KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller

This patch makes KVM capable of using the XIVE interrupt controller
to provide the standard PAPR "XICS" style hypercalls. It is necessary
for proper operations when the host uses XIVE natively.

This has been lightly tested on an actual system, including PCI
pass-through with a TG3 device.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Cleanup pr_xxx(), unsplit pr_xxx() strings, etc., fix build
 failures by adding KVM_XIVE which depends on KVM_XICS and XIVE, and
 adding empty stubs for the kvm_xive_xxx() routines, fixup subject,
 integrate fixes from Paul for building PR=y HV=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 256 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_xive.h b/arch/powerpc/kvm/book3s_xive.h
new file mode 100644
index 000000000000..5938f7644dc1
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_xive.h
@@ -0,0 +1,256 @@
+/*
+ * Copyright 2017 Benjamin Herrenschmidt, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _KVM_PPC_BOOK3S_XIVE_H
+#define _KVM_PPC_BOOK3S_XIVE_H
+
+#ifdef CONFIG_KVM_XICS
+#include "book3s_xics.h"
+
+/*
+ * State for one guest irq source.
+ *
+ * For each guest source we allocate a HW interrupt in the XIVE
+ * which we use for all SW triggers. It will be unused for
+ * pass-through but it's easier to keep around as the same
+ * guest interrupt can alternatively be emulated or pass-through
+ * if a physical device is hot unplugged and replaced with an
+ * emulated one.
+ *
+ * This state structure is very similar to the XICS one with
+ * additional XIVE specific tracking.
+ */
+struct kvmppc_xive_irq_state {
+	bool valid;			/* Interrupt entry is valid */
+
+	u32 number;			/* Guest IRQ number */
+	u32 ipi_number;			/* XIVE IPI HW number */
+	struct xive_irq_data ipi_data;	/* XIVE IPI associated data */
+	u32 pt_number;			/* XIVE Pass-through number if any */
+	struct xive_irq_data *pt_data;	/* XIVE Pass-through associated data */
+
+	/* Targetting as set by guest */
+	u32 guest_server;		/* Current guest selected target */
+	u8 guest_priority;		/* Guest set priority */
+	u8 saved_priority;		/* Saved priority when masking */
+
+	/* Actual targetting */
+	u32 act_server;			/* Actual server */
+	u8 act_priority;		/* Actual priority */
+
+	/* Various state bits */
+	bool in_eoi;			/* Synchronize with H_EOI */
+	bool old_p;			/* P bit state when masking */
+	bool old_q;			/* Q bit state when masking */
+	bool lsi;			/* level-sensitive interrupt */
+	bool asserted;			/* Only for emulated LSI: current state */
+
+	/* Saved for migration state */
+	bool in_queue;
+	bool saved_p;
+	bool saved_q;
+	u8 saved_scan_prio;
+};
+
+/* Select the "right" interrupt (IPI vs. passthrough) */
+static inline void kvmppc_xive_select_irq(struct kvmppc_xive_irq_state *state,
+					  u32 *out_hw_irq,
+					  struct xive_irq_data **out_xd)
+{
+	if (state->pt_number) {
+		if (out_hw_irq)
+			*out_hw_irq = state->pt_number;
+		if (out_xd)
+			*out_xd = state->pt_data;
+	} else {
+		if (out_hw_irq)
+			*out_hw_irq = state->ipi_number;
+		if (out_xd)
+			*out_xd = &state->ipi_data;
+	}
+}
+
+/*
+ * This corresponds to an "ICS" in XICS terminology, we use it
+ * as a mean to break up source information into multiple structures.
+ */
+struct kvmppc_xive_src_block {
+	arch_spinlock_t lock;
+	u16 id;
+	struct kvmppc_xive_irq_state irq_state[KVMPPC_XICS_IRQ_PER_ICS];
+};
+
+
+struct kvmppc_xive {
+	struct kvm *kvm;
+	struct kvm_device *dev;
+	struct dentry *dentry;
+
+	/* VP block associated with the VM */
+	u32	vp_base;
+
+	/* Blocks of sources */
+	struct kvmppc_xive_src_block *src_blocks[KVMPPC_XICS_MAX_ICS_ID + 1];
+	u32	max_sbid;
+
+	/*
+	 * For state save, we lazily scan the queues on the first interrupt
+	 * being migrated. We don't have a clean way to reset that flags
+	 * so we keep track of the number of valid sources and how many of
+	 * them were migrated so we can reset when all of them have been
+	 * processed.
