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linux/arch/s390/kvm/sigp.c
Eric Farman 8eeba194a3 KVM: s390: Simplify SIGP Set Arch handling 
The Principles of Operations describe the various reasons that
each individual SIGP orders might be rejected, and the status
bit that are set for each condition.

For example, for the Set Architecture order, it states:

  "If it is not true that all other CPUs in the configu-
   ration are in the stopped or check-stop state, ...
   bit 54 (incorrect state) ... is set to one."

However, it also states:

  "... if the CZAM facility is installed, ...
   bit 55 (invalid parameter) ... is set to one."

Since the Configuration-z/Architecture-Architectural Mode (CZAM)
facility is unconditionally presented, there is no need to examine
each VCPU to determine if it is started/stopped. It can simply be
rejected outright with the Invalid Parameter bit.

Fixes: b697e435ae ("KVM: s390: Support Configuration z/Architecture Mode")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20211008203112.1979843-2-farman@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2021-10-25 09:20:39 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* handling interprocessor communication
*
* Copyright IBM Corp. 2008, 2013
*
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Christian Borntraeger <borntraeger@de.ibm.com>
* Christian Ehrhardt <ehrhardt@de.ibm.com>
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/slab.h>
#include <asm/sigp.h>
#include "gaccess.h"
#include "kvm-s390.h"
#include "trace.h"
static int __sigp_sense(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
u64 *reg)
{
const bool stopped = kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_STOPPED);
int rc;
int ext_call_pending;
ext_call_pending = kvm_s390_ext_call_pending(dst_vcpu);
if (!stopped && !ext_call_pending)
rc = SIGP_CC_ORDER_CODE_ACCEPTED;
else {
*reg &= 0xffffffff00000000UL;
if (ext_call_pending)
*reg |= SIGP_STATUS_EXT_CALL_PENDING;
if (stopped)
*reg |= SIGP_STATUS_STOPPED;
rc = SIGP_CC_STATUS_STORED;
}
VCPU_EVENT(vcpu, 4, "sensed status of cpu %x rc %x", dst_vcpu->vcpu_id,
rc);
return rc;
}
static int __inject_sigp_emergency(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu)
{
struct kvm_s390_irq irq = {
.type = KVM_S390_INT_EMERGENCY,
.u.emerg.code = vcpu->vcpu_id,
};
int rc = 0;
rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
if (!rc)
VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x",
dst_vcpu->vcpu_id);
return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
}
static int __sigp_emergency(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu)
{
return __inject_sigp_emergency(vcpu, dst_vcpu);
}
static int __sigp_conditional_emergency(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu,
u16 asn, u64 *reg)
{
const u64 psw_int_mask = PSW_MASK_IO | PSW_MASK_EXT;
u16 p_asn, s_asn;
psw_t *psw;
bool idle;
idle = is_vcpu_idle(vcpu);
psw = &dst_vcpu->arch.sie_block->gpsw;
p_asn = dst_vcpu->arch.sie_block->gcr[4] & 0xffff; /* Primary ASN */
s_asn = dst_vcpu->arch.sie_block->gcr[3] & 0xffff; /* Secondary ASN */
/* Inject the emergency signal? */
if (!is_vcpu_stopped(vcpu)
|| (psw->mask & psw_int_mask) != psw_int_mask
|| (idle && psw->addr != 0)
|| (!idle && (asn == p_asn || asn == s_asn))) {
return __inject_sigp_emergency(vcpu, dst_vcpu);
} else {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
return SIGP_CC_STATUS_STORED;
}
}
static int __sigp_external_call(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu, u64 *reg)
{
struct kvm_s390_irq irq = {
.type = KVM_S390_INT_EXTERNAL_CALL,
.u.extcall.code = vcpu->vcpu_id,
};
int rc;
rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
if (rc == -EBUSY) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_EXT_CALL_PENDING;
return SIGP_CC_STATUS_STORED;
} else if (rc == 0) {
VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x",
dst_vcpu->vcpu_id);
}
return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
}
static int __sigp_stop(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu)
{
struct kvm_s390_irq irq = {
.type = KVM_S390_SIGP_STOP,
};
int rc;
rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
if (rc == -EBUSY)
rc = SIGP_CC_BUSY;
else if (rc == 0)
VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x",
