[PATCH v3 09/17] riscv: kvm: Use generated instruction headers for csr code

[Charlie Jenkins]

Migrate the csr parsing code to use the generated instruction headers
instead of the hand-written instruction composition functions.

Signed-off-by: Charlie Jenkins <thecharlesjenkins at gmail.com>

---

This is a simple transformation that I have again validated through
brute force.
---
 arch/riscv/kvm/vcpu_insn.c | 50 +++++++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 23 deletions(-)

diff --git a/arch/riscv/kvm/vcpu_insn.c b/arch/riscv/kvm/vcpu_insn.c
index f09f9251d1f0..a1898ab8bbe8 100644
--- a/arch/riscv/kvm/vcpu_insn.c
+++ b/arch/riscv/kvm/vcpu_insn.c
@@ -144,45 +144,49 @@ int kvm_riscv_vcpu_csr_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	return 0;
 }
 
+static inline unsigned long get_reg(struct kvm_cpu_context *context, unsigned int rd)
+{
+	return *((unsigned long *)(context) + rd);
+}
+
 static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 {
 	int i, rc = KVM_INSN_ILLEGAL_TRAP;
-	unsigned int csr_num = insn >> SH_RS2;
-	unsigned int rs1_num = (insn >> SH_RS1) & MASK_RX;
-	ulong rs1_val = GET_RS1(insn, &vcpu->arch.guest_context);
+	unsigned int csr_num;
 	const struct csr_func *tcfn, *cfn = NULL;
 	ulong val = 0, wr_mask = 0, new_val = 0;
 
 	/* Decode the CSR instruction */
-	switch (GET_FUNCT3(insn)) {
-	case GET_FUNCT3(INSN_MATCH_CSRRW):
+	if (riscv_insn_is_csrrw(insn)) {
 		wr_mask = -1UL;
-		new_val = rs1_val;
-		break;
-	case GET_FUNCT3(INSN_MATCH_CSRRS):
-		wr_mask = rs1_val;
+		new_val = get_reg(&vcpu->arch.guest_context, riscv_insn_csrrw_extract_xs1(insn));
+		csr_num = riscv_insn_csrrw_extract_csr(insn);
+	} else if (riscv_insn_is_csrrs(insn)) {
+		wr_mask = get_reg(&vcpu->arch.guest_context, riscv_insn_csrrs_extract_xs1(insn));
 		new_val = -1UL;
-		break;
-	case GET_FUNCT3(INSN_MATCH_CSRRC):
-		wr_mask = rs1_val;
+		csr_num = riscv_insn_csrrs_extract_csr(insn);
+	} else if (riscv_insn_is_csrrc(insn)) {
+		wr_mask = get_reg(&vcpu->arch.guest_context, riscv_insn_csrrc_extract_xs1(insn));
 		new_val = 0;
-		break;
-	case GET_FUNCT3(INSN_MATCH_CSRRWI):
+		csr_num = riscv_insn_csrrc_extract_csr(insn);
+	} else if (riscv_insn_is_csrrwi(insn)) {
 		wr_mask = -1UL;
-		new_val = rs1_num;
-		break;
-	case GET_FUNCT3(INSN_MATCH_CSRRSI):
-		wr_mask = rs1_num;
+		new_val = riscv_insn_csrrwi_extract_imm(insn);
+		csr_num = riscv_insn_csrrwi_extract_csr(insn);
+	} else if (riscv_insn_is_csrrsi(insn)) {
+		wr_mask = riscv_insn_csrrwi_extract_imm(insn);
 		new_val = -1UL;
-		break;
-	case GET_FUNCT3(INSN_MATCH_CSRRCI):
-		wr_mask = rs1_num;
+		csr_num = riscv_insn_csrrsi_extract_csr(insn);
+	} else if (riscv_insn_is_csrrci(insn)) {
+		wr_mask = GET_REG(riscv_insn_csrrwi_extract_imm(insn));
 		new_val = 0;
-		break;
-	default:
+		csr_num = riscv_insn_csrrwi_extract_csr(insn);
+	} else {
 		return rc;
 	}
 
+	#undef GET_REG
+
 	/* Save instruction decode info */
 	vcpu->arch.csr_decode.insn = insn;
 	vcpu->arch.csr_decode.return_handled = 0;

-- 
2.54.0