LoongArch: KVM: Add IPI read and write function

Add implementation of IPI interrupt controller's address space read and
write function simulation.

Signed-off-by: Min Zhou <zhoumin@loongson.cn>
Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

3 files changed, 291 insertions, 2 deletions

diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 8e5393d21fcb..a1de884ebb44 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -45,6 +45,8 @@ struct kvm_vm_stat {
 	struct kvm_vm_stat_generic generic;
 	u64 pages;
 	u64 hugepages;
+	u64 ipi_read_exits;
+	u64 ipi_write_exits;
 };
 
 struct kvm_vcpu_stat {
diff --git a/arch/loongarch/include/asm/kvm_ipi.h b/arch/loongarch/include/asm/kvm_ipi.h
index baaa6253e4dc..060163dfb4a3 100644
--- a/arch/loongarch/include/asm/kvm_ipi.h
+++ b/arch/loongarch/include/asm/kvm_ipi.h
@@ -28,6 +28,18 @@ struct ipi_state {
 #define IOCSR_IPI_BASE		0x1000
 #define IOCSR_IPI_SIZE		0x160
 
+#define IOCSR_IPI_STATUS	0x000
+#define IOCSR_IPI_EN		0x004
+#define IOCSR_IPI_SET		0x008
+#define IOCSR_IPI_CLEAR		0x00c
+#define IOCSR_IPI_BUF_20	0x020
+#define IOCSR_IPI_BUF_28	0x028
+#define IOCSR_IPI_BUF_30	0x030
+#define IOCSR_IPI_BUF_38	0x038
+#define IOCSR_IPI_SEND		0x040
+#define IOCSR_MAIL_SEND		0x048
+#define IOCSR_ANY_SEND		0x158
+
 int kvm_loongarch_register_ipi_device(void);
 
 #endif
diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c
index 9e45571ad76e..462d6ac084d3 100644
--- a/arch/loongarch/kvm/intc/ipi.c
+++ b/arch/loongarch/kvm/intc/ipi.c
@@ -7,18 +7,293 @@
 #include <asm/kvm_ipi.h>
 #include <asm/kvm_vcpu.h>
 
