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authorJames Hogan <james.hogan@imgtec.com>2016-07-08 11:53:28 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2016-08-01 18:42:25 +0200
commit172e02d1474d5c37a8728ccdfdc731c118366144 (patch)
tree5aa672f62fde25a0eaedcdbca40b9db3001f877c /arch
parent5808844f03b4b31a13a87cf41cc0701718c1b622 (diff)
MIPS: KVM: Sign extend MFC0/RDHWR results
When emulating MFC0 instructions to load 32-bit values from guest COP0 registers and the RDHWR instruction to read the CC (Count) register, sign extend the result to comply with the MIPS64 architecture. The result must be in canonical 32-bit form or the guest may malfunction. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/kvm/emulate.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index be18dfe9ecaa..6eb52b9c9818 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1072,14 +1072,15 @@ enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst,
#endif
/* Get reg */
if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
- vcpu->arch.gprs[rt] = kvm_mips_read_count(vcpu);
+ vcpu->arch.gprs[rt] =
+ (s32)kvm_mips_read_count(vcpu);
} else if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
vcpu->arch.gprs[rt] = 0x0;
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mfc0(inst, opc, vcpu);
#endif
} else {
- vcpu->arch.gprs[rt] = cop0->reg[rd][sel];
+ vcpu->arch.gprs[rt] = (s32)cop0->reg[rd][sel];
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mfc0(inst, opc, vcpu);
@@ -2380,7 +2381,7 @@ enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc,
current_cpu_data.icache.linesz);
break;
case MIPS_HWR_CC: /* Read count register */
- arch->gprs[rt] = kvm_mips_read_count(vcpu);
+ arch->gprs[rt] = (s32)kvm_mips_read_count(vcpu);
break;
case MIPS_HWR_CCRES: /* Count register resolution */
switch (current_cpu_data.cputype) {