1 files changed, 272 insertions, 2 deletions

diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
index 4f1286fc7f17..585a3b42c52c 100644
--- a/arch/riscv/kvm/aia.c
+++ b/arch/riscv/kvm/aia.c
@@ -8,11 +8,49 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/kvm_host.h>
+#include <linux/percpu.h>
+#include <linux/spinlock.h>
 #include <asm/hwcap.h>
+#include <asm/kvm_aia_imsic.h>
 
+struct aia_hgei_control {
+	raw_spinlock_t lock;
+	unsigned long free_bitmap;
+	struct kvm_vcpu *owners[BITS_PER_LONG];
+};
+static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei);
+static int hgei_parent_irq;
+
+unsigned int kvm_riscv_aia_nr_hgei;
+unsigned int kvm_riscv_aia_max_ids;
 DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available);
 
+static int aia_find_hgei(struct kvm_vcpu *owner)
+{
+	int i, hgei;
+	unsigned long flags;
+	struct aia_hgei_control *hgctrl = get_cpu_ptr(&aia_hgei);
+
+	raw_spin_lock_irqsave(&hgctrl->lock, flags);
+
+	hgei = -1;
+	for (i = 1; i <= kvm_riscv_aia_nr_hgei; i++) {
+		if (hgctrl->owners[i] == owner) {
+			hgei = i;
+			break;
+		}
+	}
+
+	raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+
+	put_cpu_ptr(&aia_hgei);
+	return hgei;
+}
+
 static void aia_set_hvictl(bool ext_irq_pending)
 {
 	unsigned long hvictl;
@@ -56,6 +94,7 @@ void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu)
 
 bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask)
 {
+	int hgei;
 	unsigned long seip;
 
 	if (!kvm_riscv_aia_available())
@@ -74,6 +113,10 @@ bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask)
 	if (!kvm_riscv_aia_initialized(vcpu->kvm) || !seip)
 		return false;
 
+	hgei = aia_find_hgei(vcpu);
+	if (hgei > 0)
+		return !!(csr_read(CSR_HGEIP) & BIT(hgei));
+
 	return false;
 }
 
@@ -323,8 +366,6 @@ static int aia_rmw_iprio(struct kvm_vcpu *vcpu, unsigned int isel,
 	return KVM_INSN_CONTINUE_NEXT_SEPC;
 }
 
-#define IMSIC_FIRST	0x70
-#define IMSIC_LAST	0xff
 int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num,
 				unsigned long *val, unsigned long new_val,
 				unsigned long wr_mask)
@@ -348,6 +389,143 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num,
 	return KVM_INSN_EXIT_TO_USER_SPACE;
 }
 
+int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner,
+			     void __iomem **hgei_va, phys_addr_t *hgei_pa)
+{
+	int ret = -ENOENT;
+	unsigned long flags;
+	struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu);
+
+	if (!kvm_riscv_aia_available() || !hgctrl)
+		return -ENODEV;
+
+	raw_spin_lock_irqsave(&hgctrl->lock, flags);
+
+	if (hgctrl->free_bitmap) {
+		ret = __ffs(hgctrl->free_bitmap);
+		hgctrl->free_bitmap &= ~BIT(ret);
+		hgctrl->owners[ret] = owner;
+	}
+
+	raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+
+	/* TODO: To be updated later by AIA IMSIC HW guest file support */
+	if (hgei_va)
+		*hgei_va = NULL;
+	if (hgei_pa)
+		*hgei_pa = 0;
+
+	return ret;
+}
+
+void kvm_riscv_aia_free_hgei(int cpu, int hgei)
+{
+	unsigned long flags;
+	struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu);
+
+	if (!kvm_riscv_aia_available() || !hgctrl)
+		return;
+
+	raw_spin_lock_irqsave(&hgctrl->lock, flags);
+
+	if (hgei > 0 && hgei <= kvm_riscv_aia_nr_hgei) {
+		if (!(hgctrl->free_bitmap & BIT(hgei))) {
+			hgctrl->free_bitmap |= BIT(hgei);
+			hgctrl->owners[hgei] = NULL;
+		}
+	}
+
+	raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+}
+
+void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable)
+{
+	int hgei;
+
+	if (!kvm_riscv_aia_available())
+		return;
+
+	hgei = aia_find_hgei(owner);
+	if (hgei > 0) {
+		if (enable)
+			csr_set(CSR_HGEIE, BIT(hgei));
+		else
+			csr_clear(CSR_HGEIE, BIT(hgei));
+	}
+}
+
+static irqreturn_t hgei_interrupt(int irq, void *dev_id)
+{
+	int i;
+	unsigned long hgei_mask, flags;
+	struct aia_hgei_control *hgctrl = get_cpu_ptr(&aia_hgei);
+
+	hgei_mask = csr_read(CSR_HGEIP) & csr_read(CSR_HGEIE);
+	csr_clear(CSR_HGEIE, hgei_mask);
+
+	raw_spin_lock_irqsave(&hgctrl->lock, flags);
+
+	for_each_set_bit(i, &hgei_mask, BITS_PER_LONG) {
+		if (hgctrl->owners[i])
+			kvm_vcpu_kick(hgctrl->owners[i]);
+	}
+
+	raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+
+	put_cpu_ptr(&aia_hgei);
+	return IRQ_HANDLED;
+}
+
+static int aia_hgei_init(void)
+{
+	int cpu, rc;
+	struct irq_domain *domain;
+	struct aia_hgei_control *hgctrl;
+
+	/* Initialize per-CPU guest external interrupt line management */
+	for_each_possible_cpu(cpu) {
+		hgctrl = per_cpu_ptr(&aia_hgei, cpu);
+		raw_spin_lock_init(&hgctrl->lock);
+		if (kvm_riscv_aia_nr_hgei) {
+			hgctrl->free_bitmap =
+				BIT(kvm_riscv_aia_nr_hgei + 1) - 1;
+			hgctrl->free_bitmap &= ~BIT(0);
+		} else
+			hgctrl->free_bitmap = 0;
+	}
+
+	/* Find INTC irq domain */
+	domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
+					  DOMAIN_BUS_ANY);
+	if (!domain) {
+		kvm_err("unable to find INTC domain\n");
+		return -ENOENT;
+	}
+
+	/* Map per-CPU SGEI interrupt from INTC domain */
+	hgei_parent_irq = irq_create_mapping(domain, IRQ_S_GEXT);
+	if (!hgei_parent_irq) {
+		kvm_err("unable to map SGEI IRQ\n");
+		return -ENOMEM;
+	}
+
+	/* Request per-CPU SGEI interrupt */
+	rc = request_percpu_irq(hgei_parent_irq, hgei_interrupt,
+				"riscv-kvm", &aia_hgei);
+	if (rc) {
+		kvm_err("failed to request SGEI IRQ\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static void aia_hgei_exit(void)
+{
+	/* Free per-CPU SGEI interrupt */
+	free_percpu_irq(hgei_parent_irq, &aia_hgei);
+}
+
 void kvm_riscv_aia_enable(void)
 {
 	if (!kvm_riscv_aia_available())
@@ -362,21 +540,105 @@ void kvm_riscv_aia_enable(void)
 	csr_write(CSR_HVIPRIO1H, 0x0);
 	csr_write(CSR_HVIPRIO2H, 0x0);
 #endif
+
+	/* Enable per-CPU SGEI interrupt */
+	enable_percpu_irq(hgei_parent_irq,
+			  irq_get_trigger_type(hgei_parent_irq));
+	csr_set(CSR_HIE, BIT(IRQ_S_GEXT));
 }
 
