KVM/MIPS32: Guest interrupt delivery.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 292 insertions, 0 deletions

diff --git a/arch/mips/kvm/kvm_mips_int.c b/arch/mips/kvm/kvm_mips_int.c
new file mode 100644
index 0000000..1e5de16
--- /dev/null
+++ b/arch/mips/kvm/kvm_mips_int.c
@@ -0,0 +1,243 @@
+/*
+* This file is subject to the terms and conditions of the GNU General Public
+* License.  See the file "COPYING" in the main directory of this archive
+* for more details.
+*
+* KVM/MIPS: Interrupt delivery
+*
+* Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
+* Authors: Sanjay Lal <sanjayl@kymasys.com>
+*/
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/bootmem.h>
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+
+#include <linux/kvm_host.h>
+
+#include "kvm_mips_int.h"
+
+void kvm_mips_queue_irq(struct kvm_vcpu *vcpu, uint32_t priority)
+{
+	set_bit(priority, &vcpu->arch.pending_exceptions);
+}
+
+void kvm_mips_dequeue_irq(struct kvm_vcpu *vcpu, uint32_t priority)
+{
+	clear_bit(priority, &vcpu->arch.pending_exceptions);
+}
+
+void kvm_mips_queue_timer_int_cb(struct kvm_vcpu *vcpu)
+{
+	/* Cause bits to reflect the pending timer interrupt,
+	 * the EXC code will be set when we are actually
+	 * delivering the interrupt:
+	 */
+	kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
+
+	/* Queue up an INT exception for the core */
+	kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_TIMER);
+
+}
+
+void kvm_mips_dequeue_timer_int_cb(struct kvm_vcpu *vcpu)
+{
+	kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
+	kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_TIMER);
+}
+
+void
+kvm_mips_queue_io_int_cb(struct kvm_vcpu *vcpu, struct kvm_mips_interrupt *irq)
+{
+	int intr = (int)irq->irq;
+
+	/* Cause bits to reflect the pending IO interrupt,
+	 * the EXC code will be set when we are actually
+	 * delivering the interrupt:
+	 */
+	switch (intr) {
+	case 2:
+		kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
+		/* Queue up an INT exception for the core */
+		kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IO);
+		break;
+
+	case 3:
+		kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
+		kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_1);
+		break;
+
+	case 4:
+		kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
+		kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_2);
+		break;
+
+	default:
+		break;
+	}
+
+}
+
+void
+kvm_mips_dequeue_io_int_cb(struct kvm_vcpu *vcpu,
+			   struct kvm_mips_interrupt *irq)
+{
+	int intr = (int)irq->irq;
+	switch (intr) {
+	case -2:
+		kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
+		kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IO);
+		break;
+
+	case -3:
+		kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
+		kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_1);
+		break;
+
+	case -4:
+		kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
+		kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_2);
+		break;
+
+	default:
+		break;
+	}
+
+}
+
+/* Deliver the interrupt of the corresponding priority, if possible. */
+int
+kvm_mips_irq_deliver_cb(struct kvm_vcpu *vcpu, unsigned int priority,
+			uint32_t cause)
+{
+	int allowed = 0;
+	uint32_t exccode;
+
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	switch (priority) {
+	case MIPS_EXC_INT_TIMER:
+		if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
+		    && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
+		    && (kvm_read_c0_guest_status(cop0) & IE_IRQ5)) {
+			allowed = 1;
+			exccode = T_INT;
+		}
+		break;
+
+	case MIPS_EXC_INT_IO:
+		if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
+		    && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
+		    && (kvm_read_c0_guest_status(cop0) & IE_IRQ0)) {
+			allowed = 1;
+			exccode = T_INT;
+		}
+		break;
+
+	case MIPS_EXC_INT_IPI_1:
+		if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
+		    && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
+		    && (kvm_read_c0_guest_status(cop0) & IE_IRQ1)) {
+			allowed = 1;
+			exccode = T_INT;
+		}
+		break;
+
+	case MIPS_EXC_INT_IPI_2:
+		if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
+		    && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
+		    && (kvm_read_c0_guest_status(cop0) & IE_IRQ2)) {
