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684135e096
linux/arch/s390/kvm/intercept.c
Thomas Huth 684135e096 KVM: s390: Avoid endless loops of specification exceptions 
If the new PSW for program interrupts is invalid, the VM ends up
in an endless loop of specification exceptions. Since there is not
much left we can do in this case, we should better drop to userspace
instead so that the crash can be reported to the user.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-05-16 14:57:19 +02:00

363 lines
9.6 KiB
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/*
* in-kernel handling for sie intercepts
*
* Copyright IBM Corp. 2008, 2014
*
* 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_host.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <asm/kvm_host.h>
#include <asm/asm-offsets.h>
#include <asm/irq.h>
#include "kvm-s390.h"
#include "gaccess.h"
#include "trace.h"
#include "trace-s390.h"
static const intercept_handler_t instruction_handlers[256] = {
[0x01] = kvm_s390_handle_01,
[0x82] = kvm_s390_handle_lpsw,
[0x83] = kvm_s390_handle_diag,
[0xae] = kvm_s390_handle_sigp,
[0xb2] = kvm_s390_handle_b2,
[0xb6] = kvm_s390_handle_stctl,
[0xb7] = kvm_s390_handle_lctl,
[0xb9] = kvm_s390_handle_b9,
[0xe5] = kvm_s390_handle_e5,
[0xeb] = kvm_s390_handle_eb,
};
static int handle_noop(struct kvm_vcpu *vcpu)
{
switch (vcpu->arch.sie_block->icptcode) {
case 0x0:
vcpu->stat.exit_null++;
break;
case 0x10:
vcpu->stat.exit_external_request++;
break;
default:
break; /* nothing */
}
return 0;
}
static int handle_stop(struct kvm_vcpu *vcpu)
{
int rc = 0;
vcpu->stat.exit_stop_request++;
spin_lock_bh(&vcpu->arch.local_int.lock);
trace_kvm_s390_stop_request(vcpu->arch.local_int.action_bits);
if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
kvm_s390_vcpu_stop(vcpu);
vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
rc = -EOPNOTSUPP;
}
if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
/* store status must be called unlocked. Since local_int.lock
* only protects local_int.* and not guest memory we can give
* up the lock here */
spin_unlock_bh(&vcpu->arch.local_int.lock);
rc = kvm_s390_vcpu_store_status(vcpu,
KVM_S390_STORE_STATUS_NOADDR);
if (rc >= 0)
rc = -EOPNOTSUPP;
} else
spin_unlock_bh(&vcpu->arch.local_int.lock);
return rc;
}
static int handle_validity(struct kvm_vcpu *vcpu)
{
int viwhy = vcpu->arch.sie_block->ipb >> 16;
vcpu->stat.exit_validity++;
trace_kvm_s390_intercept_validity(vcpu, viwhy);
WARN_ONCE(true, "kvm: unhandled validity intercept 0x%x\n", viwhy);
return -EOPNOTSUPP;
}
static int handle_instruction(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
vcpu->stat.exit_instruction++;
trace_kvm_s390_intercept_instruction(vcpu,
vcpu->arch.sie_block->ipa,
vcpu->arch.sie_block->ipb);
handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
if (handler)
return handler(vcpu);
return -EOPNOTSUPP;
}
static void __extract_prog_irq(struct kvm_vcpu *vcpu,
struct kvm_s390_pgm_info *pgm_info)
{
memset(pgm_info, 0, sizeof(struct kvm_s390_pgm_info));
pgm_info->code = vcpu->arch.sie_block->iprcc;
switch (vcpu->arch.sie_block->iprcc & ~PGM_PER) {
case PGM_AFX_TRANSLATION:
case PGM_ASX_TRANSLATION:
case PGM_EX_TRANSLATION:
case PGM_LFX_TRANSLATION:
case PGM_LSTE_SEQUENCE:
case PGM_LSX_TRANSLATION:
