linux-kernel - [PATCH 5/5] Drivers: hv: Use common "entry virt" APIs to do work before running guest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250825200622.3759571-6-seanjc@google.com>
Date: Mon, 25 Aug 2025 13:06:22 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
	Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>, 
	Huacai Chen <chenhuacai@...nel.org>, Anup Patel <anup@...infault.org>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	Albert Ou <aou@...s.berkeley.edu>, Sean Christopherson <seanjc@...gle.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"K. Y. Srinivasan" <kys@...rosoft.com>, Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>, 
	Dexuan Cui <decui@...rosoft.com>, Peter Zijlstra <peterz@...radead.org>, 
	Andy Lutomirski <luto@...nel.org>, "Paul E. McKenney" <paulmck@...nel.org>, 
	Frederic Weisbecker <frederic@...nel.org>, Neeraj Upadhyay <neeraj.upadhyay@...nel.org>, 
	Joel Fernandes <joelagnelf@...dia.com>, Josh Triplett <josh@...htriplett.org>, 
	Boqun Feng <boqun.feng@...il.com>, Uladzislau Rezki <urezki@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, kvm@...r.kernel.org, loongarch@...ts.linux.dev, 
	kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org, 
	linux-hyperv@...r.kernel.org, rcu@...r.kernel.org
Subject: [PATCH 5/5] Drivers: hv: Use common "entry virt" APIs to do work
 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@...gle.com>
---
 drivers/hv/Kconfig          |  1 +
 drivers/hv/mshv.h           |  2 --
 drivers/hv/mshv_common.c    | 45 -------------------------------------
 drivers/hv/mshv_root_main.c |  9 +++++---
 4 files changed, 7 insertions(+), 50 deletions(-)

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 57623ca7f350..cdb210cd3710 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 db3aa3831c43..d4813df92b9c 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(void);
-
 #endif /* _MSHV_H */
diff --git a/drivers/hv/mshv_common.c b/drivers/hv/mshv_common.c
index b953b5e21110..aa2be51979fd 100644
--- a/drivers/hv/mshv_common.c
+++ b/drivers/hv/mshv_common.c
@@ -138,48 +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.
- */
-static 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;
-}
-
-int mshv_do_pre_guest_mode_work(void)
-{
-	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;
-
-}
-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 6f677fb93af0..387491ca16d6 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>
@@ -507,9 +508,11 @@ static long mshv_run_vp_with_root_scheduler(struct mshv_vp *vp)
 		u32 flags = 0;
 		struct hv_output_dispatch_vp output;
 
-		ret = mshv_do_pre_guest_mode_work();
-		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;
-- 
2.51.0.261.g7ce5a0a67e-goog