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Commit 5288fbf0 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Avi Kivity
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KVM: s390: interprocessor communication via sigp 



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: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 453423dc

arch/s390/kvm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/s390/kvm/intercept.c

+20 −2
Original line number Diff line number Diff line
@@ -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)

arch/s390/kvm/kvm-s390.c

+7 −0
Original line number Diff line number Diff line
@@ -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);

arch/s390/kvm/kvm-s390.h

+7 −0
Original line number Diff line number Diff line
@@ -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

arch/s390/kvm/sigp.c

0 → 100644
+288 −0
Original line number Diff line number Diff line 
/*

 * 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;

}