Running in the root partition is a unique and specialized case that requires additional code. CONFIG_MSHV_ROOT allows Hyper-V guest kernels to exclude this code, which is important since significant additional code specific to the root partition is expected to be added over time. To do this, change hv_root_partition to be a function which is stubbed out to return false if CONFIG_MSHV_ROOT=n, and don't compile hv_proc.c at all, stubbing out those functions with inline versions. Store the partition type (guest or root) in an enum hv_curr_partition_type, which can be extended beyond just guest and root partition. While at it, introduce hv_result_to_errno() to convert Hyper-V status codes to regular linux errors. This is useful because the caller of a hypercall helper function (such as those in hv_proc.c) usually can't and doesn't interpret the Hyper-V status, so it is better to convert it to an error code and reduce the possibility of misinterpreting it. This also alows the stubbed versions of the hv_proc.c functions to just return a linux error code. Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> --- Changes in v3: * Fix a typo [Easwar Hariharan] * Fix ret being initialized to HV_STATUS_SUCCESS in some hypercall helpers [Michael Kelley] * Fix CONFIG_MSHV_ROOT being used in patch 2, before it is defined [Michael Kelley] * Shorten hv_current_partition_type to hv_curr_partition_type [Mukesh Rathor] Changes in v2: * Add patch to convert hypercall statuses to linux error codes [Easwar Hariharan] * While at it, split the original patch into two logical pieces, one to change hv_root_partition into a function, and one to introduce MSHV_CONFIG_ROOT * Improve the clarity of and add an error message to hv_identify_partition_type() [Easwar Hariharan] [Michael Kelley] * Better explain *why* the patches are useful, in the commit messages [Michael Kelley] * Add a Kconfig comment explaining why PAGE_SIZE_4KB is needed [Michael Kelley] * Minor style and typo fixes Nuno Das Neves (3): hyperv: Convert hypercall statuses to linux error codes hyperv: Change hv_root_partition into a function hyperv: Add CONFIG_MSHV_ROOT to gate root partition support arch/arm64/hyperv/mshyperv.c | 2 + arch/x86/hyperv/hv_init.c | 10 ++--- arch/x86/kernel/cpu/mshyperv.c | 24 +---------- drivers/clocksource/hyperv_timer.c | 4 +- drivers/hv/Kconfig | 16 +++++++ drivers/hv/Makefile | 3 +- drivers/hv/hv.c | 10 ++--- drivers/hv/hv_common.c | 69 +++++++++++++++++++++++++++--- drivers/hv/hv_proc.c | 10 ++--- drivers/hv/vmbus_drv.c | 2 +- drivers/iommu/hyperv-iommu.c | 4 +- include/asm-generic/mshyperv.h | 40 ++++++++++++++--- 12 files changed, 139 insertions(+), 55 deletions(-) -- 2.34.1
