOT allows kernels built to run as a normal Hyper-V guest to exclude the root partition code, which is expected to grow significantly over time. This option is a tristate so future driver code can be built as a (m)odule, allowing faster development iteration cycles. If CONFIG_MSHV_ROOT is disabled, don't compile hv_proc.c, and stub hv_root_partition() to return false unconditionally. This allows the compiler to optimize away root partition code blocks since they will be disabled at compile time. In the case of booting as root partition *without* CONFIG_MSHV_ROOT enabled, print a critical error (the kernel will likely crash). Signed-off-by: Nuno Das Neves Reviewed-by: Easwar Hariharan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1740167795-13296-4-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1740167795-13296-4-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Change hv_root_partition into a function

2025-02-22T02:21:45Z

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: Convert hypercall statuses to linux error codes

2025-02-22T02:21:45Z

Return linux-friendly error codes from hypercall helper functions, which allows them to be used more flexibly. Introduce hv_result_to_errno() for this purpose, which also handles the special value U64_MAX returned from hv_do_hypercall(). Signed-off-by: Nuno Das Neves Reviewed-by: Easwar Hariharan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1740167795-13296-2-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1740167795-13296-2-git-send-email-nunodasneves@linux.microsoft.com>