[PATCH 14/16] riscv: kvm: Use generated instruction headers for csr emulation

[Charlie Jenkins via B4 Relay]

From: Charlie Jenkins <thecharlesjenkins@xxxxxxxxx>

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

Signed-off-by: Charlie Jenkins <thecharlesjenkins@xxxxxxxxx>

---
This can be tested with the introduced csr_test selftest.
---
 arch/riscv/include/asm/kvm_vcpu_insn.h |  3 +-
 arch/riscv/kvm/vcpu_insn.c             | 61 +++++++++++++++++-----------------
 2 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_insn.h b/arch/riscv/include/asm/kvm_vcpu_insn.h
index 106fb4c45108..01efdaaede21 100644
--- a/arch/riscv/include/asm/kvm_vcpu_insn.h
+++ b/arch/riscv/include/asm/kvm_vcpu_insn.h
@@ -19,7 +19,8 @@ struct kvm_mmio_decode {
 };
 
 struct kvm_csr_decode {
-	unsigned long insn;
+	unsigned long rd;
+	unsigned long insn_len;
 	int return_handled;
 };
 
diff --git a/arch/riscv/kvm/vcpu_insn.c b/arch/riscv/kvm/vcpu_insn.c
index c5a70de4a579..d666cd24f8c0 100644
--- a/arch/riscv/kvm/vcpu_insn.c
+++ b/arch/riscv/kvm/vcpu_insn.c
@@ -13,8 +13,7 @@
 #include <asm/kvm_vcpu_test_csr.h>
 
 struct insn_func {
-	unsigned long mask;
-	unsigned long match;
+	bool (*cmp)(u32 insn);
 	/*
 	 * Possible return values are as follows:
 	 * 1) Returns < 0 for error case
@@ -131,20 +130,17 @@ static const struct csr_func csr_funcs[] = {
  */
 int kvm_riscv_vcpu_csr_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
-	ulong insn;
-
 	if (vcpu->arch.csr_decode.return_handled)
 		return 0;
 	vcpu->arch.csr_decode.return_handled = 1;
 
 	/* Update destination register for CSR reads */
-	insn = vcpu->arch.csr_decode.insn;
-	if ((insn >> SH_RD) & MASK_RX)
-		SET_RD(insn, &vcpu->arch.guest_context,
-		       run->riscv_csr.ret_value);
+	if (vcpu->arch.csr_decode.rd)
+		*((ulong *)&vcpu->arch.guest_context +
+		  vcpu->arch.csr_decode.rd) = run->riscv_csr.ret_value;
 
 	/* Move to next instruction */
-	vcpu->arch.guest_context.sepc += INSN_LEN(insn);
+	vcpu->arch.guest_context.sepc += vcpu->arch.csr_decode.insn_len;
 
 	return 0;
 }
@@ -154,7 +150,7 @@ static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 	#define GET_REG(_rd) (*((unsigned long *)(&vcpu->arch.guest_context) + _rd))
 
 	int i, rc = KVM_INSN_ILLEGAL_TRAP;
-	unsigned int csr_num;
+	unsigned int csr_num, rd;
 	const struct csr_func *tcfn, *cfn = NULL;
 	ulong val = 0, wr_mask = 0, new_val = 0;
 
