1 files changed, 421 insertions, 0 deletions

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
new file mode 100644
index 0000000000..9cd97091c7
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -0,0 +1,421 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <asm/sbi.h>
+#include <asm/kvm_vcpu_sbi.h>
+
+#ifndef CONFIG_RISCV_SBI_V01
+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
+	.extid_start = -1UL,
+	.extid_end = -1UL,
+	.handler = NULL,
+};
+#endif
+
+#ifndef CONFIG_RISCV_PMU_SBI
+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
+	.extid_start = -1UL,
+	.extid_end = -1UL,
+	.handler = NULL,
+};
+#endif
+
+struct kvm_riscv_sbi_extension_entry {
+	enum KVM_RISCV_SBI_EXT_ID ext_idx;
+	const struct kvm_vcpu_sbi_extension *ext_ptr;
+};
+
+static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = {
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_V01,
+		.ext_ptr = &vcpu_sbi_ext_v01,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_MAX, /* Can't be disabled */
+		.ext_ptr = &vcpu_sbi_ext_base,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_TIME,
+		.ext_ptr = &vcpu_sbi_ext_time,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_IPI,
+		.ext_ptr = &vcpu_sbi_ext_ipi,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_RFENCE,
+		.ext_ptr = &vcpu_sbi_ext_rfence,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_SRST,
+		.ext_ptr = &vcpu_sbi_ext_srst,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_HSM,
+		.ext_ptr = &vcpu_sbi_ext_hsm,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_PMU,
+		.ext_ptr = &vcpu_sbi_ext_pmu,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL,
+		.ext_ptr = &vcpu_sbi_ext_experimental,
+	},
+	{
+		.ext_idx = KVM_RISCV_SBI_EXT_VENDOR,
+		.ext_ptr = &vcpu_sbi_ext_vendor,
+	},
+};
+
+void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+
+	vcpu->arch.sbi_context.return_handled = 0;
+	vcpu->stat.ecall_exit_stat++;
+	run->exit_reason = KVM_EXIT_RISCV_SBI;
+	run->riscv_sbi.extension_id = cp->a7;
+	run->riscv_sbi.function_id = cp->a6;
+	run->riscv_sbi.args[0] = cp->a0;
+	run->riscv_sbi.args[1] = cp->a1;
+	run->riscv_sbi.args[2] = cp->a2;
+	run->riscv_sbi.args[3] = cp->a3;
+	run->riscv_sbi.args[4] = cp->a4;
+	run->riscv_sbi.args[5] = cp->a5;
+	run->riscv_sbi.ret[0] = cp->a0;
+	run->riscv_sbi.ret[1] = cp->a1;
+}
+
+void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
+				     struct kvm_run *run,
+				     u32 type, u64 reason)
+{
+	unsigned long i;
+	struct kvm_vcpu *tmp;
+
+	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
+		tmp->arch.power_off = true;
+	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
+
+	memset(&run->system_event, 0, sizeof(run->system_event));
+	run->system_event.type = type;
+	run->system_event.ndata = 1;
+	run->system_event.data[0] = reason;
+	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+}
+
+int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+
+	/* Handle SBI return only once */
+	if (vcpu->arch.sbi_context.return_handled)
+		return 0;
+	vcpu->arch.sbi_context.return_handled = 1;
+
+	/* Update return values */
+	cp->a0 = run->riscv_sbi.ret[0];
+	cp->a1 = run->riscv_sbi.ret[1];
+
+	/* Move to next instruction */
+	vcpu->arch.guest_context.sepc += 4;
+
+	return 0;
+}
+
+static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu,
+					 unsigned long reg_num,
+					 unsigned long reg_val)
+{
+	unsigned long i;
+	const struct kvm_riscv_sbi_extension_entry *sext = NULL;
+	struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
+
+	if (reg_num >= KVM_RISCV_SBI_EXT_MAX)
+		return -ENOENT;
+
+	if (reg_val != 1 && reg_val != 0)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
+		if (sbi_ext[i].ext_idx == reg_num) {
+			sext = &sbi_ext[i];
+			break;
+		}
+	}
+	if (!sext)
+		return -ENOENT;
+
+	/*
+	 * We can't set the extension status to available here, since it may
+	 * have a probe() function which needs to confirm availability first,
+	 * but it may be too early to call that here. We can set the status to
+	 * unavailable, though.
