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    Subject[PATCH 10/45] KVM: s390: interprocessor communication via sigp
    Date
    From: Carsten Otte <cotte@de.ibm.com>

    From: Christian Borntraeger <borntraeger@de.ibm.com>

    This patch introduces in-kernel handling of _some_ sigp interprocessor
    signals (similar to ipi).
    kvm_s390_handle_sigp() decodes the sigp instruction and calls individual
    handlers depending on the operation requested:
    - sigp sense tries to retrieve information such as existence or running state
    of the remote cpu
    - sigp emergency sends an external interrupt to the remove cpu
    - sigp stop stops a remove cpu
    - sigp stop store status stops a remote cpu, and stores its entire internal
    state to the cpus lowcore
    - sigp set arch sets the architecture mode of the remote cpu. setting to
    ESAME (s390x 64bit) is accepted, setting to ESA/S390 (s390, 31 or 24 bit) is
    denied, all others are passed to userland
    - sigp set prefix sets the prefix register of a remote cpu

    For implementation of this, the stop intercept indication starts to get reused
    on purpose: a set of action bits defines what to do once a cpu gets stopped:
    ACTION_STOP_ON_STOP really stops the cpu when a stop intercept is recognized
    ACTION_STORE_ON_STOP stores the cpu status to lowcore when a stop intercept is
    recognized

    Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: Carsten Otte <cotte@de.ibm.com>
    Signed-off-by: Carsten Otte <cotte@de.ibm.com>
    Signed-off-by: Avi Kivity <avi@qumranet.com>
    ---
    arch/s390/kvm/Makefile | 2 +-
    arch/s390/kvm/intercept.c | 22 +++-
    arch/s390/kvm/kvm-s390.c | 7 +
    arch/s390/kvm/kvm-s390.h | 7 +
    arch/s390/kvm/sigp.c | 288 +++++++++++++++++++++++++++++++++++++++++++
    include/asm-s390/kvm_host.h | 12 ++
    6 files changed, 335 insertions(+), 3 deletions(-)
    create mode 100644 arch/s390/kvm/sigp.c

    diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
    index 82dde1e..f3bf11a 100644
    --- a/arch/s390/kvm/Makefile
    +++ b/arch/s390/kvm/Makefile
    @@ -10,5 +10,5 @@ common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o)

    EXTRA_CFLAGS += -Ivirt/kvm -Iarch/s390/kvm

    -kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o
    +kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o sigp.o
    obj-$(CONFIG_KVM) += kvm.o
    diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
    index 7a20d63..9f0d8b2 100644
    --- a/arch/s390/kvm/intercept.c
    +++ b/arch/s390/kvm/intercept.c
    @@ -95,6 +95,7 @@ static int handle_lctl(struct kvm_vcpu *vcpu)
    }

    static intercept_handler_t instruction_handlers[256] = {
    + [0xae] = kvm_s390_handle_sigp,
    [0xb2] = kvm_s390_handle_priv,
    [0xb7] = handle_lctl,
    [0xeb] = handle_lctg,
    @@ -117,10 +118,27 @@ static int handle_noop(struct kvm_vcpu *vcpu)

    static int handle_stop(struct kvm_vcpu *vcpu)
    {
    + int rc;
    +
    vcpu->stat.exit_stop_request++;
    - VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
    atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
    - return -ENOTSUPP;
    + spin_lock_bh(&vcpu->arch.local_int.lock);
    + if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
    + vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
    + rc = __kvm_s390_vcpu_store_status(vcpu,
    + KVM_S390_STORE_STATUS_NOADDR);
    + if (rc >= 0)
    + rc = -ENOTSUPP;
    + }
    +
    + if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
    + vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
    + VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
    + rc = -ENOTSUPP;
    + } else
    + rc = 0;
    + spin_unlock_bh(&vcpu->arch.local_int.lock);
    + return rc;
    }

    static int handle_validity(struct kvm_vcpu *vcpu)
    diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
    index 5a17176..c632180 100644
    --- a/arch/s390/kvm/kvm-s390.c
    +++ b/arch/s390/kvm/kvm-s390.c
    @@ -57,6 +57,12 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
    { "instruction_chsc", VCPU_STAT(instruction_chsc) },
    { "instruction_stsi", VCPU_STAT(instruction_stsi) },
    { "instruction_stfl", VCPU_STAT(instruction_stfl) },
    + { "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
    + { "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },
    + { "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },
    + { "instruction_sigp_set_arch", VCPU_STAT(instruction_sigp_arch) },
    + { "instruction_sigp_set_prefix", VCPU_STAT(instruction_sigp_prefix) },
    + { "instruction_sigp_restart", VCPU_STAT(instruction_sigp_restart) },
    { NULL }
    };

