Merge tag 'hyperv-next-signed-20251006' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Unify guest entry code for KVM and MSHV (Sean Christopherson)

 - Switch Hyper-V MSI domain to use msi_create_parent_irq_domain()
   (Nam Cao)

 - Add CONFIG_HYPERV_VMBUS and limit the semantics of CONFIG_HYPERV
   (Mukesh Rathor)

 - Add kexec/kdump support on Azure CVMs (Vitaly Kuznetsov)

 - Deprecate hyperv_fb in favor of Hyper-V DRM driver (Prasanna
   Kumar T S M)

 - Miscellaneous enhancements, fixes and cleanups (Abhishek Tiwari,
   Alok Tiwari, Nuno Das Neves, Wei Liu, Roman Kisel, Michael Kelley)

* tag 'hyperv-next-signed-20251006' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  hyperv: Remove the spurious null directive line
  MAINTAINERS: Mark hyperv_fb driver Obsolete
  fbdev/hyperv_fb: deprecate this in favor of Hyper-V DRM driver
  Drivers: hv: Make CONFIG_HYPERV bool
  Drivers: hv: Add CONFIG_HYPERV_VMBUS option
  Drivers: hv: vmbus: Fix typos in vmbus_drv.c
  Drivers: hv: vmbus: Fix sysfs output format for ring buffer index
  Drivers: hv: vmbus: Clean up sscanf format specifier in target_cpu_store()
  x86/hyperv: Switch to msi_create_parent_irq_domain()
  mshv: Use common "entry virt" APIs to do work in root before running guest
  entry: Rename "kvm" entry code assets to "virt" to genericize APIs
  entry/kvm: KVM: Move KVM details related to signal/-EINTR into KVM proper
  mshv: Handle NEED_RESCHED_LAZY before transferring to guest
  x86/hyperv: Add kexec/kdump support on Azure CVMs
  Drivers: hv: Simplify data structures for VMBus channel close message
  Drivers: hv: util: Cosmetic changes for hv_utils_transport.c
  mshv: Add support for a new parent partition configuration
  clocksource: hyper-v: Skip unnecessary checks for the root partition
  hyperv: Add missing field to hv_output_map_device_interrupt

1 files changed, 46 insertions, 0 deletions

diff --git a/kernel/entry/virt.c b/kernel/entry/virt.c
new file mode 100644
index 000000000000..c52f99249763
--- /dev/null
+++ b/kernel/entry/virt.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/entry-virt.h>
+
+static int xfer_to_guest_mode_work(unsigned long ti_work)
+{
+	do {
+		int ret;
+
+		if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
+			return -EINTR;
+
+		if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY))
+			schedule();
+
+		if (ti_work & _TIF_NOTIFY_RESUME)
+			resume_user_mode_work(NULL);
+
+		ret = arch_xfer_to_guest_mode_handle_work(ti_work);
+		if (ret)
+			return ret;
+
+		ti_work = read_thread_flags();
+	} while (ti_work & XFER_TO_GUEST_MODE_WORK);
+	return 0;
+}
+
+int xfer_to_guest_mode_handle_work(void)
+{
+	unsigned long ti_work;
+
+	/*
+	 * This is invoked from the outer guest loop with interrupts and
+	 * preemption enabled.
+	 *
+	 * KVM invokes xfer_to_guest_mode_work_pending() with interrupts
+	 * disabled in the inner loop before going into guest mode. No need
+	 * to disable interrupts here.
+	 */
+	ti_work = read_thread_flags();
+	if (!(ti_work & XFER_TO_GUEST_MODE_WORK))
+		return 0;
+
+	return xfer_to_guest_mode_work(ti_work);
+}
+EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work);