Patch "arm64: KVM: Fix HCR setting for 32bit guests" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

arm64: KVM: Fix HCR setting for 32bit guests

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-kvm-fix-hcr-setting-for-32bit-guests.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Marc Zyngier <[email protected]>
Date: Sun, 11 Jan 2015 14:10:11 +0100
Subject: arm64: KVM: Fix HCR setting for 32bit guests

From: Marc Zyngier <[email protected]>

commit 801f6772cecea6cfc7da61aa197716ab64db5f9e upstream.

Commit b856a59141b1 (arm/arm64: KVM: Reset the HCR on each vcpu when resetting the vcpu) moved the init of the HCR register to happen later in the init of a vcpu, but left out the fixup done in kvm_reset_vcpu when preparing for a 32bit guest.

As a result, the 32bit guest is run as a 64bit guest, but the rest of the kernel still manages it as a 32bit. Fun follows.

Moving the fixup to vcpu_reset_hcr solves the problem for good.

---
 arch/arm64/include/asm/kvm_emulate.h |    2 ++
 arch/arm64/kvm/reset.c               |    1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

@@ -41,6 +41,8 @@ void kvm_inject_pabt(struct kvm_vcpu *vc
 static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
+	if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
+		vcpu->arch.hcr_el2 &= ~HCR_RW;
 }
 
 static inline unsigned long *vcpu_pc(const struct kvm_vcpu *vcpu)

@@ -90,7 +90,6 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu
 			if (!cpu_has_32bit_el1())
 				return -EINVAL;
 			cpu_reset = &default_regs_reset32;
-			vcpu->arch.hcr_el2 &= ~HCR_RW;
 		} else {
 			cpu_reset = &default_regs_reset;
 		}

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/arm64-kvm-fix-hcr-setting-for-32bit-guests.patch queue-3.14/arm64-kvm-do-not-use-pgd_index-to-index-stage-2-pgd.patch queue-3.14/arm64-kvm-fix-tlb-invalidation-by-ipa-vmid.patch queue-3.14/arm-arm64-kvm-keep-elrsr-aisr-in-sync-with-software-model.patch queue-3.14/arm-arm64-kvm-require-in-kernel-vgic-for-the-arch-timers.patch queue-3.14/arm-kvm-force-execution-of-hcptr-access-on-vm-exit.patch