case PGM_LX_TRANSLATION:
case PGM_PRIMARY_AUTHORITY:
case PGM_SECONDARY_AUTHORITY:
case PGM_SPACE_SWITCH:
pgm_info->trans_exc_code = vcpu->arch.sie_block->tecmc;
break;
case PGM_ALEN_TRANSLATION:
case PGM_ALE_SEQUENCE:
case PGM_ASTE_INSTANCE:
case PGM_ASTE_SEQUENCE:
case PGM_ASTE_VALIDITY:
case PGM_EXTENDED_AUTHORITY:
pgm_info->exc_access_id = vcpu->arch.sie_block->eai;
break;
case PGM_ASCE_TYPE:
case PGM_PAGE_TRANSLATION:
case PGM_REGION_FIRST_TRANS:
case PGM_REGION_SECOND_TRANS:
case PGM_REGION_THIRD_TRANS:
case PGM_SEGMENT_TRANSLATION:
pgm_info->trans_exc_code = vcpu->arch.sie_block->tecmc;
pgm_info->exc_access_id = vcpu->arch.sie_block->eai;
pgm_info->op_access_id = vcpu->arch.sie_block->oai;
break;
case PGM_MONITOR:
pgm_info->mon_class_nr = vcpu->arch.sie_block->mcn;
pgm_info->mon_code = vcpu->arch.sie_block->tecmc;
break;
case PGM_DATA:
pgm_info->data_exc_code = vcpu->arch.sie_block->dxc;
break;
case PGM_PROTECTION:
pgm_info->trans_exc_code = vcpu->arch.sie_block->tecmc;
pgm_info->exc_access_id = vcpu->arch.sie_block->eai;
break;
default:
break;
}
if (vcpu->arch.sie_block->iprcc & PGM_PER) {
pgm_info->per_code = vcpu->arch.sie_block->perc;
pgm_info->per_atmid = vcpu->arch.sie_block->peratmid;
pgm_info->per_address = vcpu->arch.sie_block->peraddr;
pgm_info->per_access_id = vcpu->arch.sie_block->peraid;
}
}
/*
* restore ITDB to program-interruption TDB in guest lowcore
* and set TX abort indication if required
*/
static int handle_itdb(struct kvm_vcpu *vcpu)
{
struct kvm_s390_itdb *itdb;
int rc;
if (!IS_TE_ENABLED(vcpu) || !IS_ITDB_VALID(vcpu))
return 0;
if (current->thread.per_flags & PER_FLAG_NO_TE)
return 0;
itdb = (struct kvm_s390_itdb *)vcpu->arch.sie_block->itdba;
rc = write_guest_lc(vcpu, __LC_PGM_TDB, itdb, sizeof(*itdb));
if (rc)
return rc;
memset(itdb, 0, sizeof(*itdb));
return 0;
}
#define per_event(vcpu) (vcpu->arch.sie_block->iprcc & PGM_PER)
static int handle_prog(struct kvm_vcpu *vcpu)
{
struct kvm_s390_pgm_info pgm_info;
psw_t psw;
int rc;
vcpu->stat.exit_program_interruption++;
if (guestdbg_enabled(vcpu) && per_event(vcpu)) {
kvm_s390_handle_per_event(vcpu);
/* the interrupt might have been filtered out completely */
if (vcpu->arch.sie_block->iprcc == 0)
return 0;
}
trace_kvm_s390_intercept_prog(vcpu, vcpu->arch.sie_block->iprcc);
if (vcpu->arch.sie_block->iprcc == PGM_SPECIFICATION) {
rc = read_guest_lc(vcpu, __LC_PGM_NEW_PSW, &psw, sizeof(psw_t));
if (rc)
return rc;
/* Avoid endless loops of specification exceptions */
if (!is_valid_psw(&psw))
return -EOPNOTSUPP;
}
rc = handle_itdb(vcpu);
if (rc)
return rc;
__extract_prog_irq(vcpu, &pgm_info);
return kvm_s390_inject_prog_irq(vcpu, &pgm_info);
}
static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
{
int rc, rc2;
vcpu->stat.exit_instr_and_program++;
rc = handle_instruction(vcpu);
rc2 = handle_prog(vcpu);
if (rc == -EOPNOTSUPP)
vcpu->arch.sie_block->icptcode = 0x04;
if (rc)
return rc;
return rc2;
}
/**
* handle_external_interrupt - used for external interruption interceptions
*
* This interception only occurs if the CPUSTAT_EXT_INT bit was set, or if
* the new PSW does not have external interrupts disabled. In the first case,
* we've got to deliver the interrupt manually, and in the second case, we
* drop to userspace to handle the situation there.
