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    Subject[PATCH 3.12 61/63] arm64: KVM: Fix HCR setting for 32bit guests
    Date
    From: Marc Zyngier <marc.zyngier@arm.com>

    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@arm.com>
    Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
    Signed-off-by: Jiri Slaby <jslaby@suse.cz>
    ---
    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;
    }
    --
    2.3.5


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