From 461fbbd036b11d755b50e2ef7c165859a0f908d5 Mon Sep 17 00:00:00 2001 From: Nuno Das Neves Date: Fri, 21 Feb 2025 11:56:35 -0800 Subject: hyperv: Add CONFIG_MSHV_ROOT to gate root partition support 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> --- include/asm-generic/mshyperv.h | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 54ebd630e72c..b13b0cda4ac8 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -223,10 +223,6 @@ void *hv_alloc_hyperv_page(void); void *hv_alloc_hyperv_zeroed_page(void); void hv_free_hyperv_page(void *addr); -int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); -int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); -int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); - /** * hv_cpu_number_to_vp_number() - Map CPU to VP. * @cpu_number: CPU number in Linux terms @@ -327,9 +323,29 @@ static inline enum hv_isolation_type hv_get_isolation_type(void) } #endif /* CONFIG_HYPERV */ +#if IS_ENABLED(CONFIG_MSHV_ROOT) static inline bool hv_root_partition(void) { return hv_curr_partition_type == HV_PARTITION_TYPE_ROOT; } +int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); +int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); +int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); + +#else /* CONFIG_MSHV_ROOT */ +static inline bool hv_root_partition(void) { return false; } +static inline int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages) +{ + return -EOPNOTSUPP; +} +static inline int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id) +{ + return -EOPNOTSUPP; +} +static inline int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_MSHV_ROOT */ #endif -- cgit v1.2.3