    @@ -287,6 +293,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
    spin_lock_bh(&kvm->arch.float_int.lock);
    kvm->arch.float_int.local_int[id] = &vcpu->arch.local_int;
    init_waitqueue_head(&vcpu->arch.local_int.wq);
    + vcpu->arch.local_int.cpuflags = &vcpu->arch.sie_block->cpuflags;
    spin_unlock_bh(&kvm->arch.float_int.lock);

    rc = kvm_vcpu_init(vcpu, kvm, id);
    diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
    index 50f96b3..e6e5756 100644
    --- a/arch/s390/kvm/kvm-s390.h
    +++ b/arch/s390/kvm/kvm-s390.h
    @@ -51,4 +51,11 @@ int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);

    /* implemented in priv.c */
    int kvm_s390_handle_priv(struct kvm_vcpu *vcpu);
    +
    +/* implemented in sigp.c */
    +int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);
    +
    +/* implemented in kvm-s390.c */
    +int __kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu,
    + unsigned long addr);
    #endif
    diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
    new file mode 100644
    index 0000000..0a236ac
    --- /dev/null
    +++ b/arch/s390/kvm/sigp.c
    @@ -0,0 +1,288 @@
    +/*
    + * sigp.c - handlinge interprocessor communication
    + *
    + * Copyright IBM Corp. 2008
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License (version 2 only)
    + * as published by the Free Software Foundation.
    + *
    + * Author(s): Carsten Otte <cotte@de.ibm.com>
    + * Christian Borntraeger <borntraeger@de.ibm.com>
    + */
    +
    +#include <linux/kvm.h>
    +#include <linux/kvm_host.h>
    +#include "gaccess.h"
    +#include "kvm-s390.h"
    +
    +/* sigp order codes */
    +#define SIGP_SENSE 0x01
    +#define SIGP_EXTERNAL_CALL 0x02
    +#define SIGP_EMERGENCY 0x03
    +#define SIGP_START 0x04
    +#define SIGP_STOP 0x05
    +#define SIGP_RESTART 0x06
    +#define SIGP_STOP_STORE_STATUS 0x09
    +#define SIGP_INITIAL_CPU_RESET 0x0b
    +#define SIGP_CPU_RESET 0x0c
    +#define SIGP_SET_PREFIX 0x0d
    +#define SIGP_STORE_STATUS_ADDR 0x0e
    +#define SIGP_SET_ARCH 0x12
    +
    +/* cpu status bits */
    +#define SIGP_STAT_EQUIPMENT_CHECK 0x80000000UL
    +#define SIGP_STAT_INCORRECT_STATE 0x00000200UL
    +#define SIGP_STAT_INVALID_PARAMETER 0x00000100UL
    +#define SIGP_STAT_EXT_CALL_PENDING 0x00000080UL
    +#define SIGP_STAT_STOPPED 0x00000040UL
    +#define SIGP_STAT_OPERATOR_INTERV 0x00000020UL
    +#define SIGP_STAT_CHECK_STOP 0x00000010UL
    +#define SIGP_STAT_INOPERATIVE 0x00000004UL
    +#define SIGP_STAT_INVALID_ORDER 0x00000002UL
    +#define SIGP_STAT_RECEIVER_CHECK 0x00000001UL
    +
    +
    +static int __sigp_sense(struct kvm_vcpu *vcpu, u16 cpu_addr, u64 *reg)
    +{
    + struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
    + int rc;
    +
    + if (cpu_addr >= KVM_MAX_VCPUS)
    + return 3; /* not operational */
    +
    + spin_lock_bh(&fi->lock);
    + if (fi->local_int[cpu_addr] == NULL)
    + rc = 3; /* not operational */
    + else if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
    + & CPUSTAT_RUNNING) {
    + *reg &= 0xffffffff00000000UL;
    + rc = 1; /* status stored */
    + } else {
    + *reg &= 0xffffffff00000000UL;
    + *reg |= SIGP_STAT_STOPPED;
    + rc = 1; /* status stored */
    + }
    + spin_unlock_bh(&fi->lock);
    +
    + VCPU_EVENT(vcpu, 4, "sensed status of cpu %x rc %x", cpu_addr, rc);
    + return rc;
    +}
    +
    +static int __sigp_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr)
    +{
    + struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
    + struct local_interrupt *li;
    + struct interrupt_info *inti;
