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![Greg Kurz](/assets/img/avatar_default.png)
The XIVE VP is an internal structure which allow the XIVE interrupt controller to maintain the interrupt context state of vCPUs non dispatched on HW threads. When a guest is started, the XIVE KVM device allocates a block of XIVE VPs in OPAL, enough to accommodate the highest possible vCPU id KVM_MAX_VCPU_ID (16384) packed down to KVM_MAX_VCPUS (2048). With a guest's core stride of 8 and a threading mode of 1 (QEMU's default), a VM must run at least 256 vCPUs to actually need such a range of VPs. A POWER9 system has a limited XIVE VP space : 512k and KVM is currently wasting this HW resource with large VP allocations, especially since a typical VM likely runs with a lot less vCPUs. Make the size of the VP block configurable. Add an nr_servers field to the XIVE structure and a function to set it for this purpose. Split VP allocation out of the device create function. Since the VP block isn't used before the first vCPU connects to the XIVE KVM device, allocation is now performed by kvmppc_xive_connect_vcpu(). This gives the opportunity to set nr_servers in between: kvmppc_xive_create() / kvmppc_xive_native_create() . . kvmppc_xive_set_nr_servers() . . kvmppc_xive_connect_vcpu() / kvmppc_xive_native_connect_vcpu() The connect_vcpu() functions check that the vCPU id is below nr_servers and if it is the first vCPU they allocate the VP block. This is protected against a concurrent update of nr_servers by kvmppc_xive_set_nr_servers() with the xive->lock mutex. Also, the block is allocated once for the device lifetime: nr_servers should stay constant otherwise connect_vcpu() could generate a boggus VP id and likely crash OPAL. It is thus forbidden to update nr_servers once the block is allocated. If the VP allocation fail, return ENOSPC which seems more appropriate to report the depletion of system wide HW resource than ENOMEM or ENXIO. A VM using a stride of 8 and 1 thread per core with 32 vCPUs would hence only need 256 VPs instead of 2048. If the stride is set to match the number of threads per core, this goes further down to 32. This will be exposed to userspace by a subsequent patch. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
306 lines
8.1 KiB
C
306 lines
8.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright 2017 Benjamin Herrenschmidt, IBM Corporation
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*/
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#ifndef _KVM_PPC_BOOK3S_XIVE_H
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#define _KVM_PPC_BOOK3S_XIVE_H
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#ifdef CONFIG_KVM_XICS
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#include "book3s_xics.h"
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/*
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* The XIVE Interrupt source numbers are within the range 0 to
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* KVMPPC_XICS_NR_IRQS.
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*/
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#define KVMPPC_XIVE_FIRST_IRQ 0
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#define KVMPPC_XIVE_NR_IRQS KVMPPC_XICS_NR_IRQS
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/*
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* State for one guest irq source.
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*
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* For each guest source we allocate a HW interrupt in the XIVE
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* which we use for all SW triggers. It will be unused for
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* pass-through but it's easier to keep around as the same
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* guest interrupt can alternatively be emulated or pass-through
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* if a physical device is hot unplugged and replaced with an
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* emulated one.
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*
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* This state structure is very similar to the XICS one with
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* additional XIVE specific tracking.
