Commit e28acfea authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Avi Kivity
Browse files

KVM: s390: intercepts for diagnose instructions 



This patch introduces interpretation of some diagnose instruction intercepts.
Diagnose is our classic architected way of doing a hypercall. This patch
features the following diagnose codes:
- vm storage size, that tells the guest about its memory layout
- time slice end, which is used by the guest to indicate that it waits
  for a lock and thus cannot use up its time slice in a useful way
- ipl functions, which a guest can use to reset and reboot itself

In order to implement ipl functions, we also introduce an exit reason that
causes userspace to perform various resets on the virtual machine. All resets
are described in the principles of operation book, except KVM_S390_RESET_IPL
which causes a reboot of the machine.

Acked-by: default avatarMartin Schwidefsky <martin.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 avatarAvi Kivity <avi@qumranet.com>
parent 5288fbf0

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 sigp.o

kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o sigp.o diag.o

obj-$(CONFIG_KVM) += kvm.o

arch/s390/kvm/diag.c

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/*

 * diag.c - handling diagnose instructions

 *

 * 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 "kvm-s390.h"



static int __diag_time_slice_end(struct kvm_vcpu *vcpu)

{

	VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");

	vcpu->stat.diagnose_44++;

	vcpu_put(vcpu);

	schedule();

	vcpu_load(vcpu);

	return 0;

}



static int __diag_ipl_functions(struct kvm_vcpu *vcpu)

{

	unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;

	unsigned long subcode = vcpu->arch.guest_gprs[reg] & 0xffff;



	VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);

	switch (subcode) {

	case 3:

		vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;

		break;

	case 4:

		vcpu->run->s390_reset_flags = 0;

		break;

	default:

		return -ENOTSUPP;

	}



	atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);

	vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;

	vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;

	vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;

	vcpu->run->exit_reason = KVM_EXIT_S390_RESET;

	VCPU_EVENT(vcpu, 3, "requesting userspace resets %lx",

	  vcpu->run->s390_reset_flags);

	return -EREMOTE;

}



int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)

{

	int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;



	switch (code) {

	case 0x44:

		return __diag_time_slice_end(vcpu);

	case 0x308:

		return __diag_ipl_functions(vcpu);

	default:

		return -ENOTSUPP;

	}

}

arch/s390/kvm/intercept.c

+1 −0
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] = {

	[0x83] = kvm_s390_handle_diag,

	[0xae] = kvm_s390_handle_sigp,

	[0xb2] = kvm_s390_handle_priv,

	[0xb7] = handle_lctl,

arch/s390/kvm/kvm-s390.c

+1 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "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) },

	{ "diagnose_44", VCPU_STAT(diagnose_44) },

	{ NULL }

};

arch/s390/kvm/kvm-s390.h

+3 −0
Original line number Diff line number Diff line
@@ -58,4 +58,7 @@ 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);

/* implemented in diag.c */

int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);



#endif

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