+			allowed = 1;
+			exccode = T_INT;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	/* Are we allowed to deliver the interrupt ??? */
+	if (allowed) {
+
+		if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+			/* save old pc */
+			kvm_write_c0_guest_epc(cop0, arch->pc);
+			kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+			if (cause & CAUSEF_BD)
+				kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+			else
+				kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+			kvm_debug("Delivering INT @ pc %#lx\n", arch->pc);
+
+		} else
+			kvm_err("Trying to deliver interrupt when EXL is already set\n");
+
+		kvm_change_c0_guest_cause(cop0, CAUSEF_EXCCODE,
+					  (exccode << CAUSEB_EXCCODE));
+
+		/* XXXSL Set PC to the interrupt exception entry point */
+		if (kvm_read_c0_guest_cause(cop0) & CAUSEF_IV)
+			arch->pc = KVM_GUEST_KSEG0 + 0x200;
+		else
+			arch->pc = KVM_GUEST_KSEG0 + 0x180;
+
+		clear_bit(priority, &vcpu->arch.pending_exceptions);
+	}
+
+	return allowed;
+}
+
+int
+kvm_mips_irq_clear_cb(struct kvm_vcpu *vcpu, unsigned int priority,
+		      uint32_t cause)
+{
+	return 1;
+}
+
+void kvm_mips_deliver_interrupts(struct kvm_vcpu *vcpu, uint32_t cause)
+{
+	unsigned long *pending = &vcpu->arch.pending_exceptions;
+	unsigned long *pending_clr = &vcpu->arch.pending_exceptions_clr;
+	unsigned int priority;
+
+	if (!(*pending) && !(*pending_clr))
+		return;
+
+	priority = __ffs(*pending_clr);
+	while (priority <= MIPS_EXC_MAX) {
+		if (kvm_mips_callbacks->irq_clear(vcpu, priority, cause)) {
+			if (!KVM_MIPS_IRQ_CLEAR_ALL_AT_ONCE)
+				break;
+		}
+
+		priority = find_next_bit(pending_clr,
+					 BITS_PER_BYTE * sizeof(*pending_clr),
+					 priority + 1);
+	}
+
+	priority = __ffs(*pending);
+	while (priority <= MIPS_EXC_MAX) {
+		if (kvm_mips_callbacks->irq_deliver(vcpu, priority, cause)) {
+			if (!KVM_MIPS_IRQ_DELIVER_ALL_AT_ONCE)
+				break;
+		}
+
+		priority = find_next_bit(pending,
+					 BITS_PER_BYTE * sizeof(*pending),
+					 priority + 1);
+	}
+
+}
+
+int kvm_mips_pending_timer(struct kvm_vcpu *vcpu)
+{
+	return test_bit(MIPS_EXC_INT_TIMER, &vcpu->arch.pending_exceptions);
+}
diff --git a/arch/mips/kvm/kvm_mips_int.h b/arch/mips/kvm/kvm_mips_int.h
new file mode 100644
index 0000000..20da7d2
--- /dev/null
+++ b/arch/mips/kvm/kvm_mips_int.h
@@ -0,0 +1,49 @@
+/*
+* This file is subject to the terms and conditions of the GNU General Public
+* License.  See the file "COPYING" in the main directory of this archive
+* for more details.
+*
+* KVM/MIPS: Interrupts
+* Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
+* Authors: Sanjay Lal <sanjayl@kymasys.com>
+*/
+
+/* MIPS Exception Priorities, exceptions (including interrupts) are queued up
+ * for the guest in the order specified by their priorities
+ */
+
+#define MIPS_EXC_RESET              0
+#define MIPS_EXC_SRESET             1
+#define MIPS_EXC_DEBUG_ST           2
+#define MIPS_EXC_DEBUG              3
+#define MIPS_EXC_DDB                4
+#define MIPS_EXC_NMI                5
+#define MIPS_EXC_MCHK               6
+#define MIPS_EXC_INT_TIMER          7
+#define MIPS_EXC_INT_IO             8
+#define MIPS_EXC_EXECUTE            9
+#define MIPS_EXC_INT_IPI_1          10
+#define MIPS_EXC_INT_IPI_2          11
+#define MIPS_EXC_MAX                12
+/* XXXSL More to follow */
+
+#define C_TI        (_ULCAST_(1) << 30)
+
+#define KVM_MIPS_IRQ_DELIVER_ALL_AT_ONCE (0)
+#define KVM_MIPS_IRQ_CLEAR_ALL_AT_ONCE   (0)
+
+void kvm_mips_queue_irq(struct kvm_vcpu *vcpu, uint32_t priority);
+void kvm_mips_dequeue_irq(struct kvm_vcpu *vcpu, uint32_t priority);
+int kvm_mips_pending_timer(struct kvm_vcpu *vcpu);
+
+void kvm_mips_queue_timer_int_cb(struct kvm_vcpu *vcpu);
+void kvm_mips_dequeue_timer_int_cb(struct kvm_vcpu *vcpu);
+void kvm_mips_queue_io_int_cb(struct kvm_vcpu *vcpu,
+			      struct kvm_mips_interrupt *irq);
+void kvm_mips_dequeue_io_int_cb(struct kvm_vcpu *vcpu,
+				struct kvm_mips_interrupt *irq);
+int kvm_mips_irq_deliver_cb(struct kvm_vcpu *vcpu, unsigned int priority,
+			    uint32_t cause);
+int kvm_mips_irq_clear_cb(struct kvm_vcpu *vcpu, unsigned int priority,
+			  uint32_t cause);
+void kvm_mips_deliver_interrupts(struct kvm_vcpu *vcpu, uint32_t cause);