entry: Rename "kvm" entry code assets to "virt" to genericize APIs

Rename the "kvm" entry code files and Kconfigs to use generic "virt"
nomenclature so that the code can be reused by other hypervisors (or
rather, their root/dom0 partition drivers), without incorrectly suggesting
the code somehow relies on and/or involves KVM.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

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);