From: Simon Guo Date: Mon, 7 May 2018 06:20:09 +0000 (+0800) Subject: KVM: PPC: Fix a mmio_host_swabbed uninitialized usage issue X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f19d1f367a506bc645f8d6695942b8873fc82c84;p=linux.git KVM: PPC: Fix a mmio_host_swabbed uninitialized usage issue When KVM emulates VMX store, it will invoke kvmppc_get_vmx_data() to retrieve VMX reg val. kvmppc_get_vmx_data() will check mmio_host_swabbed to decide which double word of vr[] to be used. But the mmio_host_swabbed can be uninitialized during VMX store procedure: kvmppc_emulate_loadstore \- kvmppc_handle_store128_by2x64 \- kvmppc_get_vmx_data So vcpu->arch.mmio_host_swabbed is not meant to be used at all for emulation of store instructions, and this patch makes that true for VMX stores. This patch also initializes mmio_host_swabbed to avoid possible future problems. Signed-off-by: Simon Guo Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kvm/emulate_loadstore.c b/arch/powerpc/kvm/emulate_loadstore.c index a382e15135e6d..b8a3aefc30338 100644 --- a/arch/powerpc/kvm/emulate_loadstore.c +++ b/arch/powerpc/kvm/emulate_loadstore.c @@ -111,6 +111,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu) vcpu->arch.mmio_sp64_extend = 0; vcpu->arch.mmio_sign_extend = 0; vcpu->arch.mmio_vmx_copy_nums = 0; + vcpu->arch.mmio_host_swabbed = 0; switch (get_op(inst)) { case 31: diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 4e387647b5af0..bef27b16d2337 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -1374,7 +1374,7 @@ static inline int kvmppc_get_vmx_data(struct kvm_vcpu *vcpu, int rs, u64 *val) if (di > 1) return -1; - if (vcpu->arch.mmio_host_swabbed) + if (kvmppc_need_byteswap(vcpu)) di = 1 - di; w0 = vrs.u[di * 2];