[PATCH v2 2/7] Drivers: hv: Disentangle VTL return cancellation from SIGPENDING

[Sean Christopherson]

Check for return to a lower VTL being cancelled separately from handling
pending TIF-based work, as there is no need to immediately process pending
work; the kernel will immediately exit to userspace (ignoring preemption)
and handle the pending work at that time.

Disentangling cancellation from the TIF-based work will allow switching to
common virtualization APIs for detecting and processing pending work.

Signed-off-by: Sean Christopherson <seanjc at google.com>
---
 drivers/hv/mshv_vtl_main.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c
index 12f5e77b7095..aa09a76f0eff 100644
--- a/drivers/hv/mshv_vtl_main.c
+++ b/drivers/hv/mshv_vtl_main.c
@@ -731,19 +731,21 @@ static int mshv_vtl_ioctl_return_to_lower_vtl(void)
 						_TIF_NOTIFY_RESUME | _TIF_NOTIFY_SIGNAL |
 						_TIF_NEED_RESCHED_LAZY;
 		unsigned long ti_work;
-		u32 cancel;
 		unsigned long irq_flags;
 		struct hv_vp_assist_page *hvp;
 		int ret;
 
 		local_irq_save(irq_flags);
+		if (READ_ONCE(mshv_vtl_this_run()->cancel)) {
+			local_irq_restore(irq_flags);
+			preempt_enable();
+			return -EINTR;
+		}
+
 		ti_work = READ_ONCE(current_thread_info()->flags);
-		cancel = READ_ONCE(mshv_vtl_this_run()->cancel);
-		if (unlikely((ti_work & VTL0_WORK) || cancel)) {
+		if (unlikely(ti_work & VTL0_WORK)) {
 			local_irq_restore(irq_flags);
 			preempt_enable();
-			if (cancel)
-				ti_work |= _TIF_SIGPENDING;
 			ret = mshv_do_pre_guest_mode_work(ti_work);
 			if (ret)
 				return ret;
-- 
2.51.0.268.g9569e192d0-goog