kernel/linux.git/arch/x86/hyperv, branch v6.19.11

x86/hyperv: Use __naked attribute to fix stackless C function

2026-03-25T10:13:30+00:00

[ Upstream commit 3fde5281b805370a6c3bd2ef462ebff70a0ea2c6 ] hv_crash_c_entry() is a C function that is entered without a stack, and this is only allowed for functions that have the __naked attribute, which informs the compiler that it must not emit the usual prologue and epilogue or emit any other kind of instrumentation that relies on a stack frame. So split up the function, and set the __naked attribute on the initial part that sets up the stack, GDT, IDT and other pieces that are needed for ordinary C execution. Given that function calls are not permitted either, use the existing long return coded in an asm() block to call the second part of the function, which is an ordinary function that is permitted to call other functions as usual. Reviewed-by: Andrew Cooper # asm parts, not hv parts Reviewed-by: Mukesh Rathor Acked-by: Uros Bizjak Cc: Wei Liu Cc: linux-hyperv@vger.kernel.org Fixes: 94212d34618c ("x86/hyperv: Implement hypervisor RAM collection into vmcore") Signed-off-by: Ard Biesheuvel Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

x86/hyperv: Move hv crash init after hypercall pg setup

2026-03-04T12:20:46+00:00

[ Upstream commit c3a6ae7ea2d3f507cbddb5818ccc65b9d84d6dc7 ] hv_root_crash_init() is not setting up the hypervisor crash collection for baremetal cases because when it's called, hypervisor page is not setup. Fix is simple, just move the crash init call after the hypercall page setup. Signed-off-by: Mukesh Rathor Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

x86/hyperv: Fix error pointer dereference

2026-02-26T23:01:38+00:00

[ Upstream commit 705d01c8d78121ee1634bfc602ac4b0ad1438fab ] The function idle_thread_get() can return an error pointer and is not checked for it. Add check for error pointer. Detected by Smatch: arch/x86/hyperv/hv_vtl.c:126 hv_vtl_bringup_vcpu() error: 'idle' dereferencing possible ERR_PTR() Fixes: 2b4b90e053a29 ("x86/hyperv: Use per cpu initial stack for vtl context") Signed-off-by: Ethan Tidmore Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

x86/hyperv: Fix smp_ops build failure on UP kernels

2026-02-26T23:00:47+00:00

[ Upstream commit ac059ae422d7d05ed9d62970a30fa3b95870b967 ] CI testing found this build failure: arch/x86/hyperv/hv_crash.c:631:9: error: ‘smp_ops’ undeclared (first use in this function) And I bisected it back to the initial commit that enabled this feature: 77c860d2dbb72d1f3c6a2e882a07d19eca399db5 is the first bad commit commit 77c860d2dbb72d1f3c6a2e882a07d19eca399db5 (HEAD) Author: Mukesh Rathor Date: Mon Oct 6 15:42:08 2025 -0700 x86/hyperv: Enable build of hypervisor crashdump collection files Hyperv should probably be limited to SMP kernels, as nobody appears to be testing it on UP kernels. Until then, fix the smp_ops assumption. Build tested only. Fixes: 77c860d2dbb72 ("x86/hyperv: Enable build of hypervisor crashdump collection files") Cc: Mukesh Rathor Cc: Wei Liu Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

x86/hv: Add gitignore entry for generated header file

2025-12-13T07:57:41+00:00

Commit 7bfe3b8ea6e3 ("Drivers: hv: Introduce mshv_vtl driver") added a new generated header file for the offsets into the mshv_vtl_cpu_context structure to be used by the low-level assembly code. But it didn't add the .gitignore file to go with it, so 'git status' and friends will mention it. Let's add the gitignore file before somebody thinks that generated header should be committed. Fixes: 7bfe3b8ea6e3 ("Drivers: hv: Introduce mshv_vtl driver") Signed-off-by: Linus Torvalds

Merge tag 'hyperv-next-signed-20251207' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