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*/
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struct kvmppc_xive_irq_state {
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bool valid; /* Interrupt entry is valid */
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u32 number; /* Guest IRQ number */
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u32 ipi_number; /* XIVE IPI HW number */
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struct xive_irq_data ipi_data; /* XIVE IPI associated data */
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u32 pt_number; /* XIVE Pass-through number if any */
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struct xive_irq_data *pt_data; /* XIVE Pass-through associated data */
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/* Targetting as set by guest */
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u8 guest_priority; /* Guest set priority */
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u8 saved_priority; /* Saved priority when masking */
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/* Actual targetting */
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u32 act_server; /* Actual server */
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u8 act_priority; /* Actual priority */
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/* Various state bits */
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bool in_eoi; /* Synchronize with H_EOI */
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bool old_p; /* P bit state when masking */
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bool old_q; /* Q bit state when masking */
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bool lsi; /* level-sensitive interrupt */
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bool asserted; /* Only for emulated LSI: current state */
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/* Saved for migration state */
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bool in_queue;
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bool saved_p;
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bool saved_q;
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u8 saved_scan_prio;
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/* Xive native */
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u32 eisn; /* Guest Effective IRQ number */
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};
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/* Select the "right" interrupt (IPI vs. passthrough) */
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static inline void kvmppc_xive_select_irq(struct kvmppc_xive_irq_state *state,
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u32 *out_hw_irq,
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struct xive_irq_data **out_xd)
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{
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if (state->pt_number) {
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if (out_hw_irq)
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*out_hw_irq = state->pt_number;
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if (out_xd)
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*out_xd = state->pt_data;
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} else {
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if (out_hw_irq)
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*out_hw_irq = state->ipi_number;
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if (out_xd)
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*out_xd = &state->ipi_data;
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}
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}
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/*
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* This corresponds to an "ICS" in XICS terminology, we use it
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* as a mean to break up source information into multiple structures.
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*/
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struct kvmppc_xive_src_block {
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arch_spinlock_t lock;
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u16 id;
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struct kvmppc_xive_irq_state irq_state[KVMPPC_XICS_IRQ_PER_ICS];
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};
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struct kvmppc_xive;
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struct kvmppc_xive_ops {
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int (*reset_mapped)(struct kvm *kvm, unsigned long guest_irq);
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};
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struct kvmppc_xive {
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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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/* VP block associated with the VM */
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u32 vp_base;
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/* Blocks of sources */
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struct kvmppc_xive_src_block *src_blocks[KVMPPC_XICS_MAX_ICS_ID + 1];
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u32 max_sbid;
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/*
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* For state save, we lazily scan the queues on the first interrupt
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* being migrated. We don't have a clean way to reset that flags
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* so we keep track of the number of valid sources and how many of
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* them were migrated so we can reset when all of them have been
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* processed.
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*/
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u32 src_count;
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u32 saved_src_count;
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/*
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* Some irqs are delayed on restore until the source is created,
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* keep track here of how many of them
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*/
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u32 delayed_irqs;
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/* Which queues (priorities) are in use by the guest */
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u8 qmap;
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/* Queue orders */
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u32 q_order;
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u32 q_page_order;
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/* Flags */
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u8 single_escalation;
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/* Number of entries in the VP block */
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u32 nr_servers;
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struct kvmppc_xive_ops *ops;
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struct address_space *mapping;
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struct mutex mapping_lock;
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struct mutex lock;
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};
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#define KVMPPC_XIVE_Q_COUNT 8
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struct kvmppc_xive_vcpu {
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struct kvmppc_xive *xive;
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struct kvm_vcpu *vcpu;
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bool valid;
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/* Server number. This is the HW CPU ID from a guest perspective */
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u32 server_num;
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/*
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* HW VP corresponding to this VCPU. This is the base of the VP
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* block plus the server number.
