[PATCH] KVM: PPC:enable mmio_sign_extend in kvmppc_handle_load()

[Bin Lu]

The logic of 'kvmppc_handle_loads' is same as 'kvmppc_handle_load',
but with sign extension.  It sets mmio_sign_extend to 1, then calls
'kvmppc_handle_load', but in 'kvmppc_handle_load', the
mmio_sign_extend flag is reset to 0, so the data does not actually get
sign-extended.

This patch fixes the bug by removing the 'kvmppc_handle_loads'
function, adding a new parameter 'mmio_sign_extend' to
'kvmppc_handle_load'.  Calls to kvmppc_handle_loads() are replaced by
calls to kvmppc_handle_load() with 1 for the sign-extend parameter,
and existing calls to kvmppc_handle_load() have 0 added for the
sign-extend parameter.

Signed-off-by: Bin Lu <lblulb@xxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/include/asm/kvm_ppc.h       |  5 +----
 arch/powerpc/kvm/book3s_paired_singles.c |  6 +++---
 arch/powerpc/kvm/emulate_loadstore.c     | 34 ++++++++++++++++----------------
 arch/powerpc/kvm/powerpc.c               | 17 ++--------------
 4 files changed, 23 insertions(+), 39 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index af353f6..76829fa 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -74,10 +74,7 @@ extern void kvmppc_handler_highmem(void);
 extern void kvmppc_dump_vcpu(struct kvm_vcpu *vcpu);
 extern int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
                               unsigned int rt, unsigned int bytes,
-			      int is_default_endian);
-extern int kvmppc_handle_loads(struct kvm_run *run, struct kvm_vcpu *vcpu,
-                               unsigned int rt, unsigned int bytes,
-			       int is_default_endian);
+			      int is_default_endian, u8 is_sign_extend);
 extern int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			       u64 val, unsigned int bytes,
 			       int is_default_endian);
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index a759d9a..c9e3008 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -200,7 +200,7 @@ static int kvmppc_emulate_fpr_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		goto done_load;
 	} else if (r == EMULATE_DO_MMIO) {
 		emulated = kvmppc_handle_load(run, vcpu, KVM_MMIO_REG_FPR | rs,
-					      len, 1);
+					      len, 1, 0);
 		goto done_load;
 	}
 
@@ -291,12 +291,12 @@ static int kvmppc_emulate_psq_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		goto done_load;
 	} else if ((r == EMULATE_DO_MMIO) && w) {
 		emulated = kvmppc_handle_load(run, vcpu, KVM_MMIO_REG_FPR | rs,
-					      4, 1);
+					      4, 1, 0);
 		vcpu->arch.qpr[rs] = tmp[1];
 		goto done_load;
 	} else if (r == EMULATE_DO_MMIO) {
 		emulated = kvmppc_handle_load(run, vcpu, KVM_MMIO_REG_FQPR | rs,
-					      8, 1);
+					      8, 1, 0);
 		goto done_load;
 	}
 
diff --git a/arch/powerpc/kvm/emulate_loadstore.c b/arch/powerpc/kvm/emulate_loadstore.c
index 6d3c0ee..38b3b6b 100644
--- a/arch/powerpc/kvm/emulate_loadstore.c
+++ b/arch/powerpc/kvm/emulate_loadstore.c
@@ -70,15 +70,15 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 	case 31:
 		switch (get_xop(inst)) {
 		case OP_31_XOP_LWZX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1, 0);
 			break;
 
 		case OP_31_XOP_LBZX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1, 0);
 			break;
 
 		case OP_31_XOP_LBZUX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1, 0);
 			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 			break;
 
@@ -102,15 +102,15 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 			break;
 
 		case OP_31_XOP_LHAX:
-			emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 1);
 			break;
 
 		case OP_31_XOP_LHZX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 0);
 			break;
 
 		case OP_31_XOP_LHZUX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 0);
 			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 			break;
 
@@ -138,7 +138,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 			break;
 
 		case OP_31_XOP_LWBRX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0, 0);
 			break;
 
 		case OP_31_XOP_STWBRX:
@@ -148,7 +148,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 			break;
 
 		case OP_31_XOP_LHBRX:
-			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
+			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0, 0);
 			break;
 
 		case OP_31_XOP_STHBRX:
@@ -164,26 +164,26 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 		break;
 
 	case OP_LWZ:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1, 0);
 		break;
 
 	/* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
 	case OP_LD:
 		rt = get_rt(inst);
-		emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1, 0);
 		break;
 
 	case OP_LWZU:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1, 0);
 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 		break;
 
 	case OP_LBZ:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1, 0);
 		break;
 
 	case OP_LBZU:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1, 0);
 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 		break;
 
@@ -222,20 +222,20 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 		break;
 
 	case OP_LHZ:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 0);
 		break;
 
 	case OP_LHZU:
-		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 0);
 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 		break;
 
 	case OP_LHA:
-		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 1);
 		break;
 
 	case OP_LHAU:
-		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1, 1);
 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 		break;
 
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 99dc554..63f68e6 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -800,7 +800,7 @@ static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu,
 
 int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		       unsigned int rt, unsigned int bytes,
-		       int is_default_endian)
+		       int is_default_endian, u8 is_sign_extend)
 {
 	int idx, ret;
 	bool host_swabbed;
@@ -825,7 +825,7 @@ int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	vcpu->arch.mmio_host_swabbed = host_swabbed;
 	vcpu->mmio_needed = 1;
 	vcpu->mmio_is_write = 0;
-	vcpu->arch.mmio_sign_extend = 0;
+	vcpu->arch.mmio_sign_extend = is_sign_extend;
 
 	idx = srcu_read_lock(&vcpu->kvm->srcu);
 
@@ -844,19 +844,6 @@ int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 }
 EXPORT_SYMBOL_GPL(kvmppc_handle_load);
 
-/* 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_default_endian)
-{
-	int r;
-
-	vcpu->arch.mmio_sign_extend = 1;
-	r = kvmppc_handle_load(run, vcpu, rt, bytes, is_default_endian);
-
-	return r;
-}
-
 int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			u64 val, unsigned int bytes, int is_default_endian)
 {
-- 
2.4.0