[3.16.y-ckt stable] Patch "arm/arm64: KVM: Fix ioctl error handling" has been added to the 3.16.y-ckt tree

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    arm/arm64: KVM: Fix ioctl error handling

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt26.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From 376612d9cc7be610d26d12285c0405908c847434 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Sun, 28 Feb 2016 17:32:07 +0200
Subject: arm/arm64: KVM: Fix ioctl error handling

commit 4cad67fca3fc952d6f2ed9e799621f07666a560f upstream.

Calling return copy_to_user(...) in an ioctl will not
do the right thing if there's a pagefault:
copy_to_user returns the number of bytes not copied
in this case.

Fix up kvm to do
	return copy_to_user(...)) ?  -EFAULT : 0;

everywhere.

Acked-by: Christoffer Dall <christoffer.dall at linaro.org>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
[ luis: backported to 3.16:
  - dropped changes to arch/arm64/kvm/guest.c ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm/kvm/guest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
index 2786eae10c0d..f3f6415b7828 100644
--- a/arch/arm/kvm/guest.c
+++ b/arch/arm/kvm/guest.c
@@ -183,7 +183,7 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	u64 val;

 	val = kvm_arm_timer_get_reg(vcpu, reg->id);
-	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id));
+	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
 }

 static unsigned long num_core_regs(void)