+	 */
+	if (!reg_val)
+		scontext->ext_status[sext->ext_idx] =
+			KVM_RISCV_SBI_EXT_UNAVAILABLE;
+
+	return 0;
+}
+
+static int riscv_vcpu_get_sbi_ext_single(struct kvm_vcpu *vcpu,
+					 unsigned long reg_num,
+					 unsigned long *reg_val)
+{
+	unsigned long i;
+	const struct kvm_riscv_sbi_extension_entry *sext = NULL;
+	struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
+
+	if (reg_num >= KVM_RISCV_SBI_EXT_MAX)
+		return -ENOENT;
+
+	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
+		if (sbi_ext[i].ext_idx == reg_num) {
+			sext = &sbi_ext[i];
+			break;
+		}
+	}
+	if (!sext)
+		return -ENOENT;
+
+	/*
+	 * If the extension status is still uninitialized, then we should probe
+	 * to determine if it's available, but it may be too early to do that
+	 * here. The best we can do is report that the extension has not been
+	 * disabled, i.e. we return 1 when the extension is available and also
+	 * when it only may be available.
+	 */
+	*reg_val = scontext->ext_status[sext->ext_idx] !=
+				KVM_RISCV_SBI_EXT_UNAVAILABLE;
+
+	return 0;
+}
+
+static int riscv_vcpu_set_sbi_ext_multi(struct kvm_vcpu *vcpu,
+					unsigned long reg_num,
+					unsigned long reg_val, bool enable)
+{
+	unsigned long i, ext_id;
+
+	if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
+		return -ENOENT;
+
+	for_each_set_bit(i, &reg_val, BITS_PER_LONG) {
+		ext_id = i + reg_num * BITS_PER_LONG;
+		if (ext_id >= KVM_RISCV_SBI_EXT_MAX)
+			break;
+
+		riscv_vcpu_set_sbi_ext_single(vcpu, ext_id, enable);
+	}
+
+	return 0;
+}
+
+static int riscv_vcpu_get_sbi_ext_multi(struct kvm_vcpu *vcpu,
+					unsigned long reg_num,
+					unsigned long *reg_val)
+{
+	unsigned long i, ext_id, ext_val;
+
+	if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
+		return -ENOENT;
+
+	for (i = 0; i < BITS_PER_LONG; i++) {
+		ext_id = i + reg_num * BITS_PER_LONG;
+		if (ext_id >= KVM_RISCV_SBI_EXT_MAX)
+			break;
+
+		ext_val = 0;
+		riscv_vcpu_get_sbi_ext_single(vcpu, ext_id, &ext_val);
+		if (ext_val)
+			*reg_val |= KVM_REG_RISCV_SBI_MULTI_MASK(ext_id);
+	}
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_set_reg_sbi_ext(struct kvm_vcpu *vcpu,
+				   const struct kvm_one_reg *reg)
+{
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_SBI_EXT);
+	unsigned long reg_val, reg_subtype;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	if (vcpu->arch.ran_atleast_once)
+		return -EBUSY;
+
+	reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
+	reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
+
+	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	switch (reg_subtype) {
+	case KVM_REG_RISCV_SBI_SINGLE:
+		return riscv_vcpu_set_sbi_ext_single(vcpu, reg_num, reg_val);
+	case KVM_REG_RISCV_SBI_MULTI_EN:
+		return riscv_vcpu_set_sbi_ext_multi(vcpu, reg_num, reg_val, true);
+	case KVM_REG_RISCV_SBI_MULTI_DIS:
+		return riscv_vcpu_set_sbi_ext_multi(vcpu, reg_num, reg_val, false);
+	default:
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_get_reg_sbi_ext(struct kvm_vcpu *vcpu,
+				   const struct kvm_one_reg *reg)
+{
+	int rc;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_SBI_EXT);