    + int rc;
    +
    + if (cpu_addr >= KVM_MAX_VCPUS)
    + return 3; /* not operational */
    +
    + inti = kzalloc(sizeof(*inti), GFP_KERNEL);
    + if (!inti)
    + return -ENOMEM;
    +
    + inti->type = KVM_S390_INT_EMERGENCY;
    +
    + spin_lock_bh(&fi->lock);
    + li = fi->local_int[cpu_addr];
    + if (li == NULL) {
    + rc = 3; /* not operational */
    + kfree(inti);
    + goto unlock;
    + }
    + spin_lock_bh(&li->lock);
    + list_add_tail(&inti->list, &li->list);
    + atomic_set(&li->active, 1);
    + atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
    + if (waitqueue_active(&li->wq))
    + wake_up_interruptible(&li->wq);
    + spin_unlock_bh(&li->lock);
    + rc = 0; /* order accepted */
    +unlock:
    + spin_unlock_bh(&fi->lock);
    + VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
    + return rc;
    +}
    +
    +static int __sigp_stop(struct kvm_vcpu *vcpu, u16 cpu_addr, int store)
    +{
    + struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
    + struct local_interrupt *li;
    + struct interrupt_info *inti;
    + int rc;
    +
    + if (cpu_addr >= KVM_MAX_VCPUS)
    + return 3; /* not operational */
    +
    + inti = kzalloc(sizeof(*inti), GFP_KERNEL);
    + if (!inti)
    + return -ENOMEM;
    +
    + inti->type = KVM_S390_SIGP_STOP;
    +
    + spin_lock_bh(&fi->lock);
    + li = fi->local_int[cpu_addr];
    + if (li == NULL) {
    + rc = 3; /* not operational */
    + kfree(inti);
    + goto unlock;
    + }
    + spin_lock_bh(&li->lock);
    + list_add_tail(&inti->list, &li->list);
    + atomic_set(&li->active, 1);
    + atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
    + if (store)
    + li->action_bits |= ACTION_STORE_ON_STOP;
    + li->action_bits |= ACTION_STOP_ON_STOP;
    + if (waitqueue_active(&li->wq))
    + wake_up_interruptible(&li->wq);
    + spin_unlock_bh(&li->lock);
    + rc = 0; /* order accepted */
    +unlock:
    + spin_unlock_bh(&fi->lock);
    + VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x", cpu_addr);
    + return rc;
    +}
    +
    +static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
    +{
    + int rc;
    +
    + switch (parameter & 0xff) {
    + case 0:
    + printk(KERN_WARNING "kvm: request to switch to ESA/390 mode"
    + " not supported");
    + rc = 3; /* not operational */
    + break;
    + case 1:
    + case 2:
    + rc = 0; /* order accepted */
    + break;
    + default:
    + rc = -ENOTSUPP;
    + }
    + return rc;
    +}
    +
    +static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
    + u64 *reg)
    +{
    + struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
    + struct local_interrupt *li;
    + struct interrupt_info *inti;
    + int rc;
    + u8 tmp;
    +
    + /* make sure that the new value is valid memory */
    + address = address & 0x7fffe000u;
    + if ((copy_from_guest(vcpu, &tmp,
    + (u64) (address + vcpu->kvm->arch.guest_origin) , 1)) ||
    + (copy_from_guest(vcpu, &tmp, (u64) (address +
    + vcpu->kvm->arch.guest_origin + PAGE_SIZE), 1))) {
    + *reg |= SIGP_STAT_INVALID_PARAMETER;
    + return 1; /* invalid parameter */
    + }
    +
    + inti = kzalloc(sizeof(*inti), GFP_KERNEL);
    + if (!inti)
    + return 2; /* busy */
    +
    + spin_lock_bh(&fi->lock);
    + li = fi->local_int[cpu_addr];
    +
    + if ((cpu_addr >= KVM_MAX_VCPUS) || (li == NULL)) {
    + rc = 1; /* incorrect state */
    + *reg &= SIGP_STAT_INCORRECT_STATE;
    + kfree(inti);
    + goto out_fi;
    + }
    +
    + spin_lock_bh(&li->lock);
    + /* cpu must be in stopped state */
    + if (atomic_read(li->cpuflags) & CPUSTAT_RUNNING) {
