mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-07-24 06:50:12 -04:00
840b740a35
When the VMBus driver is not part of the kernel (CONFIG_HYPERV_VMBUS=n), the MSHV root driver fails to link: ERROR: modpost: "hv_vmbus_exists" [drivers/hv/mshv_root.ko] undefined! Fix this while meeting these requirements: * It must be possible to include the MSHV root driver without the VMBus driver. In such case, the MSHV root driver can be built-in to the kernel image, or it can be built as a separate module. * If both the MSHV root driver and the VMBus driver are present, the MSHV root driver and VMBus driver can both be built-in, or they can both be separate modules. Or the MSHV root driver can be a module while the VMBus driver can be built-in, but the reverse is disallowed. Regardless of the build choices, the VMBus driver must be loaded before the MSHV driver in order for the SynIC to be managed properly (see comments in the MSHV SynIC code). The fix has two parts: * Add a Kconfig entry for MSHV_ROOT to depend on HYPERV_VMBUS if HYPERV_VMBUS is present. The entry disallows MSHV_ROOT being built-in when HYPERV_VMBUS is a module, but without requiring that HYPERV_VMBUS be built. * Add a stub implementation of hv_vmbus_exists() for when the VMBus driver is not present so that the MSHV root driver has no module dependency on VMBus. When the VMBus driver *is* present, the module dependency ensures that the VMBus driver loads first when both are built as modules. Existing code ensures that the VMBus driver loads first if it is built-in. The VMBus driver uses subsys_initcall(), which is initcall level 4. The MSHV root driver uses module_init(), which becomes device_init() when built-in, and device_init() is initcall level 6. Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/all/20260520074044.923728-1-arnd@kernel.org/ Signed-off-by: Michael Kelley <mhklinux@outlook.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Jork Loeser <jloeser@linux.microsoft.com> Reviewed-by: Hardik Garg <hargar@linux.microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
114 lines
3.8 KiB
Plaintext
114 lines
3.8 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
|
|
|
|
menu "Microsoft Hyper-V guest support"
|
|
|
|
config HYPERV
|
|
bool "Microsoft Hyper-V core hypervisor support"
|
|
depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
|
|
|| (ARM64 && !CPU_BIG_ENDIAN)
|
|
select PARAVIRT
|
|
select X86_HV_CALLBACK_VECTOR if X86
|
|
select OF_EARLY_FLATTREE if OF
|
|
select IRQ_MSI_LIB if X86
|
|
help
|
|
Select this option to run Linux as a Hyper-V client operating
|
|
system.
|
|
|
|
config HYPERV_VTL_MODE
|
|
bool "Enable Linux to boot in VTL context"
|
|
depends on (X86_64 && HAVE_STATIC_CALL) || ARM64
|
|
depends on HYPERV
|
|
depends on SMP
|
|
default n
|
|
help
|
|
Virtual Secure Mode (VSM) is a set of hypervisor capabilities and
|
|
enlightenments offered to host and guest partitions which enables
|
|
the creation and management of new security boundaries within
|
|
operating system software.
|
|
|
|
VSM achieves and maintains isolation through Virtual Trust Levels
|
|
(VTLs). Virtual Trust Levels are hierarchical, with higher levels
|
|
being more privileged than lower levels. VTL0 is the least privileged
|
|
level, and currently only other level supported is VTL2.
|
|
|
|
Select this option to build a Linux kernel to run at a VTL other than
|
|
the normal VTL0, which currently is only VTL2. This option
|
|
initializes the kernel to run in VTL2, and adds the ability to boot
|
|
secondary CPUs directly into 64-bit context as required for VTLs other
|
|
than 0. A kernel built with this option must run at VTL2, and will
|
|
not run as a normal guest.
|
|
|
|
If unsure, say N
|
|
|
|
config HYPERV_TIMER
|
|
def_bool HYPERV && X86
|
|
|
|
config HYPERV_UTILS
|
|
tristate "Microsoft Hyper-V Utilities driver"
|
|
depends on HYPERV_VMBUS && CONNECTOR && NLS
|
|
depends on PTP_1588_CLOCK_OPTIONAL
|
|
help
|
|
Select this option to enable the Hyper-V Utilities.
|
|
|
|
config HYPERV_BALLOON
|
|
tristate "Microsoft Hyper-V Balloon driver"
|
|
depends on HYPERV_VMBUS
|
|
select PAGE_REPORTING
|
|
help
|
|
Select this option to enable Hyper-V Balloon driver.
|
|
|
|
config HYPERV_VMBUS
|
|
tristate "Microsoft Hyper-V VMBus driver"
|
|
depends on HYPERV
|
|
default HYPERV
|
|
select SYSFB if EFI && !HYPERV_VTL_MODE
|
|
help
|
|
Select this option to enable Hyper-V Vmbus driver.
|
|
|
|
config MSHV_ROOT
|
|
tristate "Microsoft Hyper-V root partition support"
|
|
depends on HYPERV && (X86_64 || ARM64)
|
|
depends on !HYPERV_VTL_MODE
|
|
# The hypervisor interface operates on 4k pages. Enforcing it here
|
|
# simplifies many assumptions in the root partition code.
|
|
# e.g. When withdrawing memory, the hypervisor gives back 4k pages in
|
|
# no particular order, making it impossible to reassemble larger pages
|
|
depends on PAGE_SIZE_4KB
|
|
depends on HYPERV_VMBUS if HYPERV_VMBUS
|
|
select EVENTFD
|
|
select VIRT_XFER_TO_GUEST_WORK
|
|
select HMM_MIRROR
|
|
select MMU_NOTIFIER
|
|
default n
|
|
help
|
|
Select this option to enable support for booting and running as root
|
|
partition on Microsoft Hyper-V.
|
|
|
|
If unsure, say N.
|
|
|
|
config MSHV_VTL
|
|
tristate "Microsoft Hyper-V VTL driver"
|
|
depends on X86_64 && HYPERV_VTL_MODE
|
|
depends on HYPERV_VMBUS
|
|
# Mapping VTL0 memory to a userspace process in VTL2 is supported in OpenHCL.
|
|
# VTL2 for OpenHCL makes use of Huge Pages to improve performance on VMs,
|
|
# specially with large memory requirements.
|
|
depends on TRANSPARENT_HUGEPAGE
|
|
# MTRRs are controlled by VTL0, and are not specific to individual VTLs.
|
|
# Therefore, do not attempt to access or modify MTRRs here.
|
|
depends on !MTRR
|
|
select CPUMASK_OFFSTACK
|
|
select VIRT_XFER_TO_GUEST_WORK
|
|
default n
|
|
help
|
|
Select this option to enable Hyper-V VTL driver support.
|
|
This driver provides interfaces for Virtual Machine Manager (VMM) running in VTL2
|
|
userspace to create VTLs and partitions, setup and manage VTL0 memory and
|
|
allow userspace to make direct hypercalls. This also allows to map VTL0's address
|
|
space to a usermode process in VTL2 and supports getting new VMBus messages and channel
|
|
events in VTL2.
|
|
|
|
If unsure, say N.
|
|
|
|
endmenu
|