*/
static int handle_external_interrupt(struct kvm_vcpu *vcpu)
{
u16 eic = vcpu->arch.sie_block->eic;
struct kvm_s390_interrupt irq;
psw_t newpsw;
int rc;
vcpu->stat.exit_external_interrupt++;
rc = read_guest_lc(vcpu, __LC_EXT_NEW_PSW, &newpsw, sizeof(psw_t));
if (rc)
return rc;
/* We can not handle clock comparator or timer interrupt with bad PSW */
if ((eic == EXT_IRQ_CLK_COMP || eic == EXT_IRQ_CPU_TIMER) &&
(newpsw.mask & PSW_MASK_EXT))
return -EOPNOTSUPP;
switch (eic) {
case EXT_IRQ_CLK_COMP:
irq.type = KVM_S390_INT_CLOCK_COMP;
break;
case EXT_IRQ_CPU_TIMER:
irq.type = KVM_S390_INT_CPU_TIMER;
break;
case EXT_IRQ_EXTERNAL_CALL:
irq.type = KVM_S390_INT_EXTERNAL_CALL;
irq.parm = vcpu->arch.sie_block->extcpuaddr;
break;
default:
return -EOPNOTSUPP;
}
return kvm_s390_inject_vcpu(vcpu, &irq);
}
/**
* Handle MOVE PAGE partial execution interception.
*
* This interception can only happen for guests with DAT disabled and
* addresses that are currently not mapped in the host. Thus we try to
* set up the mappings for the corresponding user pages here (or throw
* addressing exceptions in case of illegal guest addresses).
*/
static int handle_mvpg_pei(struct kvm_vcpu *vcpu)
{
unsigned long hostaddr, srcaddr, dstaddr;
psw_t *psw = &vcpu->arch.sie_block->gpsw;
struct mm_struct *mm = current->mm;
int reg1, reg2, rc;
kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
srcaddr = kvm_s390_real_to_abs(vcpu, vcpu->run->s.regs.gprs[reg2]);
dstaddr = kvm_s390_real_to_abs(vcpu, vcpu->run->s.regs.gprs[reg1]);
/* Make sure that the source is paged-in */
hostaddr = gmap_fault(srcaddr, vcpu->arch.gmap);
if (IS_ERR_VALUE(hostaddr))
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
down_read(&mm->mmap_sem);
rc = get_user_pages(current, mm, hostaddr, 1, 0, 0, NULL, NULL);
up_read(&mm->mmap_sem);
if (rc < 0)
return rc;
/* Make sure that the destination is paged-in */
hostaddr = gmap_fault(dstaddr, vcpu->arch.gmap);
if (IS_ERR_VALUE(hostaddr))
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
down_read(&mm->mmap_sem);
rc = get_user_pages(current, mm, hostaddr, 1, 1, 0, NULL, NULL);
up_read(&mm->mmap_sem);
if (rc < 0)
return rc;
psw->addr = __rewind_psw(*psw, 4);
return 0;
}
static int handle_partial_execution(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.sie_block->ipa == 0xb254) /* MVPG */
return handle_mvpg_pei(vcpu);
return -EOPNOTSUPP;
}
static const intercept_handler_t intercept_funcs[] = {
[0x00 >> 2] = handle_noop,
[0x04 >> 2] = handle_instruction,
[0x08 >> 2] = handle_prog,
[0x0C >> 2] = handle_instruction_and_prog,
[0x10 >> 2] = handle_noop,
[0x14 >> 2] = handle_external_interrupt,
[0x18 >> 2] = handle_noop,
[0x1C >> 2] = kvm_s390_handle_wait,
[0x20 >> 2] = handle_validity,
[0x28 >> 2] = handle_stop,
[0x38 >> 2] = handle_partial_execution,
};
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
{
intercept_handler_t func;
u8 code = vcpu->arch.sie_block->icptcode;
if (code & 3 || (code >> 2) >= ARRAY_SIZE(intercept_funcs))
return -EOPNOTSUPP;
func = intercept_funcs[code >> 2];
if (func)
return func(vcpu);
return -EOPNOTSUPP;
}
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