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From: AKASHI Takahiro <takahiro.akashi@linaro.org>
To: catalin.marinas@arm.com, will.deacon@arm.com,
	marc.zyngier@arm.com, mark.rutland@arm.com
Cc: christoffer.dall@linaro.org, geoff@infradead.org,
	broonie@kernel.org, david.griego@linaro.org, freddy77@gmail.com,
	kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
	linaro-kernel@lists.linaro.org, linux-kernel@vger.kernel.org,
	AKASHI Takahiro <takahiro.akashi@linaro.org>
Subject: [v3 2/5] arm64: kvm: allow EL2 context to be reset on shutdown
Date: Thu,  2 Apr 2015 14:40:13 +0900	[thread overview]
Message-ID: <1427953216-11737-3-git-send-email-takahiro.akashi@linaro.org> (raw)
In-Reply-To: <1427953216-11737-1-git-send-email-takahiro.akashi@linaro.org>

The current kvm implementation keeps EL2 vector table installed even
when the system is shut down. This prevents kexec from putting the system
with kvm back into EL2 when starting a new kernel.

This patch resolves this issue by calling a cpu tear-down function via
reboot notifier, kvm_reboot_notify(), which is invoked by
kernel_restart_prepare() in kernel_kexec().
While kvm has a generic hook, kvm_reboot(), we can't use it here because
a cpu teardown function will not be invoked, under current implementation,
if no guest vm has been created by kvm_create_vm().
Please note that kvm_usage_count is zero in this case.

We'd better, in the future, implement cpu hotplug support and put the
arch-specific initialization into kvm_arch_hardware_enable/disable().
This way, we would be able to revert this patch.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm/kvm/arm.c     |   21 +++++++++++++++++++++
 arch/arm64/kvm/Kconfig |    1 -
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 39df694..f64713e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -25,6 +25,7 @@
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/mman.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/kvm.h>
 #include <trace/events/kvm.h>
@@ -1100,6 +1101,23 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
 	return NULL;
 }
 
+static int kvm_reboot_notify(struct notifier_block *nb,
+			     unsigned long val, void *v)
+{
+	/*
+	 * Reset each CPU in EL2 to initial state.
+	 */
+	on_each_cpu(kvm_cpu_reset, NULL, 1);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block kvm_reboot_nb = {
+	.notifier_call		= kvm_reboot_notify,
+	.next			= NULL,
+	.priority		= 0, /* FIXME */
+};
+
 /**
  * Initialize Hyp-mode and memory mappings on all CPUs.
  */
@@ -1138,6 +1156,9 @@ int kvm_arch_init(void *opaque)
 	hyp_cpu_pm_init();
 
 	kvm_coproc_table_init();
+
+	register_reboot_notifier(&kvm_reboot_nb);
+
 	return 0;
 out_err:
 	cpu_notifier_register_done();
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 30ae7a7..f5590c8 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -18,7 +18,6 @@ if VIRTUALIZATION
 
 config KVM
 	bool "Kernel-based Virtual Machine (KVM) support"
-	depends on !KEXEC
 	select MMU_NOTIFIER
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
-- 
1.7.9.5


  parent reply	other threads:[~2015-04-02  5:41 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-02  5:40 [v3 0/5] arm64: kvm: reset hyp context for kexec AKASHI Takahiro
2015-04-02  5:40 ` [v3 1/5] arm64: kvm: add a cpu tear-down function AKASHI Takahiro
2015-04-08 13:02   ` Mark Rutland
2015-04-09  3:53     ` AKASHI Takahiro
2015-04-02  5:40 ` AKASHI Takahiro [this message]
2015-04-08 13:05   ` [v3 2/5] arm64: kvm: allow EL2 context to be reset on shutdown Mark Rutland
2015-04-09  4:53     ` AKASHI Takahiro
2015-04-09 15:02       ` Mark Rutland
2015-04-10  6:15         ` AKASHI Takahiro
2015-04-15 12:49           ` Mark Rutland
2015-04-02  5:40 ` [v3 3/5] arm64: kvm: add cpu reset hook for cpu hotplug AKASHI Takahiro
2015-04-02  5:40 ` [v3 4/5] arm64: kvm: add cpu reset at module exit AKASHI Takahiro
2015-04-02  5:40 ` [v3 5/5] arm: kvm: add stub implementation for kvm_cpu_reset() AKASHI Takahiro

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