From: Sean Christopherson <seanjc@google.com>
Date: Thu, 28 Aug 2025 00:01:55 +0000 (-0700)
Subject: mshv: Use common "entry virt" APIs to do work in root before running guest
X-Git-Tag: v6.18-rc1~52^2~9
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5eebe075e1129748f74e567da7bd8fbe77e485b;p=thirdparty%2Fkernel%2Flinux.git

mshv: Use common "entry virt" APIs to do work in root before running guest

Use the kernel's common "entry virt" APIs to handle pending work prior to
(re)entering guest mode, now that the virt APIs don't have a superfluous
dependency on KVM.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
---

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 57623ca7f350a..cdb210cd3710e 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -66,6 +66,7 @@ config MSHV_ROOT
 	# no particular order, making it impossible to reassemble larger pages
 	depends on PAGE_SIZE_4KB
 	select EVENTFD
+	select VIRT_XFER_TO_GUEST_WORK
 	default n
 	help
 	  Select this option to enable support for booting and running as root
diff --git a/drivers/hv/mshv.h b/drivers/hv/mshv.h
index 0340a67acd0a4..d4813df92b9cb 100644
--- a/drivers/hv/mshv.h
+++ b/drivers/hv/mshv.h
@@ -25,6 +25,4 @@ int hv_call_set_vp_registers(u32 vp_index, u64 partition_id, u16 count,
 int hv_call_get_partition_property(u64 partition_id, u64 property_code,
 				   u64 *property_value);
 
-int mshv_do_pre_guest_mode_work(ulong th_flags);
-
 #endif /* _MSHV_H */
diff --git a/drivers/hv/mshv_common.c b/drivers/hv/mshv_common.c
index eb3df3e296bbe..aa2be51979fd6 100644
--- a/drivers/hv/mshv_common.c
+++ b/drivers/hv/mshv_common.c
@@ -138,25 +138,3 @@ int hv_call_get_partition_property(u64 partition_id,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(hv_call_get_partition_property);
-
-/*
- * Handle any pre-processing before going into the guest mode on this cpu, most
- * notably call schedule(). Must be invoked with both preemption and
- * interrupts enabled.
- *
- * Returns: 0 on success, -errno on error.
- */
-int mshv_do_pre_guest_mode_work(ulong th_flags)
-{
-	if (th_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
-		return -EINTR;
-
-	if (th_flags & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY))
-		schedule();
-
-	if (th_flags & _TIF_NOTIFY_RESUME)
-		resume_user_mode_work(NULL);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(mshv_do_pre_guest_mode_work);
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index 3d0d5af80d2ec..e3b2bd417c464 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -8,6 +8,7 @@
  * Authors: Microsoft Linux virtualization team
  */
 
+#include <linux/entry-virt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/fs.h>
@@ -481,29 +482,6 @@ mshv_vp_wait_for_hv_kick(struct mshv_vp *vp)
 	return 0;
 }
 
-static int mshv_pre_guest_mode_work(struct mshv_vp *vp)
-{
-	const ulong work_flags = _TIF_NOTIFY_SIGNAL | _TIF_SIGPENDING |
-				 _TIF_NEED_RESCHED  | _TIF_NEED_RESCHED_LAZY |
-				 _TIF_NOTIFY_RESUME;
-	ulong th_flags;
-
-	th_flags = read_thread_flags();
-	while (th_flags & work_flags) {
-		int ret;
-
-		/* nb: following will call schedule */
-		ret = mshv_do_pre_guest_mode_work(th_flags);
-
-		if (ret)
-			return ret;
-
-		th_flags = read_thread_flags();
-	}
-
-	return 0;
-}
-
 /* Must be called with interrupts enabled */
 static long mshv_run_vp_with_root_scheduler(struct mshv_vp *vp)
 {
@@ -524,9 +502,11 @@ static long mshv_run_vp_with_root_scheduler(struct mshv_vp *vp)
 		u32 flags = 0;
 		struct hv_output_dispatch_vp output;
 
-		ret = mshv_pre_guest_mode_work(vp);
-		if (ret)
-			break;
+		if (__xfer_to_guest_mode_work_pending()) {
+			ret = xfer_to_guest_mode_handle_work();
+			if (ret)
+				break;
+		}
 
 		if (vp->run.flags.intercept_suspend)
 			flags |= HV_DISPATCH_VP_FLAG_CLEAR_INTERCEPT_SUSPEND;