[3.16.y-ckt stable] Patch "arm64: KVM: Fix host crash when injecting a fault into a 32bit guest" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Thu Sep 3 10:38:01 UTC 2015


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

    arm64: KVM: Fix host crash when injecting a fault into a 32bit guest

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-ckt17.

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 44df150fa22d2210358f3179fd222a9b8a2beb40 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier at arm.com>
Date: Thu, 27 Aug 2015 16:10:01 +0100
Subject: arm64: KVM: Fix host crash when injecting a fault into a 32bit guest

commit 126c69a0bd0e441bf6766a5d9bf20de011be9f68 upstream.

When injecting a fault into a misbehaving 32bit guest, it seems
rather idiotic to also inject a 64bit fault that is only going
to corrupt the guest state. This leads to a situation where we
perform an illegal exception return at EL2 causing the host
to crash instead of killing the guest.

Just fix the stupid bug that has been there from day 1.

Reported-by: Russell King <rmk+kernel at arm.linux.org.uk>
Tested-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm64/kvm/inject_fault.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 81a02a8762b0..86825f8883de 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -168,8 +168,8 @@ void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
 {
 	if (!(vcpu->arch.hcr_el2 & HCR_RW))
 		inject_abt32(vcpu, false, addr);
-
-	inject_abt64(vcpu, false, addr);
+	else
+		inject_abt64(vcpu, false, addr);
 }

 /**
@@ -184,8 +184,8 @@ void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
 {
 	if (!(vcpu->arch.hcr_el2 & HCR_RW))
 		inject_abt32(vcpu, true, addr);
-
-	inject_abt64(vcpu, true, addr);
+	else
+		inject_abt64(vcpu, true, addr);
 }

 /**
@@ -198,6 +198,6 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 {
 	if (!(vcpu->arch.hcr_el2 & HCR_RW))
 		inject_undef32(vcpu);
-
-	inject_undef64(vcpu);
+	else
+		inject_undef64(vcpu);
 }




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