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

[Michael Kelley <mhkelley58@gmail.com>]

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@outlook.com>
---
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
-- 
2.25.1