    + rc = 1; /* incorrect state */
    + *reg &= SIGP_STAT_INCORRECT_STATE;
    + kfree(inti);
    + goto out_li;
    + }
    +
    + inti->type = KVM_S390_SIGP_SET_PREFIX;
    + inti->prefix.address = address;
    +
    + list_add_tail(&inti->list, &li->list);
    + atomic_set(&li->active, 1);
    + if (waitqueue_active(&li->wq))
    + wake_up_interruptible(&li->wq);
    + rc = 0; /* order accepted */
    +
    + VCPU_EVENT(vcpu, 4, "set prefix of cpu %02x to %x", cpu_addr, address);
    +out_li:
    + spin_unlock_bh(&li->lock);
    +out_fi:
    + spin_unlock_bh(&fi->lock);
    + return rc;
    +}
    +
    +int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
    +{
    + int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
    + int r3 = vcpu->arch.sie_block->ipa & 0x000f;
    + int base2 = vcpu->arch.sie_block->ipb >> 28;
    + int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
    + u32 parameter;
    + u16 cpu_addr = vcpu->arch.guest_gprs[r3];
    + u8 order_code;
    + int rc;
    +
    + order_code = disp2;
    + if (base2)
    + order_code += vcpu->arch.guest_gprs[base2];
    +
    + if (r1 % 2)
    + parameter = vcpu->arch.guest_gprs[r1];
    + else
    + parameter = vcpu->arch.guest_gprs[r1 + 1];
    +
    + switch (order_code) {
    + case SIGP_SENSE:
    + vcpu->stat.instruction_sigp_sense++;
    + rc = __sigp_sense(vcpu, cpu_addr,
    + &vcpu->arch.guest_gprs[r1]);
    + break;
    + case SIGP_EMERGENCY:
    + vcpu->stat.instruction_sigp_emergency++;
    + rc = __sigp_emergency(vcpu, cpu_addr);
    + break;
    + case SIGP_STOP:
    + vcpu->stat.instruction_sigp_stop++;
    + rc = __sigp_stop(vcpu, cpu_addr, 0);
    + break;
    + case SIGP_STOP_STORE_STATUS:
    + vcpu->stat.instruction_sigp_stop++;
    + rc = __sigp_stop(vcpu, cpu_addr, 1);
    + break;
    + case SIGP_SET_ARCH:
    + vcpu->stat.instruction_sigp_arch++;
    + rc = __sigp_set_arch(vcpu, parameter);
    + break;
    + case SIGP_SET_PREFIX:
    + vcpu->stat.instruction_sigp_prefix++;
    + rc = __sigp_set_prefix(vcpu, cpu_addr, parameter,
    + &vcpu->arch.guest_gprs[r1]);
    + break;
    + case SIGP_RESTART:
    + vcpu->stat.instruction_sigp_restart++;
    + /* user space must know about restart */
    + default:
    + return -ENOTSUPP;
    + }
    +
    + if (rc < 0)
    + return rc;
    +
    + vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
    + vcpu->arch.sie_block->gpsw.mask |= (rc & 3ul) << 44;
    + return 0;
    +}
    diff --git a/include/asm-s390/kvm_host.h b/include/asm-s390/kvm_host.h
    index 2eaf6fe..1c829bd 100644
    --- a/include/asm-s390/kvm_host.h
    +++ b/include/asm-s390/kvm_host.h
    @@ -128,6 +128,12 @@ struct kvm_vcpu_stat {
    u32 instruction_chsc;
    u32 instruction_stsi;
    u32 instruction_stfl;
    + u32 instruction_sigp_sense;
    + u32 instruction_sigp_emergency;
    + u32 instruction_sigp_stop;
    + u32 instruction_sigp_arch;
    + u32 instruction_sigp_prefix;
    + u32 instruction_sigp_restart;
    };

    struct io_info {
    @@ -169,6 +175,10 @@ struct interrupt_info {
    };
    };

    +/* for local_interrupt.action_flags */
    +#define ACTION_STORE_ON_STOP 1
    +#define ACTION_STOP_ON_STOP 2
    +
    struct local_interrupt {
    spinlock_t lock;
    struct list_head list;
    @@ -176,6 +186,8 @@ struct local_interrupt {
    struct float_interrupt *float_int;
    int timer_due; /* event indicator for waitqueue below */
    wait_queue_head_t wq;
    + atomic_t *cpuflags;
    + unsigned int action_bits;
    };

    struct float_interrupt {
    --
    1.5.5


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