[3.16.y-ckt stable] Patch "arm/arm64: kvm: drop inappropriate use of kvm_is_mmio_pfn()" has been added to staging queue

[Luis Henriques]

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

    arm/arm64: kvm: drop inappropriate use of kvm_is_mmio_pfn()

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-ckt12.

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

------

>From 8cd08171f09ddf116f9d9bfa56678cb5a52f2a6f Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Date: Mon, 10 Nov 2014 08:33:55 +0000
Subject: arm/arm64: kvm: drop inappropriate use of kvm_is_mmio_pfn()

commit 07a9748c78cfc39b54f06125a216b67b9c8f09ed upstream.

Instead of using kvm_is_mmio_pfn() to decide whether a host region
should be stage 2 mapped with device attributes, add a new static
function kvm_is_device_pfn() that disregards RAM pages with the
reserved bit set, as those should usually not be mapped as device
memory.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm/kvm/mmu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 222e59918d28..8cfb491776a9 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -755,6 +755,11 @@ static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
 	return kvm_vcpu_dabt_iswrite(vcpu);
 }

+static bool kvm_is_device_pfn(unsigned long pfn)
+{
+	return !pfn_valid(pfn);
+}
+
 static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			  struct kvm_memory_slot *memslot,
 			  unsigned long fault_status)
@@ -825,7 +830,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (is_error_pfn(pfn))
 		return -EFAULT;

-	if (kvm_is_mmio_pfn(pfn))
+	if (kvm_is_device_pfn(pfn))
 		mem_type = PAGE_S2_DEVICE;

 	spin_lock(&kvm->mmu_lock);