2025-12-08T21:10:17+00:00

Pull hyperv updates from Wei Liu: - Enhancements to Linux as the root partition for Microsoft Hypervisor: - Support a new mode called L1VH, which allows Linux to drive the hypervisor running the Azure Host directly - Support for MSHV crash dump collection - Allow Linux's memory management subsystem to better manage guest memory regions - Fix issues that prevented a clean shutdown of the whole system on bare metal and nested configurations - ARM64 support for the MSHV driver - Various other bug fixes and cleanups - Add support for Confidential VMBus for Linux guest on Hyper-V - Secure AVIC support for Linux guests on Hyper-V - Add the mshv_vtl driver to allow Linux to run as the secure kernel in a higher virtual trust level for Hyper-V * tag 'hyperv-next-signed-20251207' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (58 commits) mshv: Cleanly shutdown root partition with MSHV mshv: Use reboot notifier to configure sleep state mshv: Add definitions for MSHV sleep state configuration mshv: Add support for movable memory regions mshv: Add refcount and locking to mem regions mshv: Fix huge page handling in memory region traversal mshv: Move region management to mshv_regions.c mshv: Centralize guest memory region destruction mshv: Refactor and rename memory region handling functions mshv: adjust interrupt control structure for ARM64 Drivers: hv: use kmalloc_array() instead of kmalloc() mshv: Add ioctl for self targeted passthrough hvcalls Drivers: hv: Introduce mshv_vtl driver Drivers: hv: Export some symbols for mshv_vtl static_call: allow using STATIC_CALL_TRAMP_STR() from assembly mshv: Extend create partition ioctl to support cpu features mshv: Allow mappings that overlap in uaddr mshv: Fix create memory region overlap check mshv: add WQ_PERCPU to alloc_workqueue users Drivers: hv: Use kmalloc_array() instead of kmalloc() ...

mshv: Use reboot notifier to configure sleep state

2025-12-05T23:25:01+00:00

Configure sleep state information from ACPI in MSHV hypervisor using a reboot notifier. This data allows the hypervisor to correctly power off the host during shutdown. Signed-off-by: Praveen K Paladugu Co-developed-by: Anatol Belski Signed-off-by: Anatol Belski Reviewed-by: Easwar Hariharan Reviewed-by: Stansialv Kinsburskii Acked-by: Ingo Molnar Reviewed-by: Nuno Das Neves Signed-off-by: Wei Liu

Drivers: hv: Introduce mshv_vtl driver

2025-12-05T23:16:26+00:00

Provide an interface for Virtual Machine Monitor like OpenVMM and its use as OpenHCL paravisor to control VTL0 (Virtual trust Level). Expose devices and support IOCTLs for features like VTL creation, VTL0 memory management, context switch, making hypercalls, mapping VTL0 address space to VTL2 userspace, getting new VMBus messages and channel events in VTL2 etc. Co-developed-by: Roman Kisel Signed-off-by: Roman Kisel Co-developed-by: Saurabh Sengar Signed-off-by: Saurabh Sengar Reviewed-by: Michael Kelley Signed-off-by: Naman Jain Signed-off-by: Wei Liu

x86/hyperv: Enable build of hypervisor crashdump collection files

2025-11-15T06:18:16+00:00

Enable build of the new files introduced in the earlier commits and add call to do the setup during boot. Signed-off-by: Mukesh Rathor [ wei: fix build ] Signed-off-by: Wei Liu

x86/hyperv: Implement hypervisor RAM collection into vmcore

2025-11-15T06:18:16+00:00

Introduce a new file to implement collection of hypervisor RAM into the vmcore collected by linux. By default, the hypervisor RAM is locked, ie, protected via hw page table. Hyper-V implements a disable hypercall which essentially devirtualizes the system on the fly. This mechanism makes the hypervisor RAM accessible to linux. Because the hypervisor RAM is already mapped into linux address space (as reserved RAM), it is automatically collected into the vmcore without extra work. More details of the implementation are available in the file prologue. Signed-off-by: Mukesh Rathor Signed-off-by: Wei Liu