+	unsigned long reg_val, reg_subtype;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
+	reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
+
+	reg_val = 0;
+	switch (reg_subtype) {
+	case KVM_REG_RISCV_SBI_SINGLE:
+		rc = riscv_vcpu_get_sbi_ext_single(vcpu, reg_num, &reg_val);
+		break;
+	case KVM_REG_RISCV_SBI_MULTI_EN:
+	case KVM_REG_RISCV_SBI_MULTI_DIS:
+		rc = riscv_vcpu_get_sbi_ext_multi(vcpu, reg_num, &reg_val);
+		if (!rc && reg_subtype == KVM_REG_RISCV_SBI_MULTI_DIS)
+			reg_val = ~reg_val;
+		break;
+	default:
+		rc = -ENOENT;
+	}
+	if (rc)
+		return rc;
+
+	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(
+				struct kvm_vcpu *vcpu, unsigned long extid)
+{
+	struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
+	const struct kvm_riscv_sbi_extension_entry *entry;
+	const struct kvm_vcpu_sbi_extension *ext;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
+		entry = &sbi_ext[i];
+		ext = entry->ext_ptr;
+
+		if (ext->extid_start <= extid && ext->extid_end >= extid) {
+			if (entry->ext_idx >= KVM_RISCV_SBI_EXT_MAX ||
+			    scontext->ext_status[entry->ext_idx] ==
+						KVM_RISCV_SBI_EXT_AVAILABLE)
+				return ext;
+			if (scontext->ext_status[entry->ext_idx] ==
+						KVM_RISCV_SBI_EXT_UNAVAILABLE)
+				return NULL;
+			if (ext->probe && !ext->probe(vcpu)) {
+				scontext->ext_status[entry->ext_idx] =
+					KVM_RISCV_SBI_EXT_UNAVAILABLE;
+				return NULL;
+			}
+
+			scontext->ext_status[entry->ext_idx] =
+				KVM_RISCV_SBI_EXT_AVAILABLE;
+			return ext;
+		}
+	}
+
+	return NULL;
+}
+
+int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	int ret = 1;
+	bool next_sepc = true;
+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+	const struct kvm_vcpu_sbi_extension *sbi_ext;
+	struct kvm_cpu_trap utrap = {0};
+	struct kvm_vcpu_sbi_return sbi_ret = {
+		.out_val = 0,
+		.err_val = 0,
+		.utrap = &utrap,
+	};
+	bool ext_is_v01 = false;
+
+	sbi_ext = kvm_vcpu_sbi_find_ext(vcpu, cp->a7);
+	if (sbi_ext && sbi_ext->handler) {
+#ifdef CONFIG_RISCV_SBI_V01
+		if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
+		    cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
+			ext_is_v01 = true;
+#endif
+		ret = sbi_ext->handler(vcpu, run, &sbi_ret);
+	} else {
+		/* Return error for unsupported SBI calls */
+		cp->a0 = SBI_ERR_NOT_SUPPORTED;
+		goto ecall_done;
+	}
+
+	/*
+	 * When the SBI extension returns a Linux error code, it exits the ioctl
+	 * loop and forwards the error to userspace.
+	 */
+	if (ret < 0) {
+		next_sepc = false;
+		goto ecall_done;
+	}
+
+	/* Handle special error cases i.e trap, exit or userspace forward */
+	if (sbi_ret.utrap->scause) {
+		/* No need to increment sepc or exit ioctl loop */
+		ret = 1;
+		sbi_ret.utrap->sepc = cp->sepc;
+		kvm_riscv_vcpu_trap_redirect(vcpu, sbi_ret.utrap);
+		next_sepc = false;
+		goto ecall_done;
+	}
+
+	/* Exit ioctl loop or Propagate the error code the guest */
+	if (sbi_ret.uexit) {
+		next_sepc = false;
+		ret = 0;
+	} else {
+		cp->a0 = sbi_ret.err_val;
+		ret = 1;
+	}
+ecall_done:
+	if (next_sepc)
+		cp->sepc += 4;
+	/* a1 should only be updated when we continue the ioctl loop */
+	if (!ext_is_v01 && ret == 1)
+		cp->a1 = sbi_ret.out_val;
+
+	return ret;
+}