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linux/arch/s390/kvm/intercept.c
Christian Borntraeger a5efb6b6c9 KVM: s390: reject invalid modes for runtime instrumentation 
Usually a validity intercept is a programming error of the host
because of invalid entries in the state description.
We can get a validity intercept if the mode of the runtime
instrumentation control block is wrong. As the host does not know
which modes are valid, this can be used by userspace to trigger
a WARN.
Instead of printing a WARN let's return an error to userspace as
this can only happen if userspace provides a malformed initial
value (e.g. on migration). The kernel should never warn on bogus
input. Instead let's log it into the s390 debug feature.

While at it, let's return -EINVAL for all validity intercepts as
this will trigger an error in QEMU like

error: kvm run failed Invalid argument
PSW=mask 0404c00180000000 addr 000000000063c226 cc 00
R00=000000000000004f R01=0000000000000004 R02=0000000000760005 R03=000000007fe0a000
R04=000000000064ba2a R05=000000049db73dd0 R06=000000000082c4b0 R07=0000000000000041
R08=0000000000000002 R09=000003e0804042a8 R10=0000000496152c42 R11=000000007fe0afb0
[...]

This will avoid an endless loop of validity intercepts.

Cc: stable@vger.kernel.org # v4.5+
Fixes: c6e5f16637 ("KVM: s390: implement the RI support of guest")
Acked-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2016-10-20 20:06:12 +02:00

416 lines
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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,
[0xaa] = kvm_s390_handle_aa,
[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,
};
u8 kvm_s390_get_ilen(struct kvm_vcpu *vcpu)
{
struct kvm_s390_sie_block *sie_block = vcpu->arch.sie_block;
u8 ilen = 0;
switch (vcpu->arch.sie_block->icptcode) {
case ICPT_INST:
case ICPT_INSTPROGI:
case ICPT_OPEREXC:
case ICPT_PARTEXEC:
case ICPT_IOINST:
/* instruction only stored for these icptcodes */
ilen = insn_length(vcpu->arch.sie_block->ipa >> 8);
/* Use the length of the EXECUTE instruction if necessary */
if (sie_block->icptstatus & 1) {
ilen = (sie_block->icptstatus >> 4) & 0x6;
if (!ilen)
ilen = 4;
}
break;
case ICPT_PROGI:
/* bit 1+2 of pgmilc are the ilc, so we directly get ilen */
ilen = vcpu->arch.sie_block->pgmilc & 0x6;
break;
}
return ilen;
}
static int handle_noop(struct kvm_vcpu *vcpu)
{
switch (vcpu->arch.sie_block->icptcode) {
case 0x10:
vcpu->stat.exit_external_request++;
break;
default:
break; /* nothing */
}
return 0;
}
static int handle_stop(struct kvm_vcpu *vcpu)
{
struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
int rc = 0;
uint8_t flags, stop_pending;
vcpu->stat.exit_stop_request++;
/* delay the stop if any non-stop irq is pending */
if (kvm_s390_vcpu_has_irq(vcpu, 1))
return 0;
/* avoid races with the injection/SIGP STOP code */
spin_lock(&li->lock);
flags = li->irq.stop.flags;
stop_pending = kvm_s390_is_stop_irq_pending(vcpu);
spin_unlock(&li->lock);
trace_kvm_s390_stop_request(stop_pending, flags);
if (!stop_pending)
return 0;
if (flags & KVM_S390_STOP_FLAG_STORE_STATUS) {
rc = kvm_s390_vcpu_store_status(vcpu,
KVM_S390_STORE_STATUS_NOADDR);
if (rc)
return rc;
}
if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
kvm_s390_vcpu_stop(vcpu);
return -EOPNOTSUPP;
}
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);
KVM_EVENT(3, "validity intercept 0x%x for pid %u (kvm 0x%pK)", viwhy,
current->pid, vcpu->kvm);
/* do not warn on invalid runtime instrumentation mode */
WARN_ONCE(viwhy != 0x44, "kvm: unhandled validity intercept 0x%x\n",
viwhy);
return -EINVAL;
}
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 int inject_prog_on_prog_intercept(struct kvm_vcpu *vcpu)
{
struct kvm_s390_pgm_info pgm_info = {
.code = vcpu->arch.sie_block->iprcc,
/* the PSW has already been rewound */
.flags = KVM_S390_PGM_FLAGS_NO_REWIND,
};
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_VECTOR_PROCESSING:
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;
}
return kvm_s390_inject_prog_irq(vcpu, &pgm_info);
}
/*
* 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)
{
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;
return inject_prog_on_prog_intercept(vcpu);
}
/**
* 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_irq 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.u.extcall.code = vcpu->arch.sie_block->extcpuaddr;
rc = kvm_s390_inject_vcpu(vcpu, &irq);
/* ignore if another external call is already pending */
if (rc == -EBUSY)
return 0;
return rc;
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 srcaddr, dstaddr;
int reg1, reg2, rc;
kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
/* Make sure that the source is paged-in */
rc = guest_translate_address(vcpu, vcpu->run->s.regs.gprs[reg2],
reg2, &srcaddr, GACC_FETCH);
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);
rc = kvm_arch_fault_in_page(vcpu, srcaddr, 0);
if (rc != 0)
return rc;
/* Make sure that the destination is paged-in */
rc = guest_translate_address(vcpu, vcpu->run->s.regs.gprs[reg1],
reg1, &dstaddr, GACC_STORE);
if (rc)
return kvm_s390_inject_prog_cond(vcpu, rc);
rc = kvm_arch_fault_in_page(vcpu, dstaddr, 1);
if (rc != 0)
return rc;
kvm_s390_retry_instr(vcpu);
return 0;
}
static int handle_partial_execution(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_pei++;
if (vcpu->arch.sie_block->ipa == 0xb254) /* MVPG */
return handle_mvpg_pei(vcpu);
if (vcpu->arch.sie_block->ipa >> 8 == 0xae) /* SIGP */
return kvm_s390_handle_sigp_pei(vcpu);
return -EOPNOTSUPP;
}
static int handle_operexc(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_operation_exception++;
trace_kvm_s390_handle_operexc(vcpu, vcpu->arch.sie_block->ipa,
vcpu->arch.sie_block->ipb);
if (vcpu->arch.sie_block->ipa == 0xb256 &&
test_kvm_facility(vcpu->kvm, 74))
return handle_sthyi(vcpu);
if (vcpu->arch.sie_block->ipa == 0 && vcpu->kvm->arch.user_instr0)
return -EOPNOTSUPP;
return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
}
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
{
int rc, per_rc = 0;
if (kvm_is_ucontrol(vcpu->kvm))
return -EOPNOTSUPP;
switch (vcpu->arch.sie_block->icptcode) {
case 0x10:
case 0x18:
return handle_noop(vcpu);
case 0x04:
rc = handle_instruction(vcpu);
break;
case 0x08:
return handle_prog(vcpu);
case 0x14:
return handle_external_interrupt(vcpu);
case 0x1c:
return kvm_s390_handle_wait(vcpu);
case 0x20:
return handle_validity(vcpu);
case 0x28:
return handle_stop(vcpu);
case 0x2c:
rc = handle_operexc(vcpu);
break;
case 0x38:
rc = handle_partial_execution(vcpu);
break;
default:
return -EOPNOTSUPP;
}
/* process PER, also if the instrution is processed in user space */
if (vcpu->arch.sie_block->icptstatus & 0x02 &&
(!rc || rc == -EOPNOTSUPP))
per_rc = kvm_s390_handle_per_ifetch_icpt(vcpu);
return per_rc ? per_rc : rc;
}
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