+static void ipi_send(struct kvm *kvm, uint64_t data)
+{
+	int cpu, action;
+	uint32_t status;
+	struct kvm_vcpu *vcpu;
+	struct kvm_interrupt irq;
+
+	cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+	vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+	if (unlikely(vcpu == NULL)) {
+		kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+		return;
+	}
+
+	action = BIT(data & 0x1f);
+	spin_lock(&vcpu->arch.ipi_state.lock);
+	status = vcpu->arch.ipi_state.status;
+	vcpu->arch.ipi_state.status |= action;
+	spin_unlock(&vcpu->arch.ipi_state.lock);
+	if (status == 0) {
+		irq.irq = LARCH_INT_IPI;
+		kvm_vcpu_ioctl_interrupt(vcpu, &irq);
+	}
+}
+
+static void ipi_clear(struct kvm_vcpu *vcpu, uint64_t data)
+{
+	uint32_t status;
+	struct kvm_interrupt irq;
+
+	spin_lock(&vcpu->arch.ipi_state.lock);
+	vcpu->arch.ipi_state.status &= ~data;
+	status = vcpu->arch.ipi_state.status;
+	spin_unlock(&vcpu->arch.ipi_state.lock);
+	if (status == 0) {
+		irq.irq = -LARCH_INT_IPI;
+		kvm_vcpu_ioctl_interrupt(vcpu, &irq);
+	}
+}
+
+static uint64_t read_mailbox(struct kvm_vcpu *vcpu, int offset, int len)
+{
+	uint64_t data = 0;
+
+	spin_lock(&vcpu->arch.ipi_state.lock);
+	data = *(ulong *)((void *)vcpu->arch.ipi_state.buf + (offset - 0x20));
+	spin_unlock(&vcpu->arch.ipi_state.lock);
+
+	switch (len) {
+	case 1:
+		return data & 0xff;
+	case 2:
+		return data & 0xffff;
+	case 4:
+		return data & 0xffffffff;
+	case 8:
+		return data;
+	default:
+		kvm_err("%s: unknown data len: %d\n", __func__, len);
+		return 0;
+	}
+}
+
+static void write_mailbox(struct kvm_vcpu *vcpu, int offset, uint64_t data, int len)
+{
+	void *pbuf;
+
+	spin_lock(&vcpu->arch.ipi_state.lock);
+	pbuf = (void *)vcpu->arch.ipi_state.buf + (offset - 0x20);
+
+	switch (len) {
+	case 1:
+		*(unsigned char *)pbuf = (unsigned char)data;
+		break;
+	case 2:
+		*(unsigned short *)pbuf = (unsigned short)data;
+		break;
+	case 4:
+		*(unsigned int *)pbuf = (unsigned int)data;
+		break;
+	case 8:
+		*(unsigned long *)pbuf = (unsigned long)data;
+		break;
+	default:
+		kvm_err("%s: unknown data len: %d\n", __func__, len);
+	}
+	spin_unlock(&vcpu->arch.ipi_state.lock);
+}
+
+static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data)
+{
+	int i, ret;
+	uint32_t val = 0, mask = 0;
+
+	/*
+	 * Bit 27-30 is mask for byte writing.
+	 * If the mask is 0, we need not to do anything.
+	 */
+	if ((data >> 27) & 0xf) {
+		/* Read the old val */
+		ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val);
+		if (unlikely(ret)) {
+			kvm_err("%s: : read date from addr %llx failed\n", __func__, addr);
+			return ret;
+		}
+		/* Construct the mask by scanning the bit 27-30 */
+		for (i = 0; i < 4; i++) {
+			if (data & (BIT(27 + i)))
+				mask |= (0xff << (i * 8));
+		}
+		/* Save the old part of val */
+		val &= mask;
+	}
+	val |= ((uint32_t)(data >> 32) & ~mask);
+	ret = kvm_io_bus_write(vcpu, KVM_IOCSR_BUS, addr, sizeof(val), &val);
+	if (unlikely(ret))
+		kvm_err("%s: : write date to addr %llx failed\n", __func__, addr);
+
+	return ret;
+}
+
+static int mail_send(struct kvm *kvm, uint64_t data)
+{
+	int cpu, mailbox, offset;
+	struct kvm_vcpu *vcpu;
+
+	cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+	vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+	if (unlikely(vcpu == NULL)) {
+		kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+		return -EINVAL;
+	}
+	mailbox = ((data & 0xffffffff) >> 2) & 0x7;
+	offset = IOCSR_IPI_BASE + IOCSR_IPI_BUF_20 + mailbox * 4;
+
+	return send_ipi_data(vcpu, offset, data);
+}
+