 void kvm_riscv_aia_disable(void)
 {
+	int i;
+	unsigned long flags;
+	struct kvm_vcpu *vcpu;
+	struct aia_hgei_control *hgctrl;
+
 	if (!kvm_riscv_aia_available())
 		return;
+	hgctrl = get_cpu_ptr(&aia_hgei);
+
+	/* Disable per-CPU SGEI interrupt */
+	csr_clear(CSR_HIE, BIT(IRQ_S_GEXT));
+	disable_percpu_irq(hgei_parent_irq);
 
 	aia_set_hvictl(false);
+
+	raw_spin_lock_irqsave(&hgctrl->lock, flags);
+
+	for (i = 0; i <= kvm_riscv_aia_nr_hgei; i++) {
+		vcpu = hgctrl->owners[i];
+		if (!vcpu)
+			continue;
+
+		/*
+		 * We release hgctrl->lock before notifying IMSIC
+		 * so that we don't have lock ordering issues.
+		 */
+		raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+
+		/* Notify IMSIC */
+		kvm_riscv_vcpu_aia_imsic_release(vcpu);
+
+		/*
+		 * Wakeup VCPU if it was blocked so that it can
+		 * run on other HARTs
+		 */
+		if (csr_read(CSR_HGEIE) & BIT(i)) {
+			csr_clear(CSR_HGEIE, BIT(i));
+			kvm_vcpu_kick(vcpu);
+		}
+
+		raw_spin_lock_irqsave(&hgctrl->lock, flags);
+	}
+
+	raw_spin_unlock_irqrestore(&hgctrl->lock, flags);
+
+	put_cpu_ptr(&aia_hgei);
 }
 
 int kvm_riscv_aia_init(void)
 {
+	int rc;
+
 	if (!riscv_isa_extension_available(NULL, SxAIA))
 		return -ENODEV;
 
+	/* Figure-out number of bits in HGEIE */
+	csr_write(CSR_HGEIE, -1UL);
+	kvm_riscv_aia_nr_hgei = fls_long(csr_read(CSR_HGEIE));
+	csr_write(CSR_HGEIE, 0);
+	if (kvm_riscv_aia_nr_hgei)
+		kvm_riscv_aia_nr_hgei--;
+
+	/*
+	 * Number of usable HGEI lines should be minimum of per-HART
+	 * IMSIC guest files and number of bits in HGEIE
+	 *
+	 * TODO: To be updated later by AIA IMSIC HW guest file support
+	 */
+	kvm_riscv_aia_nr_hgei = 0;
+
+	/*
+	 * Find number of guest MSI IDs
+	 *
+	 * TODO: To be updated later by AIA IMSIC HW guest file support
+	 */
+	kvm_riscv_aia_max_ids = IMSIC_MAX_ID;
+
+	/* Initialize guest external interrupt line management */
+	rc = aia_hgei_init();
+	if (rc)
+		return rc;
+
+	/* Register device operations */
+	rc = kvm_register_device_ops(&kvm_riscv_aia_device_ops,
+				     KVM_DEV_TYPE_RISCV_AIA);
+	if (rc) {
+		aia_hgei_exit();
+		return rc;
+	}
+
 	/* Enable KVM AIA support */
 	static_branch_enable(&kvm_riscv_aia_available);
 
@@ -385,4 +647,12 @@ int kvm_riscv_aia_init(void)
 
 void kvm_riscv_aia_exit(void)
 {
+	if (!kvm_riscv_aia_available())
+		return;
+
+	/* Unregister device operations */
+	kvm_unregister_device_ops(KVM_DEV_TYPE_RISCV_AIA);
+
+	/* Cleanup the HGEI state */
+	aia_hgei_exit();
 }