+	 */
+	u32	src_count;
+	u32	saved_src_count;
+
+	/*
+	 * Some irqs are delayed on restore until the source is created,
+	 * keep track here of how many of them
+	 */
+	u32	delayed_irqs;
+
+	/* Which queues (priorities) are in use by the guest */
+	u8	qmap;
+
+	/* Queue orders */
+	u32	q_order;
+	u32	q_page_order;
+
+};
+
+#define KVMPPC_XIVE_Q_COUNT	8
+
+struct kvmppc_xive_vcpu {
+	struct kvmppc_xive	*xive;
+	struct kvm_vcpu		*vcpu;
+	bool			valid;
+
+	/* Server number. This is the HW CPU ID from a guest perspective */
+	u32			server_num;
+
+	/*
+	 * HW VP corresponding to this VCPU. This is the base of the VP
+	 * block plus the server number.
+	 */
+	u32			vp_id;
+	u32			vp_chip_id;
+	u32			vp_cam;
+
+	/* IPI used for sending ... IPIs */
+	u32			vp_ipi;
+	struct xive_irq_data	vp_ipi_data;
+
+	/* Local emulation state */
+	uint8_t			cppr;	/* guest CPPR */
+	uint8_t			hw_cppr;/* Hardware CPPR */
+	uint8_t			mfrr;
+	uint8_t			pending;
+
+	/* Each VP has 8 queues though we only provision some */
+	struct xive_q		queues[KVMPPC_XIVE_Q_COUNT];
+	u32			esc_virq[KVMPPC_XIVE_Q_COUNT];
+	char			*esc_virq_names[KVMPPC_XIVE_Q_COUNT];
+
+	/* Stash a delayed irq on restore from migration (see set_icp) */
+	u32			delayed_irq;
+
+	/* Stats */
+	u64			stat_rm_h_xirr;
+	u64			stat_rm_h_ipoll;
+	u64			stat_rm_h_cppr;
+	u64			stat_rm_h_eoi;
+	u64			stat_rm_h_ipi;
+	u64			stat_vm_h_xirr;
+	u64			stat_vm_h_ipoll;
+	u64			stat_vm_h_cppr;
+	u64			stat_vm_h_eoi;
+	u64			stat_vm_h_ipi;
+};
+
+static inline struct kvm_vcpu *kvmppc_xive_find_server(struct kvm *kvm, u32 nr)
+{
+	struct kvm_vcpu *vcpu = NULL;
+	int i;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		if (vcpu->arch.xive_vcpu && nr == vcpu->arch.xive_vcpu->server_num)
+			return vcpu;
+	}
+	return NULL;
+}
+
+static inline struct kvmppc_xive_src_block *kvmppc_xive_find_source(struct kvmppc_xive *xive,
+		u32 irq, u16 *source)
+{
+	u32 bid = irq >> KVMPPC_XICS_ICS_SHIFT;
+	u16 src = irq & KVMPPC_XICS_SRC_MASK;
+
+	if (source)
+		*source = src;
+	if (bid > KVMPPC_XICS_MAX_ICS_ID)
+		return NULL;
+	return xive->src_blocks[bid];
+}
+
+/*
+ * Mapping between guest priorities and host priorities
+ * is as follow.
+ *
+ * Guest request for 0...6 are honored. Guest request for anything
+ * higher results in a priority of 7 being applied.
+ *
+ * However, when XIRR is returned via H_XIRR, 7 is translated to 0xb
+ * in order to match AIX expectations
+ *
+ * Similar mapping is done for CPPR values
+ */
+static inline u8 xive_prio_from_guest(u8 prio)
+{
+	if (prio == 0xff || prio < 8)
+		return prio;
+	return 7;
+}
+
+static inline u8 xive_prio_to_guest(u8 prio)
+{
+	if (prio == 0xff || prio < 7)
+		return prio;
+	return 0xb;
+}
+
+static inline u32 __xive_read_eq(__be32 *qpage, u32 msk, u32 *idx, u32 *toggle)
+{
+	u32 cur;
+
+	if (!qpage)
+		return 0;
+	cur = be32_to_cpup(qpage + *idx);
+	if ((cur >> 31) == *toggle)
+		return 0;
+	*idx = (*idx + 1) & msk;
+	if (*idx == 0)
+		(*toggle) ^= 1;
+	return cur & 0x7fffffff;
+}
+
+extern unsigned long xive_rm_h_xirr(struct kvm_vcpu *vcpu);
+extern unsigned long xive_rm_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server);
+extern int xive_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
+			 unsigned long mfrr);
+extern int xive_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr);
+extern int xive_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr);
+
+extern unsigned long (*__xive_vm_h_xirr)(struct kvm_vcpu *vcpu);
+extern unsigned long (*__xive_vm_h_ipoll)(struct kvm_vcpu *vcpu, unsigned long server);
+extern int (*__xive_vm_h_ipi)(struct kvm_vcpu *vcpu, unsigned long server,
+			      unsigned long mfrr);
+extern int (*__xive_vm_h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr);
+extern int (*__xive_vm_h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr);
+
+#endif /* CONFIG_KVM_XICS */
+#endif /* _KVM_PPC_BOOK3S_XICS_H */