dst_vcpu->vcpu_id);
return rc;
}
static int __sigp_stop_and_store_status(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu, u64 *reg)
{
struct kvm_s390_irq irq = {
.type = KVM_S390_SIGP_STOP,
.u.stop.flags = KVM_S390_STOP_FLAG_STORE_STATUS,
};
int rc;
rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
if (rc == -EBUSY)
rc = SIGP_CC_BUSY;
else if (rc == 0)
VCPU_EVENT(vcpu, 4, "sent sigp stop and store status to cpu %x",
dst_vcpu->vcpu_id);
return rc;
}
static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter,
u64 *status_reg)
{
*status_reg &= 0xffffffff00000000UL;
/* Reject set arch order, with czam we're always in z/Arch mode. */
*status_reg |= SIGP_STATUS_INVALID_PARAMETER;
return SIGP_CC_STATUS_STORED;
}
static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
u32 address, u64 *reg)
{
struct kvm_s390_irq irq = {
.type = KVM_S390_SIGP_SET_PREFIX,
.u.prefix.address = address & 0x7fffe000u,
};
int rc;
/*
* Make sure the new value is valid memory. We only need to check the
* first page, since address is 8k aligned and memory pieces are always
* at least 1MB aligned and have at least a size of 1MB.
*/
if (kvm_is_error_gpa(vcpu->kvm, irq.u.prefix.address)) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INVALID_PARAMETER;
return SIGP_CC_STATUS_STORED;
}
rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
if (rc == -EBUSY) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
return SIGP_CC_STATUS_STORED;
}
return rc;
}
static int __sigp_store_status_at_addr(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu,
u32 addr, u64 *reg)
{
int rc;
if (!kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_STOPPED)) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
return SIGP_CC_STATUS_STORED;
}
addr &= 0x7ffffe00;
rc = kvm_s390_store_status_unloaded(dst_vcpu, addr);
if (rc == -EFAULT) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INVALID_PARAMETER;
rc = SIGP_CC_STATUS_STORED;
}
return rc;
}
static int __sigp_sense_running(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu, u64 *reg)
{
int rc;
if (!test_kvm_facility(vcpu->kvm, 9)) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INVALID_ORDER;
return SIGP_CC_STATUS_STORED;
}
if (kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_RUNNING)) {
/* running */
rc = SIGP_CC_ORDER_CODE_ACCEPTED;
} else {
/* not running */
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_NOT_RUNNING;
rc = SIGP_CC_STATUS_STORED;
}
VCPU_EVENT(vcpu, 4, "sensed running status of cpu %x rc %x",
dst_vcpu->vcpu_id, rc);
return rc;
}
static int __prepare_sigp_re_start(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu, u8 order_code)
{
struct kvm_s390_local_interrupt *li = &dst_vcpu->arch.local_int;
/* handle (RE)START in user space */
int rc = -EOPNOTSUPP;
/* make sure we don't race with STOP irq injection */
spin_lock(&li->lock);
if (kvm_s390_is_stop_irq_pending(dst_vcpu))
rc = SIGP_CC_BUSY;
spin_unlock(&li->lock);
return rc;
}
static int __prepare_sigp_cpu_reset(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu, u8 order_code)
{
/* handle (INITIAL) CPU RESET in user space */
return -EOPNOTSUPP;
}
static int __prepare_sigp_unknown(struct kvm_vcpu *vcpu,
struct kvm_vcpu *dst_vcpu)
{
/* handle unknown orders in user space */
return -EOPNOTSUPP;
}
static int handle_sigp_dst(struct kvm_vcpu *vcpu, u8 order_code,
u16 cpu_addr, u32 parameter, u64 *status_reg)
{
int rc;
struct kvm_vcpu *dst_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
switch (order_code) {
case SIGP_SENSE:
vcpu->stat.instruction_sigp_sense++;
rc = __sigp_sense(vcpu, dst_vcpu, status_reg);
break;
case SIGP_EXTERNAL_CALL:
vcpu->stat.instruction_sigp_external_call++;
rc = __sigp_external_call(vcpu, dst_vcpu, status_reg);
break;
case SIGP_EMERGENCY_SIGNAL:
vcpu->stat.instruction_sigp_emergency++;
rc = __sigp_emergency(vcpu, dst_vcpu);
break;
case SIGP_STOP:
vcpu->stat.instruction_sigp_stop++;
rc = __sigp_stop(vcpu, dst_vcpu);
break;
case SIGP_STOP_AND_STORE_STATUS:
vcpu->stat.instruction_sigp_stop_store_status++;
rc = __sigp_stop_and_store_status(vcpu, dst_vcpu, status_reg);
break;
case SIGP_STORE_STATUS_AT_ADDRESS:
vcpu->stat.instruction_sigp_store_status++;
rc = __sigp_store_status_at_addr(vcpu, dst_vcpu, parameter,