@@ -163,26 +159,32 @@ static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 		wr_mask = -1UL;
 		new_val = GET_REG(riscv_insn_csrrw_extract_xs1(insn));
 		csr_num = riscv_insn_csrrw_extract_csr(insn);
+		rd = riscv_insn_csrrw_extract_xd(insn);
 	} else if (riscv_insn_is_csrrs(insn)) {
 		wr_mask = GET_REG(riscv_insn_csrrs_extract_xs1(insn));
 		new_val = -1UL;
 		csr_num = riscv_insn_csrrs_extract_csr(insn);
+		rd = riscv_insn_csrrs_extract_xd(insn);
 	} else if (riscv_insn_is_csrrc(insn)) {
-		wr_mask = GET_REG(riscv_insn_csrrs_extract_xs1(insn));
+		wr_mask = GET_REG(riscv_insn_csrrc_extract_xs1(insn));
 		new_val = 0;
 		csr_num = riscv_insn_csrrc_extract_csr(insn);
+		rd = riscv_insn_csrrc_extract_xd(insn);
 	} else if (riscv_insn_is_csrrwi(insn)) {
 		wr_mask = -1UL;
 		new_val = riscv_insn_csrrwi_extract_imm(insn);
 		csr_num = riscv_insn_csrrwi_extract_csr(insn);
+		rd = riscv_insn_csrrwi_extract_xd(insn);
 	} else if (riscv_insn_is_csrrsi(insn)) {
 		wr_mask = riscv_insn_csrrwi_extract_imm(insn);
 		new_val = -1UL;
 		csr_num = riscv_insn_csrrsi_extract_csr(insn);
+		rd = riscv_insn_csrrsi_extract_xd(insn);
 	} else if (riscv_insn_is_csrrci(insn)) {
-		wr_mask = GET_REG(riscv_insn_csrrwi_extract_imm(insn));
+		wr_mask = riscv_insn_csrrci_extract_imm(insn);
 		new_val = 0;
-		csr_num = riscv_insn_csrrwi_extract_csr(insn);
+		csr_num = riscv_insn_csrrci_extract_csr(insn);
+		rd = riscv_insn_csrrci_extract_xd(insn);
 	} else {
 		return rc;
 	}
@@ -190,7 +192,8 @@ static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 	#undef GET_REG
 
 	/* Save instruction decode info */
-	vcpu->arch.csr_decode.insn = insn;
+	vcpu->arch.csr_decode.rd = rd;
+	vcpu->arch.csr_decode.insn_len = INSN_LEN(insn);
 	vcpu->arch.csr_decode.return_handled = 0;
 
 	/* Update CSR details in kvm_run struct */
@@ -234,43 +237,39 @@ static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 
 static const struct insn_func system_opcode_funcs[] = {
 	{
-		.mask  = INSN_MASK_CSRRW,
-		.match = INSN_MATCH_CSRRW,
+		.cmp  = riscv_insn_is_csrrw,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_CSRRS,
-		.match = INSN_MATCH_CSRRS,
+		.cmp  = riscv_insn_is_csrrs,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_CSRRC,
-		.match = INSN_MATCH_CSRRC,
+		.cmp  = riscv_insn_is_csrrc,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_CSRRWI,
-		.match = INSN_MATCH_CSRRWI,
+		.cmp  = riscv_insn_is_csrrwi,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_CSRRSI,
-		.match = INSN_MATCH_CSRRSI,
+		.cmp  = riscv_insn_is_csrrsi,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_CSRRCI,
-		.match = INSN_MATCH_CSRRCI,
+		.cmp  = riscv_insn_is_csrrci,
 		.func  = csr_insn,
 	},
 	{
-		.mask  = INSN_MASK_WFI,
-		.match = INSN_MATCH_WFI,
+		.cmp  = riscv_insn_is_wfi,
 		.func  = wfi_insn,
 	},
 	{
-		.mask  = INSN_MASK_WRS,
-		.match = INSN_MATCH_WRS,
+		.cmp  = riscv_insn_is_wrs_nto,
+		.func  = wrs_insn,
+	},
+	{
+		.cmp  = riscv_insn_is_wrs_sto,
 		.func  = wrs_insn,
 	},
 };
@@ -283,7 +282,7 @@ static int system_opcode_insn(struct kvm_vcpu *vcpu, struct kvm_run *run,
 
 	for (i = 0; i < ARRAY_SIZE(system_opcode_funcs); i++) {
 		ifn = &system_opcode_funcs[i];
-		if ((insn & ifn->mask) == ifn->match) {
+		if (ifn->cmp(insn)) {
 			rc = ifn->func(vcpu, run, insn);
 			break;
 		}

-- 
2.52.0