Re: [PATCH 1/1] Documentation: hyperv: Remove support for guests on Hyper-V 2012/2012R2

[Naman Jain]

On 10/9/2026 8:04 AM, Michael Kelley wrote:
> Support for running Linux guests on Windows Server 2012/2012 R2 Hyper-V
> hosts and Windows 8/8.1 hosts has been removed, which includes removing
> support for operating Hyper-V synthetic timers in other than Direct Mode.
> Update the documentation to reflect these removals.
>
> Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> ---
> This patch reflects changes that are already in linux-next for merging
> into the 7.4 kernel.
>
>   Documentation/virt/hyperv/clocks.rst   | 8 ++------
>   Documentation/virt/hyperv/overview.rst | 6 +++---
>   2 files changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/virt/hyperv/clocks.rst b/Documentation/virt/hyperv/clocks.rst
> index 176043265803..9527e6073654 100644
> --- a/Documentation/virt/hyperv/clocks.rst
> +++ b/Documentation/virt/hyperv/clocks.rst
> @@ -64,12 +64,8 @@ applying the scale and offset to get the constant 10 MHz clock.
>   
>   Linux clockevents are based on Hyper-V synthetic timer 0 (stimer0).
>   While Hyper-V offers 4 synthetic timers for each CPU, Linux only uses
> -timer 0. In older versions of Hyper-V, an interrupt from stimer0
> -results in a VMBus control message that is demultiplexed by
> -vmbus_isr() as described in the Documentation/virt/hyperv/vmbus.rst
> -documentation. In newer versions of Hyper-V, stimer0 interrupts can
> -be mapped to an architectural interrupt, which is referred to as
> -"Direct Mode". Linux prefers to use Direct Mode when available. Since
> +timer 0. stimer0 is operated in what Hyper-V calls "Direct Mode"
> +where timer interrupts are mapped to an architectural interrupt. Since
>   x86/x64 doesn't support per-CPU interrupts, Direct Mode statically
>   allocates an x86 interrupt vector (HYPERV_STIMER0_VECTOR) across all CPUs
>   and explicitly codes it to call the stimer0 interrupt handler. Hence
> diff --git a/Documentation/virt/hyperv/overview.rst b/Documentation/virt/hyperv/overview.rst
> index 77408a89d1a4..c4c262b77aa3 100644
> --- a/Documentation/virt/hyperv/overview.rst
> +++ b/Documentation/virt/hyperv/overview.rst
> @@ -157,9 +157,9 @@ when accessing data shared with Hyper-V.
>   Versioning
>   ----------
>   Current Linux kernels operate correctly with older versions of
> -Hyper-V back to Windows Server 2012 Hyper-V. Support for running
> -on the original Hyper-V release in Windows Server 2008/2008 R2
> -has been removed.
> +Hyper-V back to Windows Server 2016 Hyper-V and Windows 10. Support for
> +running on Windows Server 2012/2012 R2, Windows Server 2008/2008 R2,
> +and Windows 8.1 and earlier has been removed.
>   
>   A Linux guest on Hyper-V outputs in dmesg the version of Hyper-V
>   it is running on.  This version is in the form of a Windows build

Thanks Michael. Change LGTM, but while at it, please add a similar 
change in 
Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst as 
well.

Reviewed-by: Naman Jain <namjain@xxxxxxxxxxxxxxxxxxx>

Regards,
Naman