+static int any_send(struct kvm *kvm, uint64_t data)
+{
+	int cpu, offset;
+	struct kvm_vcpu *vcpu;
+
+	cpu = ((data & 0xffffffff) >> 16) & 0x3ff;
+	vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
+	if (unlikely(vcpu == NULL)) {
+		kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
+		return -EINVAL;
+	}
+	offset = data & 0xffff;
+
+	return send_ipi_data(vcpu, offset, data);
+}
+
+static int loongarch_ipi_readl(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *val)
+{
+	int ret = 0;
+	uint32_t offset;
+	uint64_t res = 0;
+
+	offset = (uint32_t)(addr & 0x1ff);
+	WARN_ON_ONCE(offset & (len - 1));
+
+	switch (offset) {
+	case IOCSR_IPI_STATUS:
+		spin_lock(&vcpu->arch.ipi_state.lock);
+		res = vcpu->arch.ipi_state.status;
+		spin_unlock(&vcpu->arch.ipi_state.lock);
+		break;
+	case IOCSR_IPI_EN:
+		spin_lock(&vcpu->arch.ipi_state.lock);
+		res = vcpu->arch.ipi_state.en;
+		spin_unlock(&vcpu->arch.ipi_state.lock);
+		break;
+	case IOCSR_IPI_SET:
+		res = 0;
+		break;
+	case IOCSR_IPI_CLEAR:
+		res = 0;
+		break;
+	case IOCSR_IPI_BUF_20 ... IOCSR_IPI_BUF_38 + 7:
+		if (offset + len > IOCSR_IPI_BUF_38 + 8) {
+			kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
+				__func__, offset, len);
+			ret = -EINVAL;
+			break;
+		}
+		res = read_mailbox(vcpu, offset, len);
+		break;
+	default:
+		kvm_err("%s: unknown addr: %llx\n", __func__, addr);
+		ret = -EINVAL;
+		break;
+	}
+	*(uint64_t *)val = res;
+
+	return ret;
+}
+
+static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr, int len, const void *val)
+{
+	int ret = 0;
+	uint64_t data;
+	uint32_t offset;
+
+	data = *(uint64_t *)val;
+
+	offset = (uint32_t)(addr & 0x1ff);
+	WARN_ON_ONCE(offset & (len - 1));
+
+	switch (offset) {
+	case IOCSR_IPI_STATUS:
+		ret = -EINVAL;
+		break;
+	case IOCSR_IPI_EN:
+		spin_lock(&vcpu->arch.ipi_state.lock);
+		vcpu->arch.ipi_state.en = data;
+		spin_unlock(&vcpu->arch.ipi_state.lock);
+		break;
+	case IOCSR_IPI_SET:
+		ret = -EINVAL;
+		break;
+	case IOCSR_IPI_CLEAR:
+		/* Just clear the status of the current vcpu */
+		ipi_clear(vcpu, data);
+		break;
+	case IOCSR_IPI_BUF_20 ... IOCSR_IPI_BUF_38 + 7:
+		if (offset + len > IOCSR_IPI_BUF_38 + 8) {
+			kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
+				__func__, offset, len);
+			ret = -EINVAL;
+			break;
+		}
+		write_mailbox(vcpu, offset, data, len);
+		break;
+	case IOCSR_IPI_SEND:
+		ipi_send(vcpu->kvm, data);
+		break;
+	case IOCSR_MAIL_SEND:
+		ret = mail_send(vcpu->kvm, *(uint64_t *)val);
+		break;
+	case IOCSR_ANY_SEND:
+		ret = any_send(vcpu->kvm, *(uint64_t *)val);
+		break;
+	default:
+		kvm_err("%s: unknown addr: %llx\n", __func__, addr);
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
 static int kvm_ipi_read(struct kvm_vcpu *vcpu,
 			struct kvm_io_device *dev,
 			gpa_t addr, int len, void *val)
 {
-	return 0;
+	int ret;
+	struct loongarch_ipi *ipi;
+
+	ipi = vcpu->kvm->arch.ipi;
+	if (!ipi) {
+		kvm_err("%s: ipi irqchip not valid!\n", __func__);
+		return -EINVAL;
+	}
+	ipi->kvm->stat.ipi_read_exits++;
+	ret = loongarch_ipi_readl(vcpu, addr, len, val);
+
+	return ret;
 }
 
 static int kvm_ipi_write(struct kvm_vcpu *vcpu,
 			struct kvm_io_device *dev,
 			gpa_t addr, int len, const void *val)
 {
-	return 0;
+	int ret;
+	struct loongarch_ipi *ipi;
+
+	ipi = vcpu->kvm->arch.ipi;
+	if (!ipi) {
+		kvm_err("%s: ipi irqchip not valid!\n", __func__);
+		return -EINVAL;
+	}
+	ipi->kvm->stat.ipi_write_exits++;
+	ret = loongarch_ipi_writel(vcpu, addr, len, val);
+
+	return ret;
 }
 
 static const struct kvm_io_device_ops kvm_ipi_ops = {