From f19d1f367a506bc645f8d6695942b8873fc82c84 Mon Sep 17 00:00:00 2001
From: Simon Guo <wei.guo.simon@gmail.com>
Date: Mon, 7 May 2018 14:20:09 +0800
Subject: [PATCH] KVM: PPC: Fix a mmio_host_swabbed uninitialized usage issue
References: bsc#1061840
Patch-mainline: v4.18-rc1
Git-commit: f19d1f367a506bc645f8d6695942b8873fc82c84
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 <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kvm/emulate_loadstore.c | 1 +
arch/powerpc/kvm/powerpc.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/emulate_loadstore.c b/arch/powerpc/kvm/emulate_loadstore.c
index a382e15135e6..b8a3aefc3033 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 4e387647b5af..bef27b16d233 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];
--
2.13.7