[PATCH v6 09/30] LoongArch: KVM: Implement vcpu get, vcpu set registers

[Tianrui Zhao]

Implement loongarch vcpu get registers and set registers operations, it
is called when user space use the ioctl interface to get or set regs.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
 arch/loongarch/kvm/csr_ops.S |  76 +++++++++++++
 arch/loongarch/kvm/vcpu.c    | 206 +++++++++++++++++++++++++++++++++++
 2 files changed, 282 insertions(+)
 create mode 100644 arch/loongarch/kvm/csr_ops.S

diff --git a/arch/loongarch/kvm/csr_ops.S b/arch/loongarch/kvm/csr_ops.S
new file mode 100644
index 000000000000..962b96d8291a
--- /dev/null
+++ b/arch/loongarch/kvm/csr_ops.S
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
+ */
+
+#include <asm/regdef.h>
+#include <linux/linkage.h>
+	.text
+	.section        .text
+	.cfi_sections   .debug_frame
+/*
+ * we have splited hw gcsr into three parts, so we can
+ * calculate the code offset by gcsrid and jump here to
+ * run the gcsrwr instruction.
+ */
+SYM_FUNC_START(set_hw_gcsr)
+	addi.d      t0,   a0,   0
+	addi.w      t1,   zero, 96
+	bltu        t1,   t0,   1f
+	la.pcrel    t0,   10f
+	alsl.d      t0,   a0,   t0, 3
+	jirl        zero, t0,   0
+1:
+	addi.w      t1,   a0,   -128
+	addi.w      t2,   zero, 15
+	bltu        t2,   t1,   2f
+	la.pcrel    t0,   11f
+	alsl.d      t0,   t1,   t0, 3
+	jirl        zero, t0,   0
+2:
+	addi.w      t1,   a0,   -384
+	addi.w      t2,   zero, 3
+	bltu        t2,   t1,   3f
+	la.pcrel    t0,   12f
+	alsl.d      t0,   t1,   t0, 3
+	jirl        zero, t0,   0
+3:
+	addi.w      a0,   zero, -1
+	jirl        zero, ra,   0
+/*
+ * write guest csr
+ * 0x05000000 | (LOONGARCH_CSR_XXX << 10) | 1 << 5 | a1
+ * range from 0x0(KVM_CSR_CRMD) to 0x60 (KVM_CSR_LLBCTL)
+ */
+10:
+	csrnum = 0
+	.rept 0x61
+		.word 0x05000020 | csrnum << 10 | 5
+		jirl zero, ra, 0
+		csrnum = csrnum + 1
+	.endr
+/*
+ * write guest csr
+ * 0x05000000 | (LOONGARCH_CSR_XXX << 10) | 1<<5 | a1
+ * range from 0x80 (KVM_CSR_IMPCTL1) to 0x8f (KVM_CSR_TLBRPRMD)
+ */
+11:
+	csrnum = 0x80
+	.rept 0x10
+		.word 0x05000020 | csrnum << 10 | 5
+		jirl zero, ra, 0
+		csrnum = csrnum + 1
+	.endr
+/*
+ * write guest csr
+ * 0x05000000 | (LOONGARCH_CSR_XXX << 10) | 1<<5 | a1
+ * range from 0x180(KVM_CSR_DMWIN0) to 0x183(KVM_CSR_DMWIN3)
+ */
+12:
+	csrnum = 0x180
+	.rept 0x4
+		.word 0x05000020 | csrnum << 10 | 5
+		jirl zero, ra, 0
+		csrnum = csrnum + 1
+	.endr
+SYM_FUNC_END(set_hw_gcsr)
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 651ae5ca0691..9ad6a285cbb4 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -13,6 +13,212 @@
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
+int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *v)
+{
+	unsigned long val;
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+
+	if (id >= CSR_ALL_SIZE || !(get_gcsr_flag(id) & (HW_GCSR | SW_GCSR)))
+		return -EINVAL;
+
+	if (id == LOONGARCH_CSR_ESTAT) {
+		/* interrupt status IP0 -- IP7 from GINTC */
+		val = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_GINTC) & 0xff;
+		*v = kvm_read_sw_gcsr(csr, id) | (val << 2);
+		return 0;
+	}
+
+	/*
+	 * get software csr state if csrid is valid, since software
+	 * csr state is consistent with hardware
+	 */
+	*v = kvm_read_sw_gcsr(csr, id);
+
+	return 0;
+}
+
+int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
+{
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+	int ret = 0, gintc;
+
+	if (id >= CSR_ALL_SIZE || !(get_gcsr_flag(id) & (HW_GCSR | SW_GCSR)))
+		return -EINVAL;
+
+	if (id == LOONGARCH_CSR_ESTAT) {
+		/* estat IP0~IP7 inject through guestexcept */
+		gintc = (val >> 2) & 0xff;
+		write_csr_gintc(gintc);
+		kvm_set_sw_gcsr(csr, LOONGARCH_CSR_GINTC, gintc);
