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[174.165.208.10]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-896c4a99b28sm296770b3a.59.2026.10.08.19.34.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Oct 2026 19:34:41 -0700 (PDT) From: Michael Kelley X-Google-Original-From: Michael Kelley To: haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH 1/1] Documentation: hyperv: Remove support for guests on Hyper-V 2012/2012R2 Date: Thu, 8 Oct 2026 19:34:37 -0700 Message-Id: <20261009023437.3326-1-mhklinux@outlook.com> X-Mailer: git-send-email 2.25.1 Reply-To: mhklinux@outlook.com Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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