[PATCH 3.12 61/63] arm64: KVM: Fix HCR setting for 32bit guests

From: Jiri Slaby
Date: Thu Apr 30 2015 - 08:16:22 EST

From: Marc Zyngier <marc.zyngier@xxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


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.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
arch/arm64/include/asm/kvm_emulate.h | 2 ++
arch/arm64/kvm/reset.c | 1 -
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 45d8633d746e..2b01e2bdb7ef 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -41,6 +41,8 @@ void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
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)
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 70a7816535cd..0b4326578985 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -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;

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