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5b88cda665
This fixes some inaccuracies in the state machine for the virtualized ICP when implementing the H_IPI hcall (Set_MFFR and related states): 1. The old code wipes out any pending interrupts when the new MFRR is more favored than the CPPR but less favored than a pending interrupt (by always modifying xisr and the pending_pri). This can cause us to lose a pending external interrupt. The correct code here is to only modify the pending_pri and xisr in the ICP if the MFRR is equal to or more favored than the current pending pri (since in this case, it is guaranteed that that there cannot be a pending external interrupt). The code changes are required in both kvmppc_rm_h_ipi and kvmppc_h_ipi. 2. Again, in both kvmppc_rm_h_ipi and kvmppc_h_ipi, there is a check for whether MFRR is being made less favored AND further if new MFFR is also less favored than the current CPPR, we check for any resends pending in the ICP. These checks look like they are designed to cover the case where if the MFRR is being made less favored, we opportunistically trigger a resend of any interrupts that had been previously rejected. Although, this is not a state described by PAPR, this is an action we actually need to do especially if the CPPR is already at 0xFF. Because in this case, the resend bit will stay on until another ICP state change which may be a long time coming and the interrupt stays pending until then. The current code which checks for MFRR < CPPR is broken when CPPR is 0xFF since it will not get triggered in that case. Ideally, we would want to do a resend only if prio(pending_interrupt) < mfrr && prio(pending_interrupt) < cppr where pending interrupt is the one that was rejected. But we don't have the priority of the pending interrupt state saved, so we simply trigger a resend whenever the MFRR is made less favored. 3. In kvmppc_rm_h_ipi, where we save state to pass resends to the virtual mode, we also need to save the ICP whose need_resend we reset since this does not need to be my ICP (vcpu->arch.icp) as is incorrectly assumed by the current code. A new field rm_resend_icp is added to the kvmppc_icp structure for this purpose. Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
133 lines
3.1 KiB
C
133 lines
3.1 KiB
C
/*
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* Copyright 2012 Michael Ellerman, IBM Corporation.
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* Copyright 2012 Benjamin Herrenschmidt, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*/
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#ifndef _KVM_PPC_BOOK3S_XICS_H
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#define _KVM_PPC_BOOK3S_XICS_H
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/*
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* We use a two-level tree to store interrupt source information.
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* There are up to 1024 ICS nodes, each of which can represent
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* 1024 sources.
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*/
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#define KVMPPC_XICS_MAX_ICS_ID 1023
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#define KVMPPC_XICS_ICS_SHIFT 10
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#define KVMPPC_XICS_IRQ_PER_ICS (1 << KVMPPC_XICS_ICS_SHIFT)
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#define KVMPPC_XICS_SRC_MASK (KVMPPC_XICS_IRQ_PER_ICS - 1)
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/*
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* Interrupt source numbers below this are reserved, for example
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* 0 is "no interrupt", and 2 is used for IPIs.
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*/
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#define KVMPPC_XICS_FIRST_IRQ 16
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#define KVMPPC_XICS_NR_IRQS ((KVMPPC_XICS_MAX_ICS_ID + 1) * \
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KVMPPC_XICS_IRQ_PER_ICS)
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/* Priority value to use for disabling an interrupt */
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#define MASKED 0xff
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/* State for one irq source */
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struct ics_irq_state {
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u32 number;
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u32 server;
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u8 priority;
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u8 saved_priority;
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u8 resend;
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u8 masked_pending;
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u8 asserted; /* Only for LSI */
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u8 exists;
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};
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/* Atomic ICP state, updated with a single compare & swap */
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union kvmppc_icp_state {
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unsigned long raw;
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struct {
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u8 out_ee:1;
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u8 need_resend:1;
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u8 cppr;
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u8 mfrr;
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u8 pending_pri;
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u32 xisr;
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};
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};
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/* One bit per ICS */
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#define ICP_RESEND_MAP_SIZE (KVMPPC_XICS_MAX_ICS_ID / BITS_PER_LONG + 1)
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struct kvmppc_icp {
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struct kvm_vcpu *vcpu;
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unsigned long server_num;
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union kvmppc_icp_state state;
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unsigned long resend_map[ICP_RESEND_MAP_SIZE];
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/* Real mode might find something too hard, here's the action
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* it might request from virtual mode
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*/
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#define XICS_RM_KICK_VCPU 0x1
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#define XICS_RM_CHECK_RESEND 0x2
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#define XICS_RM_REJECT 0x4
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#define XICS_RM_NOTIFY_EOI 0x8
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u32 rm_action;
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struct kvm_vcpu *rm_kick_target;
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struct kvmppc_icp *rm_resend_icp;
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u32 rm_reject;
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u32 rm_eoied_irq;
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/* Debug stuff for real mode */
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union kvmppc_icp_state rm_dbgstate;
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struct kvm_vcpu *rm_dbgtgt;
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};
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struct kvmppc_ics {
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struct mutex lock;
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u16 icsid;
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struct ics_irq_state irq_state[KVMPPC_XICS_IRQ_PER_ICS];
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};
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struct kvmppc_xics {
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struct kvm *kvm;
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struct kvm_device *dev;
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struct dentry *dentry;
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u32 max_icsid;
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bool real_mode;
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bool real_mode_dbg;
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struct kvmppc_ics *ics[KVMPPC_XICS_MAX_ICS_ID + 1];
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};
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static inline struct kvmppc_icp *kvmppc_xics_find_server(struct kvm *kvm,
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u32 nr)
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{
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struct kvm_vcpu *vcpu = NULL;
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int i;
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kvm_for_each_vcpu(i, vcpu, kvm) {
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if (vcpu->arch.icp && nr == vcpu->arch.icp->server_num)
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return vcpu->arch.icp;
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}
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return NULL;
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}
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static inline struct kvmppc_ics *kvmppc_xics_find_ics(struct kvmppc_xics *xics,
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u32 irq, u16 *source)
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{
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u32 icsid = irq >> KVMPPC_XICS_ICS_SHIFT;
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u16 src = irq & KVMPPC_XICS_SRC_MASK;
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struct kvmppc_ics *ics;
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if (source)
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*source = src;
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if (icsid > KVMPPC_XICS_MAX_ICS_ID)
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return NULL;
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ics = xics->ics[icsid];
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if (!ics)
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return NULL;
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return ics;
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}
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#endif /* _KVM_PPC_BOOK3S_XICS_H */
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