KVM: PPC: Teach MMIO Signedness
The guest I was trying to get to run uses the LHA and LHAU instructions.
Those instructions basically do a load, but also sign extend the result.
Since we need to fill our registers by hand when doing MMIO, we also need
to sign extend manually.
This patch implements sign extended MMIO and the LHA(U) instructions.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index fb87dcf..119deb4 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -270,6 +270,7 @@
u8 io_gpr; /* GPR used as IO source/target */
u8 mmio_is_bigendian;
+ u8 mmio_sign_extend;
u8 dcr_needed;
u8 dcr_is_write;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index c011170..a288dd2 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -48,6 +48,9 @@
extern int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int rt, unsigned int bytes,
int is_bigendian);
+extern int kvmppc_handle_loads(struct kvm_run *run, struct kvm_vcpu *vcpu,
+ unsigned int rt, unsigned int bytes,
+ int is_bigendian);
extern int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
u64 val, unsigned int bytes, int is_bigendian);
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index cb72a65..11789dd 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -62,6 +62,8 @@
#define OP_STBU 39
#define OP_LHZ 40
#define OP_LHZU 41
+#define OP_LHA 42
+#define OP_LHAU 43
#define OP_STH 44
#define OP_STHU 45
@@ -450,6 +452,18 @@
kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
break;
+ case OP_LHA:
+ rt = get_rt(inst);
+ emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+ break;
+
+ case OP_LHAU:
+ ra = get_ra(inst);
+ rt = get_rt(inst);
+ emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+ kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
+ break;
+
case OP_STH:
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu,
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b7858b1..1266ed0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -301,6 +301,22 @@
}
}
+ if (vcpu->arch.mmio_sign_extend) {
+ switch (run->mmio.len) {
+#ifdef CONFIG_PPC64
+ case 4:
+ gpr = (s64)(s32)gpr;
+ break;
+#endif
+ case 2:
+ gpr = (s64)(s16)gpr;
+ break;
+ case 1:
+ gpr = (s64)(s8)gpr;
+ break;
+ }
+ }
+
kvmppc_set_gpr(vcpu, vcpu->arch.io_gpr, gpr);
switch (vcpu->arch.io_gpr & KVM_REG_EXT_MASK) {
@@ -338,10 +354,23 @@
vcpu->arch.mmio_is_bigendian = is_bigendian;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 0;
+ vcpu->arch.mmio_sign_extend = 0;
return EMULATE_DO_MMIO;
}
+/* Same as above, but sign extends */
+int kvmppc_handle_loads(struct kvm_run *run, struct kvm_vcpu *vcpu,
+ unsigned int rt, unsigned int bytes, int is_bigendian)
+{
+ int r;
+
+ r = kvmppc_handle_load(run, vcpu, rt, bytes, is_bigendian);
+ vcpu->arch.mmio_sign_extend = 1;
+
+ return r;
+}
+
int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
u64 val, unsigned int bytes, int is_bigendian)
{