+
+		gintc = val & ~(0xffUL << 2);
+		write_gcsr_estat(gintc);
+		kvm_set_sw_gcsr(csr, LOONGARCH_CSR_ESTAT, gintc);
+
+		return ret;
+	}
+
+	if (get_gcsr_flag(id) & HW_GCSR) {
+		set_hw_gcsr(id, val);
+		/* write sw gcsr to keep consistent with hardware */
+		kvm_write_sw_gcsr(csr, id, val);
+	} else
+		kvm_write_sw_gcsr(csr, id, val);
+
+	return ret;
+}
+
+static int _kvm_get_one_reg(struct kvm_vcpu *vcpu,
+		const struct kvm_one_reg *reg, s64 *v)
+{
+	int reg_idx, ret = 0;
+
+	if ((reg->id & KVM_REG_LOONGARCH_MASK) == KVM_REG_LOONGARCH_CSR) {
+		reg_idx = KVM_GET_IOC_CSRIDX(reg->id);
+		ret = _kvm_getcsr(vcpu, reg_idx, v);
+	} else if (reg->id == KVM_REG_LOONGARCH_COUNTER)
+		*v = drdtime() + vcpu->kvm->arch.time_offset;
+	else
+		ret = -EINVAL;
+
+	return ret;
+}
+
+static int _kvm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	int ret = -EINVAL;
+	s64 v;
+
+	if ((reg->id & KVM_REG_SIZE_MASK) != KVM_REG_SIZE_U64)
+		return ret;
+
+	if (_kvm_get_one_reg(vcpu, reg, &v))
+		return ret;
+
+	return put_user(v, (u64 __user *)(long)reg->addr);
+}
+
+static int _kvm_set_one_reg(struct kvm_vcpu *vcpu,
+			const struct kvm_one_reg *reg,
+			s64 v)
+{
+	int ret = 0;
+	unsigned long flags;
+	u64 val;
+	int reg_idx;
+
+	val = v;
+	if ((reg->id & KVM_REG_LOONGARCH_MASK) == KVM_REG_LOONGARCH_CSR) {
+		reg_idx = KVM_GET_IOC_CSRIDX(reg->id);
+		ret = _kvm_setcsr(vcpu, reg_idx, val);
+	} else if (reg->id == KVM_REG_LOONGARCH_COUNTER) {
+		local_irq_save(flags);
+		/*
+		 * gftoffset is relative with board, not vcpu
+		 * only set for the first time for smp system
+		 */
+		if (vcpu->vcpu_id == 0)
+			vcpu->kvm->arch.time_offset = (signed long)(v - drdtime());
+		write_csr_gcntc((ulong)vcpu->kvm->arch.time_offset);
+		local_irq_restore(flags);
+	} else if (reg->id == KVM_REG_LOONGARCH_VCPU_RESET) {
+		kvm_reset_timer(vcpu);
+		memset(&vcpu->arch.irq_pending, 0, sizeof(vcpu->arch.irq_pending));
+		memset(&vcpu->arch.irq_clear, 0, sizeof(vcpu->arch.irq_clear));
+	} else
+		ret = -EINVAL;
+
+	return ret;
+}
+
+static int _kvm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	s64 v;
+	int ret = -EINVAL;
+
+	if ((reg->id & KVM_REG_SIZE_MASK) != KVM_REG_SIZE_U64)
+		return ret;
+
+	if (get_user(v, (u64 __user *)(long)reg->addr))
+		return ret;
+
+	return _kvm_set_one_reg(vcpu, reg, v);
+}
+
+int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -ENOIOCTLCMD;
+}
+
+int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -ENOIOCTLCMD;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	int i;
+
+	vcpu_load(vcpu);
+
+	for (i = 0; i < ARRAY_SIZE(vcpu->arch.gprs); i++)
+		regs->gpr[i] = vcpu->arch.gprs[i];
+
+	regs->pc = vcpu->arch.pc;
+
+	vcpu_put(vcpu);
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	int i;
+
+	vcpu_load(vcpu);
+
+	for (i = 1; i < ARRAY_SIZE(vcpu->arch.gprs); i++)
+		vcpu->arch.gprs[i] = regs->gpr[i];
+	vcpu->arch.gprs[0] = 0; /* zero is special, and cannot be set. */
+	vcpu->arch.pc = regs->pc;
+
+	vcpu_put(vcpu);
+	return 0;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+			 unsigned int ioctl, unsigned long arg)
+{
+	struct kvm_vcpu *vcpu = filp->private_data;
+	void __user *argp = (void __user *)arg;
+	long r;
+
+	vcpu_load(vcpu);
+
+	switch (ioctl) {
+	case KVM_SET_ONE_REG:
+	case KVM_GET_ONE_REG: {
+		struct kvm_one_reg reg;
+
+		r = -EFAULT;
+		if (copy_from_user(&reg, argp, sizeof(reg)))
+			break;
+		if (ioctl == KVM_SET_ONE_REG)
+			r = _kvm_set_reg(vcpu, &reg);
+		else
+			r = _kvm_get_reg(vcpu, &reg);
+		break;
+	}
+	default:
+		r = -ENOIOCTLCMD;
+		break;
+	}
+
+	vcpu_put(vcpu);
+	return r;
+}
+
 int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
 {
 	return 0;
-- 
2.31.1