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From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: Vineeth Pillai <vineethrp@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Aaron Lu <aaron.lwe@gmail.com>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Julien Desfossez <jdesfossez@digitalocean.com>,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Paul Turner <pjt@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tim Chen <tim.c.chen@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	fweisbec@gmail.com, kerrnel@google.com,
	Phil Auld <pauld@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Chen Yu <yu.c.chen@intel.com>,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH RFC 06/12] entry/kvm: Protect the kernel when entering from guest
Date: Fri, 14 Aug 2020 23:19:02 -0400
Message-ID: <20200815031908.1015049-7-joel@joelfernandes.org> (raw)
In-Reply-To: <20200815031908.1015049-1-joel@joelfernandes.org>

From: Vineeth Pillai <vineethrp@gmail.com>

Similar to how user to kernel mode transitions are protected in earlier
patches, protect the entry into kernel from guest mode as well.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 arch/x86/kvm/x86.c        |  3 +++
 include/linux/entry-kvm.h | 12 ++++++++++++
 kernel/entry/kvm.c        | 12 ++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 82d4a9e88908..b8a6faf78dc6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8484,6 +8484,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	 */
 	smp_mb__after_srcu_read_unlock();
 
+	kvm_exit_to_guest_mode(vcpu);
+
 	/*
 	 * This handles the case where a posted interrupt was
 	 * notified with kvm_vcpu_kick.
@@ -8578,6 +8580,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		}
 	}
 
+	kvm_enter_from_guest_mode(vcpu);
 	local_irq_enable();
 	preempt_enable();
 
diff --git a/include/linux/entry-kvm.h b/include/linux/entry-kvm.h
index 0cef17afb41a..32aabb7f3e6d 100644
--- a/include/linux/entry-kvm.h
+++ b/include/linux/entry-kvm.h
@@ -77,4 +77,16 @@ static inline bool xfer_to_guest_mode_work_pending(void)
 }
 #endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */
 
+/**
+ * kvm_enter_from_guest_mode - Hook called just after entering kernel from guest.
+ * @vcpu:   Pointer to the current VCPU data
+ */
+void kvm_enter_from_guest_mode(struct kvm_vcpu *vcpu);
+
+/**
+ * kvm_exit_to_guest_mode - Hook called just before entering guest from kernel.
+ * @vcpu:   Pointer to the current VCPU data
+ */
+void kvm_exit_to_guest_mode(struct kvm_vcpu *vcpu);
+
 #endif
diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c
index eb1a8a4c867c..994af4241646 100644
--- a/kernel/entry/kvm.c
+++ b/kernel/entry/kvm.c
@@ -49,3 +49,15 @@ int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu)
 	return xfer_to_guest_mode_work(vcpu, ti_work);
 }
 EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work);
+
+void kvm_enter_from_guest_mode(struct kvm_vcpu *vcpu)
+{
+	sched_core_unsafe_enter();
+}
+EXPORT_SYMBOL_GPL(kvm_enter_from_guest_mode);
+
+void kvm_exit_to_guest_mode(struct kvm_vcpu *vcpu)
+{
+	sched_core_unsafe_exit_wait(XFER_TO_GUEST_MODE_WORK);
+}
+EXPORT_SYMBOL_GPL(kvm_exit_to_guest_mode);
-- 
2.28.0.220.ged08abb693-goog


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-15  3:18 [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Joel Fernandes (Google)
2020-08-15  3:18 ` [PATCH RFC 01/12] irq_work: Add support to detect if work is pending Joel Fernandes (Google)
2020-08-15  8:13   ` peterz
2020-08-17  2:04     ` Joel Fernandes
2020-08-15  3:18 ` [PATCH RFC 02/12] entry/idle: Add a common function for activites during idle entry/exit Joel Fernandes (Google)
2020-08-15  8:14   ` peterz
2020-08-17  2:17     ` Joel Fernandes
2020-08-15  3:18 ` [PATCH RFC 03/12] arch/x86: Add a new TIF flag for untrusted tasks Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 04/12] kernel/entry: Add support for core-wide protection of kernel-mode Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 05/12] entry/idle: Enter and exit kernel protection during idle entry and exit Joel Fernandes (Google)
2020-08-15  3:19 ` Joel Fernandes (Google) [this message]
2020-08-15  3:19 ` [PATCH RFC 07/12] bitops: Introduce find_next_or_bit Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 08/12] cpumask: Introduce a new iterator for_each_cpu_wrap_or Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 09/12] sched/coresched: Use for_each_cpu(_wrap)_or for pick_next_task Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 10/12] sched/coresched: Make core_pick_seq per run-queue Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 11/12] sched/coresched: Check for dynamic changes in smt_mask Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 12/12] sched/coresched: rq->core should be set only if not previously set Joel Fernandes (Google)
2020-08-19 18:26 ` [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Kees Cook
2020-08-20  1:44   ` Joel Fernandes
2020-08-22 20:22 ` Joel Fernandes

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