status_reg);
break;
case SIGP_SET_PREFIX:
vcpu->stat.instruction_sigp_prefix++;
rc = __sigp_set_prefix(vcpu, dst_vcpu, parameter, status_reg);
break;
case SIGP_COND_EMERGENCY_SIGNAL:
vcpu->stat.instruction_sigp_cond_emergency++;
rc = __sigp_conditional_emergency(vcpu, dst_vcpu, parameter,
status_reg);
break;
case SIGP_SENSE_RUNNING:
vcpu->stat.instruction_sigp_sense_running++;
rc = __sigp_sense_running(vcpu, dst_vcpu, status_reg);
break;
case SIGP_START:
vcpu->stat.instruction_sigp_start++;
rc = __prepare_sigp_re_start(vcpu, dst_vcpu, order_code);
break;
case SIGP_RESTART:
vcpu->stat.instruction_sigp_restart++;
rc = __prepare_sigp_re_start(vcpu, dst_vcpu, order_code);
break;
case SIGP_INITIAL_CPU_RESET:
vcpu->stat.instruction_sigp_init_cpu_reset++;
rc = __prepare_sigp_cpu_reset(vcpu, dst_vcpu, order_code);
break;
case SIGP_CPU_RESET:
vcpu->stat.instruction_sigp_cpu_reset++;
rc = __prepare_sigp_cpu_reset(vcpu, dst_vcpu, order_code);
break;
default:
vcpu->stat.instruction_sigp_unknown++;
rc = __prepare_sigp_unknown(vcpu, dst_vcpu);
}
if (rc == -EOPNOTSUPP)
VCPU_EVENT(vcpu, 4,
"sigp order %u -> cpu %x: handled in user space",
order_code, dst_vcpu->vcpu_id);
return rc;
}
static int handle_sigp_order_in_user_space(struct kvm_vcpu *vcpu, u8 order_code,
u16 cpu_addr)
{
if (!vcpu->kvm->arch.user_sigp)
return 0;
switch (order_code) {
case SIGP_SENSE:
case SIGP_EXTERNAL_CALL:
case SIGP_EMERGENCY_SIGNAL:
case SIGP_COND_EMERGENCY_SIGNAL:
case SIGP_SENSE_RUNNING:
return 0;
/* update counters as we're directly dropping to user space */
case SIGP_STOP:
vcpu->stat.instruction_sigp_stop++;
break;
case SIGP_STOP_AND_STORE_STATUS:
vcpu->stat.instruction_sigp_stop_store_status++;
break;
case SIGP_STORE_STATUS_AT_ADDRESS:
vcpu->stat.instruction_sigp_store_status++;
break;
case SIGP_STORE_ADDITIONAL_STATUS:
vcpu->stat.instruction_sigp_store_adtl_status++;
break;
case SIGP_SET_PREFIX:
vcpu->stat.instruction_sigp_prefix++;
break;
case SIGP_START:
vcpu->stat.instruction_sigp_start++;
break;
case SIGP_RESTART:
vcpu->stat.instruction_sigp_restart++;
break;
case SIGP_INITIAL_CPU_RESET:
vcpu->stat.instruction_sigp_init_cpu_reset++;
break;
case SIGP_CPU_RESET:
vcpu->stat.instruction_sigp_cpu_reset++;
break;
default:
vcpu->stat.instruction_sigp_unknown++;
}
VCPU_EVENT(vcpu, 3, "SIGP: order %u for CPU %d handled in userspace",
order_code, cpu_addr);
return 1;
}
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;
u32 parameter;
u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
u8 order_code;
int rc;
/* sigp in userspace can exit */
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
order_code = kvm_s390_get_base_disp_rs(vcpu, NULL);
if (handle_sigp_order_in_user_space(vcpu, order_code, cpu_addr))
return -EOPNOTSUPP;
if (r1 % 2)
parameter = vcpu->run->s.regs.gprs[r1];
else
parameter = vcpu->run->s.regs.gprs[r1 + 1];
trace_kvm_s390_handle_sigp(vcpu, order_code, cpu_addr, parameter);
switch (order_code) {
case SIGP_SET_ARCHITECTURE:
vcpu->stat.instruction_sigp_arch++;
rc = __sigp_set_arch(vcpu, parameter,
&vcpu->run->s.regs.gprs[r1]);
break;
default:
rc = handle_sigp_dst(vcpu, order_code, cpu_addr,
parameter,
&vcpu->run->s.regs.gprs[r1]);
}
if (rc < 0)
return rc;
kvm_s390_set_psw_cc(vcpu, rc);
return 0;
}
/*
* Handle SIGP partial execution interception.
*
* This interception will occur at the source cpu when a source cpu sends an
* external call to a target cpu and the target cpu has the WAIT bit set in
* its cpuflags. Interception will occurr after the interrupt indicator bits at
* the target cpu have been set. All error cases will lead to instruction
* interception, therefore nothing is to be checked or prepared.
*/
int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu)
{
int r3 = vcpu->arch.sie_block->ipa & 0x000f;
u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
struct kvm_vcpu *dest_vcpu;
u8 order_code = kvm_s390_get_base_disp_rs(vcpu, NULL);
trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr);
if (order_code == SIGP_EXTERNAL_CALL) {
dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
BUG_ON(dest_vcpu == NULL);
kvm_s390_vcpu_wakeup(dest_vcpu);
kvm_s390_set_psw_cc(vcpu, SIGP_CC_ORDER_CODE_ACCEPTED);
return 0;
}
return -EOPNOTSUPP;
}
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