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*/
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u32 vp_id;
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u32 vp_chip_id;
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u32 vp_cam;
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/* IPI used for sending ... IPIs */
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u32 vp_ipi;
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struct xive_irq_data vp_ipi_data;
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/* Local emulation state */
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uint8_t cppr; /* guest CPPR */
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uint8_t hw_cppr;/* Hardware CPPR */
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uint8_t mfrr;
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uint8_t pending;
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/* Each VP has 8 queues though we only provision some */
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struct xive_q queues[KVMPPC_XIVE_Q_COUNT];
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u32 esc_virq[KVMPPC_XIVE_Q_COUNT];
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char *esc_virq_names[KVMPPC_XIVE_Q_COUNT];
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/* Stash a delayed irq on restore from migration (see set_icp) */
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u32 delayed_irq;
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/* Stats */
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u64 stat_rm_h_xirr;
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u64 stat_rm_h_ipoll;
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u64 stat_rm_h_cppr;
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u64 stat_rm_h_eoi;
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u64 stat_rm_h_ipi;
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u64 stat_vm_h_xirr;
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u64 stat_vm_h_ipoll;
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u64 stat_vm_h_cppr;
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u64 stat_vm_h_eoi;
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u64 stat_vm_h_ipi;
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};
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static inline struct kvm_vcpu *kvmppc_xive_find_server(struct kvm *kvm, 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.xive_vcpu && nr == vcpu->arch.xive_vcpu->server_num)
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return vcpu;
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}
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return NULL;
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}
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static inline struct kvmppc_xive_src_block *kvmppc_xive_find_source(struct kvmppc_xive *xive,
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u32 irq, u16 *source)
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{
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u32 bid = irq >> KVMPPC_XICS_ICS_SHIFT;
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u16 src = irq & KVMPPC_XICS_SRC_MASK;
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if (source)
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*source = src;
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if (bid > KVMPPC_XICS_MAX_ICS_ID)
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return NULL;
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return xive->src_blocks[bid];
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}
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static inline u32 kvmppc_xive_vp(struct kvmppc_xive *xive, u32 server)
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{
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return xive->vp_base + kvmppc_pack_vcpu_id(xive->kvm, server);
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}
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static inline bool kvmppc_xive_vp_in_use(struct kvm *kvm, u32 vp_id)
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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.xive_vcpu && vp_id == vcpu->arch.xive_vcpu->vp_id)
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return true;
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}
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return false;
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}
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/*
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* Mapping between guest priorities and host priorities
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* is as follow.
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*
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* Guest request for 0...6 are honored. Guest request for anything
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* higher results in a priority of 6 being applied.
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*
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* Similar mapping is done for CPPR values
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*/
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static inline u8 xive_prio_from_guest(u8 prio)
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{
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if (prio == 0xff || prio < 6)
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return prio;
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return 6;
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}
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static inline u8 xive_prio_to_guest(u8 prio)
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{
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return prio;
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}
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static inline u32 __xive_read_eq(__be32 *qpage, u32 msk, u32 *idx, u32 *toggle)
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{
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u32 cur;
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if (!qpage)
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return 0;
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cur = be32_to_cpup(qpage + *idx);
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if ((cur >> 31) == *toggle)
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return 0;
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*idx = (*idx + 1) & msk;
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if (*idx == 0)
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(*toggle) ^= 1;
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return cur & 0x7fffffff;
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}
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extern unsigned long xive_rm_h_xirr(struct kvm_vcpu *vcpu);
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extern unsigned long xive_rm_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server);
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extern int xive_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
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unsigned long mfrr);
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extern int xive_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr);
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extern int xive_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr);
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extern unsigned long (*__xive_vm_h_xirr)(struct kvm_vcpu *vcpu);
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extern unsigned long (*__xive_vm_h_ipoll)(struct kvm_vcpu *vcpu, unsigned long server);
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extern int (*__xive_vm_h_ipi)(struct kvm_vcpu *vcpu, unsigned long server,
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unsigned long mfrr);
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extern int (*__xive_vm_h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr);
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extern int (*__xive_vm_h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr);
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/*
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* Common Xive routines for XICS-over-XIVE and XIVE native
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*/
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void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu);
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int kvmppc_xive_debug_show_queues(struct seq_file *m, struct kvm_vcpu *vcpu);
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struct kvmppc_xive_src_block *kvmppc_xive_create_src_block(
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struct kvmppc_xive *xive, int irq);
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void kvmppc_xive_free_sources(struct kvmppc_xive_src_block *sb);
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int kvmppc_xive_select_target(struct kvm *kvm, u32 *server, u8 prio);
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int kvmppc_xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio,
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bool single_escalation);
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struct kvmppc_xive *kvmppc_xive_get_device(struct kvm *kvm, u32 type);
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void xive_cleanup_single_escalation(struct kvm_vcpu *vcpu,
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struct kvmppc_xive_vcpu *xc, int irq);
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int kvmppc_xive_compute_vp_id(struct kvmppc_xive *xive, u32 cpu, u32 *vp);
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int kvmppc_xive_set_nr_servers(struct kvmppc_xive *xive, u64 addr);
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#endif /* CONFIG_KVM_XICS */
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#endif /* _KVM_PPC_BOOK3S_XICS_H */
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