Commit 8f2abe6a authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Avi Kivity

KVM: s390: sie intercept handling

This path introduces handling of sie intercepts in three flavors: Intercepts
are either handled completely in-kernel by kvm_handle_sie_intercept(),
or passed to userspace with corresponding data in struct kvm_run in case
kvm_handle_sie_intercept() returns -ENOTSUPP.
In case of partial execution in kernel with the need of userspace support,
kvm_handle_sie_intercept() may choose to set up struct kvm_run and return
-EREMOTE.

The trivial intercept reasons are handled in this patch:
handle_noop() just does nothing for intercepts that don't require our support
  at all
handle_stop() is called when a cpu enters stopped state, and it drops out to
  userland after updating our vcpu state
handle_validity() faults in the cpu lowcore if needed, or passes the request
  to userland
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 avatarAvi Kivity <avi@qumranet.com>
parent b0c632db
......@@ -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
kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o
obj-$(CONFIG_KVM) += kvm.o
/*
* intercept.c - in-kernel handling for sie intercepts
*
* 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_host.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <asm/kvm_host.h>
#include "kvm-s390.h"
static int handle_noop(struct kvm_vcpu *vcpu)
{
switch (vcpu->arch.sie_block->icptcode) {
case 0x10:
vcpu->stat.exit_external_request++;
break;
case 0x14:
vcpu->stat.exit_external_interrupt++;
break;
default:
break; /* nothing */
}
return 0;
}
static int handle_stop(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_stop_request++;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
return -ENOTSUPP;
}
static int handle_validity(struct kvm_vcpu *vcpu)
{
int viwhy = vcpu->arch.sie_block->ipb >> 16;
vcpu->stat.exit_validity++;
if (viwhy == 0x37) {
fault_in_pages_writeable((char __user *)
vcpu->kvm->arch.guest_origin +
vcpu->arch.sie_block->prefix,
PAGE_SIZE);
return 0;
}
VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
viwhy);
return -ENOTSUPP;
}
static const intercept_handler_t intercept_funcs[0x48 >> 2] = {
[0x00 >> 2] = handle_noop,
[0x10 >> 2] = handle_noop,
[0x14 >> 2] = handle_noop,
[0x20 >> 2] = handle_validity,
[0x28 >> 2] = handle_stop,
};
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
{
intercept_handler_t func;
u8 code = vcpu->arch.sie_block->icptcode;
if (code & 3 || code > 0x48)
return -ENOTSUPP;
func = intercept_funcs[code >> 2];
if (func)
return func(vcpu);
return -ENOTSUPP;
}
......@@ -23,12 +23,17 @@
#include <asm/lowcore.h>
#include <asm/pgtable.h>
#include "kvm-s390.h"
#include "gaccess.h"
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "userspace_handled", VCPU_STAT(exit_userspace) },
{ "exit_validity", VCPU_STAT(exit_validity) },
{ "exit_stop_request", VCPU_STAT(exit_stop_request) },
{ "exit_external_request", VCPU_STAT(exit_external_request) },
{ "exit_external_interrupt", VCPU_STAT(exit_external_interrupt) },
{ NULL }
};
......@@ -380,6 +385,7 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
int rc;
sigset_t sigsaved;
vcpu_load(vcpu);
......@@ -389,7 +395,45 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
__vcpu_run(vcpu);
switch (kvm_run->exit_reason) {
case KVM_EXIT_S390_SIEIC:
vcpu->arch.sie_block->gpsw.mask = kvm_run->s390_sieic.mask;
vcpu->arch.sie_block->gpsw.addr = kvm_run->s390_sieic.addr;
break;
case KVM_EXIT_UNKNOWN:
case KVM_EXIT_S390_RESET:
break;
default:
BUG();
}
might_sleep();
do {
__vcpu_run(vcpu);
rc = kvm_handle_sie_intercept(vcpu);
} while (!signal_pending(current) && !rc);
if (signal_pending(current) && !rc)
rc = -EINTR;
if (rc == -ENOTSUPP) {
/* intercept cannot be handled in-kernel, prepare kvm-run */
kvm_run->exit_reason = KVM_EXIT_S390_SIEIC;
kvm_run->s390_sieic.icptcode = vcpu->arch.sie_block->icptcode;
kvm_run->s390_sieic.mask = vcpu->arch.sie_block->gpsw.mask;
kvm_run->s390_sieic.addr = vcpu->arch.sie_block->gpsw.addr;
kvm_run->s390_sieic.ipa = vcpu->arch.sie_block->ipa;
kvm_run->s390_sieic.ipb = vcpu->arch.sie_block->ipb;
rc = 0;
}
if (rc == -EREMOTE) {
/* intercept was handled, but userspace support is needed
* kvm_run has been prepared by the handler */
rc = 0;
}
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
......
......@@ -13,6 +13,13 @@
#ifndef ARCH_S390_KVM_S390_H
#define ARCH_S390_KVM_S390_H
#include <linux/kvm_host.h>
typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu);
#define VM_EVENT(d_kvm, d_loglevel, d_string, d_args...)\
do { \
debug_sprintf_event(d_kvm->arch.dbf, d_loglevel, d_string "\n", \
......
......@@ -101,6 +101,10 @@ struct sie_block {
struct kvm_vcpu_stat {
u32 exit_userspace;
u32 exit_external_request;
u32 exit_external_interrupt;
u32 exit_stop_request;
u32 exit_validity;
};
struct kvm_vcpu_arch {
......
......@@ -74,6 +74,7 @@ struct kvm_irqchip {
#define KVM_EXIT_INTR 10
#define KVM_EXIT_SET_TPR 11
#define KVM_EXIT_TPR_ACCESS 12
#define KVM_EXIT_S390_SIEIC 13
/* for KVM_RUN, returned by mmap(vcpu_fd, offset=0) */
struct kvm_run {
......@@ -138,6 +139,14 @@ struct kvm_run {
__u32 is_write;
__u32 pad;
} tpr_access;
/* KVM_EXIT_S390_SIEIC */
struct {
__u8 icptcode;
__u64 mask; /* psw upper half */
__u64 addr; /* psw lower half */
__u16 ipa;
__u32 ipb;
} s390_sieic;
/* Fix the size of the union. */
char padding[256];
};
......
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