linux/arch/powerpc/kvm/book3s_xics.h
Paul Mackerras b1a4286b8f KVM: PPC: Book3S HV: Re-enable XICS fast path for irqfd-generated interrupts
Commit c9a5eccac1 ("kvm/eventfd: add arch-specific set_irq",
2015-10-16) added the possibility for architecture-specific code
to handle the generation of virtual interrupts in atomic context
where possible, without having to schedule a work function.

Since we can easily generate virtual interrupts on XICS without
having to do anything worse than take a spinlock, we define a
kvm_arch_set_irq_inatomic() for XICS.  We also remove kvm_set_msi()
since it is not used any more.

The one slightly tricky thing is that with the new interface, we
don't get told whether the interrupt is an MSI (or other edge
sensitive interrupt) vs. level-sensitive.  The difference as far
as interrupt generation is concerned is that for LSIs we have to
set the asserted flag so it will continue to fire until it is
explicitly cleared.

In fact the XICS code gets told which interrupts are LSIs by userspace
when it configures the interrupt via the KVM_DEV_XICS_GRP_SOURCES
attribute group on the XICS device.  To store this information, we add
a new "lsi" field to struct ics_irq_state.  With that we can also do a
better job of returning accurate values when reading the attribute
group.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2016-05-12 16:40:55 +10:00

146 lines
3.4 KiB
C

/*
* Copyright 2012 Michael Ellerman, IBM Corporation.
* Copyright 2012 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_XICS_H
#define _KVM_PPC_BOOK3S_XICS_H
/*
* We use a two-level tree to store interrupt source information.
* There are up to 1024 ICS nodes, each of which can represent
* 1024 sources.
*/
#define KVMPPC_XICS_MAX_ICS_ID 1023
#define KVMPPC_XICS_ICS_SHIFT 10
#define KVMPPC_XICS_IRQ_PER_ICS (1 << KVMPPC_XICS_ICS_SHIFT)
#define KVMPPC_XICS_SRC_MASK (KVMPPC_XICS_IRQ_PER_ICS - 1)
/*
* Interrupt source numbers below this are reserved, for example
* 0 is "no interrupt", and 2 is used for IPIs.
*/
#define KVMPPC_XICS_FIRST_IRQ 16
#define KVMPPC_XICS_NR_IRQS ((KVMPPC_XICS_MAX_ICS_ID + 1) * \
KVMPPC_XICS_IRQ_PER_ICS)
/* Priority value to use for disabling an interrupt */
#define MASKED 0xff
/* State for one irq source */
struct ics_irq_state {
u32 number;
u32 server;
u8 priority;
u8 saved_priority;
u8 resend;
u8 masked_pending;
u8 lsi; /* level-sensitive interrupt */
u8 asserted; /* Only for LSI */
u8 exists;
};
/* Atomic ICP state, updated with a single compare & swap */
union kvmppc_icp_state {
unsigned long raw;
struct {
u8 out_ee:1;
u8 need_resend:1;
u8 cppr;
u8 mfrr;
u8 pending_pri;
u32 xisr;
};
};
/* One bit per ICS */
#define ICP_RESEND_MAP_SIZE (KVMPPC_XICS_MAX_ICS_ID / BITS_PER_LONG + 1)
struct kvmppc_icp {
struct kvm_vcpu *vcpu;
unsigned long server_num;
union kvmppc_icp_state state;
unsigned long resend_map[ICP_RESEND_MAP_SIZE];
/* Real mode might find something too hard, here's the action
* it might request from virtual mode
*/
#define XICS_RM_KICK_VCPU 0x1
#define XICS_RM_CHECK_RESEND 0x2
#define XICS_RM_REJECT 0x4
#define XICS_RM_NOTIFY_EOI 0x8
u32 rm_action;
struct kvm_vcpu *rm_kick_target;
struct kvmppc_icp *rm_resend_icp;
u32 rm_reject;
u32 rm_eoied_irq;
/* Counters for each reason we exited real mode */
unsigned long n_rm_kick_vcpu;
unsigned long n_rm_check_resend;
unsigned long n_rm_reject;
unsigned long n_rm_notify_eoi;
/* Counters for handling ICP processing in real mode */
unsigned long n_check_resend;
unsigned long n_reject;
/* Debug stuff for real mode */
union kvmppc_icp_state rm_dbgstate;
struct kvm_vcpu *rm_dbgtgt;
};
struct kvmppc_ics {
arch_spinlock_t lock;
u16 icsid;
struct ics_irq_state irq_state[KVMPPC_XICS_IRQ_PER_ICS];
};
struct kvmppc_xics {
struct kvm *kvm;
struct kvm_device *dev;
struct dentry *dentry;
u32 max_icsid;
bool real_mode;
bool real_mode_dbg;
u32 err_noics;
u32 err_noicp;
struct kvmppc_ics *ics[KVMPPC_XICS_MAX_ICS_ID + 1];
};
static inline struct kvmppc_icp *kvmppc_xics_find_server(struct kvm *kvm,
u32 nr)
{
struct kvm_vcpu *vcpu = NULL;
int i;
kvm_for_each_vcpu(i, vcpu, kvm) {
if (vcpu->arch.icp && nr == vcpu->arch.icp->server_num)
return vcpu->arch.icp;
}
return NULL;
}
static inline struct kvmppc_ics *kvmppc_xics_find_ics(struct kvmppc_xics *xics,
u32 irq, u16 *source)
{
u32 icsid = irq >> KVMPPC_XICS_ICS_SHIFT;
u16 src = irq & KVMPPC_XICS_SRC_MASK;
struct kvmppc_ics *ics;
if (source)
*source = src;
if (icsid > KVMPPC_XICS_MAX_ICS_ID)
return NULL;
ics = xics->ics[icsid];
if (!ics)
return NULL;
return ics;
}
#endif /* _KVM_PPC_BOOK3S_XICS_H */