linux-kernel - [PATCH v2 21/29] LoongArch: KVM: Implement handle iocsr exception

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Date:   Mon, 20 Feb 2023 14:57:27 +0800
From:   Tianrui Zhao <zhaotianrui@...ngson.cn>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
        Mark Brown <broonie@...nel.org>,
        Alex Deucher <alexander.deucher@....com>,
        Oliver Upton <oliver.upton@...ux.dev>, maobibo@...ngson.cn
Subject: [PATCH v2 21/29] LoongArch: KVM: Implement handle iocsr exception

Implement kvm handle vcpu iocsr exception, setting the iocsr info into
vcpu_run and return to user space to handle it.

Signed-off-by: Tianrui Zhao <zhaotianrui@...ngson.cn>
---
 arch/loongarch/include/asm/inst.h | 16 ++++++
 arch/loongarch/kvm/exit.c         | 92 +++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)

diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index 7eedd83fd..8ed137814 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -50,6 +50,14 @@ enum reg2_op {
 	revbd_op	= 0x0f,
 	revh2w_op	= 0x10,
 	revhd_op	= 0x11,
+	iocsrrdb_op	= 0x19200,
+	iocsrrdh_op	= 0x19201,
+	iocsrrdw_op	= 0x19202,
+	iocsrrdd_op	= 0x19203,
+	iocsrwrb_op	= 0x19204,
+	iocsrwrh_op	= 0x19205,
+	iocsrwrw_op	= 0x19206,
+	iocsrwrd_op	= 0x19207,
 };
 
 enum reg2i5_op {
@@ -261,6 +269,13 @@ struct reg3sa2_format {
 	unsigned int opcode : 15;
 };
 
+struct reg2csr_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int csr : 14;
+	unsigned int opcode : 8;
+};
+
 union loongarch_instruction {
 	unsigned int word;
 	struct reg0i26_format	reg0i26_format;
@@ -275,6 +290,7 @@ union loongarch_instruction {
 	struct reg2bstrd_format	reg2bstrd_format;
 	struct reg3_format	reg3_format;
 	struct reg3sa2_format	reg3sa2_format;
+	struct reg2csr_format	reg2csr_format;
 };
 
 #define LOONGARCH_INSN_SIZE	sizeof(union loongarch_instruction)
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index dc37827d9..f02e2b940 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -99,3 +99,95 @@ static int _kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst)
 
 	return EMULATE_DONE;
 }
+
+int _kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+	u32 rd, rj, opcode;
+	u32 addr;
+	unsigned long val;
+	int ret;
+
+	/*
+	 * Each IOCSR with different opcode
+	 */
+	rd = inst.reg2_format.rd;
+	rj = inst.reg2_format.rj;
+	opcode = inst.reg2_format.opcode;
+	addr = vcpu->arch.gprs[rj];
+	ret = EMULATE_DO_IOCSR;
+	run->iocsr_io.phys_addr = addr;
+	run->iocsr_io.is_write = 0;
+
+	/* LoongArch is Little endian */
+	switch (opcode) {
+	case iocsrrdb_op:
+		run->iocsr_io.len = 1;
+		break;
+	case iocsrrdh_op:
+		run->iocsr_io.len = 2;
+		break;
+	case iocsrrdw_op:
+		run->iocsr_io.len = 4;
+		break;
+	case iocsrrdd_op:
+		run->iocsr_io.len = 8;
+		break;
+	case iocsrwrb_op:
+		run->iocsr_io.len = 1;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrh_op:
+		run->iocsr_io.len = 2;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrw_op:
+		run->iocsr_io.len = 4;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrd_op:
+		run->iocsr_io.len = 8;
+		run->iocsr_io.is_write = 1;
+		break;
+	default:
+		ret = EMULATE_FAIL;
+		break;
+	}
+
+	if (ret == EMULATE_DO_IOCSR) {
+		if (run->iocsr_io.is_write) {
+			val = vcpu->arch.gprs[rd];
+			memcpy(run->iocsr_io.data, &val, run->iocsr_io.len);
+		}
+		vcpu->arch.io_gpr = rd;
+	}
+
+	return ret;
+}
+
+int _kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
+	enum emulation_result er = EMULATE_DONE;
+
+	switch (run->iocsr_io.len) {
+	case 8:
+		*gpr = *(s64 *)run->iocsr_io.data;
+		break;
+	case 4:
+		*gpr = *(int *)run->iocsr_io.data;
+		break;
+	case 2:
+		*gpr = *(short *)run->iocsr_io.data;
+		break;
+	case 1:
+		*gpr = *(char *) run->iocsr_io.data;
+		break;
+	default:
+		kvm_err("Bad IOCSR length: %d,addr is 0x%lx",
+				run->iocsr_io.len, vcpu->arch.badv);
+		er = EMULATE_FAIL;
+		break;
+	}
+
+	return er;
+}
-- 
2.31.1