RE: [PATCH hyperv-next v4 2/6] Drivers: hv: Enable VTL mode for arm64
From: Michael Kelley
Date: Wed Feb 19 2025 - 18:15:49 EST
From: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> Sent: Tuesday, February 11, 2025 5:43 PM
>
> Kconfig dependencies for arm64 guests on Hyper-V require that be
> ACPI enabled, and limit VTL mode to x86/x64. To enable VTL mode
> on arm64 as well, update the dependencies. Since VTL mode requires
> DeviceTree instead of ACPI, don't require arm64 guests on Hyper-V
> to have ACPI unconditionally.
>
> Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/hv/Kconfig | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 862c47b191af..db9912ef96a8 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -5,18 +5,20 @@ menu "Microsoft Hyper-V guest support" config HYPERV
> tristate "Microsoft Hyper-V client drivers"
> depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> - || (ACPI && ARM64 && !CPU_BIG_ENDIAN)
> + || (ARM64 && !CPU_BIG_ENDIAN)
> + depends on (ACPI || HYPERV_VTL_MODE)
> select PARAVIRT
> select X86_HV_CALLBACK_VECTOR if X86
> - select OF_EARLY_FLATTREE if OF
> 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 && HYPERV
> + depends on (X86 || ARM64)
Any reason to choose "X86" instead of "X86_64"? I can't
imagine VTL mode making any sense for 32-bit, but maybe
I'm wrong! :-)
> depends on SMP
> + select OF_EARLY_FLATTREE
> + select OF
> default n
> help
> Virtual Secure Mode (VSM) is a set of hypervisor capabilities and
> @@ -31,7 +33,7 @@ config HYPERV_VTL_MODE
>
> 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 x86 platform for VTL2, and adds the ability to boot
> + 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.
> --
> 2.43.0
>