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Subject[PATCH] kvm: disable stealtime via reboot notifier to avoid mem corruption
Date
else, we get memory corruption on reboot; found when tracking down
initramfs unpack error on initial reboot (with qemu-kvm -smp 2,
no problem with single-core).

problem with doing it via kvm_shutdown() is that this file
depends on CONFIG_KVM_CLOCK, also its not enough to call it for one
cpu only.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
not subscribed, please CC on replies.
Also, I don't know much about kvm or kexec, so its possible
that i missed something.

In any case, this seems to fix the initramfs corruption for me.
patch is against virt/kvm/kvm.git.

arch/x86/kernel/kvm.c | 1 +
arch/x86/kernel/kvmclock.c | 1 -
2 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index c1d61ee..1596cc8 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -354,6 +354,7 @@ static void kvm_pv_guest_cpu_reboot(void *unused)
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
wrmsrl(MSR_KVM_PV_EOI_EN, 0);
kvm_pv_disable_apf();
+ kvm_disable_steal_time();
}

static int kvm_pv_reboot_notify(struct notifier_block *nb,
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index f1b42b3..5a2fa7d 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -191,7 +191,6 @@ static void kvm_crash_shutdown(struct pt_regs *regs)
static void kvm_shutdown(void)
{
native_write_msr(msr_kvm_system_time, 0, 0);
- kvm_disable_steal_time();
native_machine_shutdown();
}

--
1.7.8.6


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