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Subject[PATCH 14/48] KVM: s390: infrastructure to kick vcpus out of guest state
Date
From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

To ensure vcpu's come out of guest context in certain cases this patch adds a
s390 specific way to kick them out of guest context. Currently it kicks them
out to rerun the vcpu_run path in the s390 code, but the mechanism itself is
expandable and with a new flag we could also add e.g. kicks to userspace etc.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/s390/include/asm/kvm_host.h | 5 ++-
arch/s390/kvm/intercept.c | 12 ++++++--
arch/s390/kvm/kvm-s390.c | 5 +++
arch/s390/kvm/kvm-s390.h | 3 ++
arch/s390/kvm/sigp.c | 56 +++++++++++++++++++++++---------------
5 files changed, 54 insertions(+), 27 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 1cd02f6..0a784f6 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -182,8 +182,9 @@ struct kvm_s390_interrupt_info {
};

/* for local_interrupt.action_flags */
-#define ACTION_STORE_ON_STOP 1
-#define ACTION_STOP_ON_STOP 2
+#define ACTION_STORE_ON_STOP (1<<0)
+#define ACTION_STOP_ON_STOP (1<<1)
+#define ACTION_RELOADVCPU_ON_STOP (1<<2)

struct kvm_s390_local_interrupt {
spinlock_t lock;
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 98997cc..0732ab4 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -128,7 +128,7 @@ static int handle_noop(struct kvm_vcpu *vcpu)

static int handle_stop(struct kvm_vcpu *vcpu)
{
- int rc;
+ int rc = 0;

vcpu->stat.exit_stop_request++;
atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
@@ -141,12 +141,18 @@ static int handle_stop(struct kvm_vcpu *vcpu)
rc = -ENOTSUPP;
}

+ if (vcpu->arch.local_int.action_bits & ACTION_RELOADVCPU_ON_STOP) {
+ vcpu->arch.local_int.action_bits &= ~ACTION_RELOADVCPU_ON_STOP;
+ rc = SIE_INTERCEPT_RERUNVCPU;
+ vcpu->run->exit_reason = KVM_EXIT_INTR;
+ }
+
if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
rc = -ENOTSUPP;
- } else
- rc = 0;
+ }
+
spin_unlock_bh(&vcpu->arch.local_int.lock);
return rc;
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 90d9d1b..1d65f62 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -490,6 +490,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

vcpu_load(vcpu);

+rerun_vcpu:
/* verify, that memory has been registered */
if (!vcpu->kvm->arch.guest_memsize) {
vcpu_put(vcpu);
@@ -509,6 +510,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu->arch.sie_block->gpsw.addr = kvm_run->s390_sieic.addr;
break;
case KVM_EXIT_UNKNOWN:
+ case KVM_EXIT_INTR:
case KVM_EXIT_S390_RESET:
break;
default:
@@ -522,6 +524,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
rc = kvm_handle_sie_intercept(vcpu);
} while (!signal_pending(current) && !rc);

+ if (rc == SIE_INTERCEPT_RERUNVCPU)
+ goto rerun_vcpu;
+
if (signal_pending(current) && !rc)
rc = -EINTR;

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 748fee8..2072cd4 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -20,6 +20,8 @@

typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);

+/* negativ values are error codes, positive values for internal conditions */
+#define SIE_INTERCEPT_RERUNVCPU (1<<0)
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu);

#define VM_EVENT(d_kvm, d_loglevel, d_string, d_args...)\
@@ -50,6 +52,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
struct kvm_s390_interrupt *s390int);
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
+int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action);

/* implemented in priv.c */
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 0ef81d6..21897b0 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -1,7 +1,7 @@
/*
* sigp.c - handlinge interprocessor communication
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -9,6 +9,7 @@
*
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Christian Borntraeger <borntraeger@de.ibm.com>
+ * Christian Ehrhardt <ehrhardt@de.ibm.com>
*/

#include <linux/kvm.h>
@@ -107,46 +108,57 @@ unlock:
return rc;
}

-static int __sigp_stop(struct kvm_vcpu *vcpu, u16 cpu_addr, int store)
+static int __inject_sigp_stop(struct kvm_s390_local_interrupt *li, int action)
{
- struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
- struct kvm_s390_local_interrupt *li;
struct kvm_s390_interrupt_info *inti;
- int rc;
-
- if (cpu_addr >= KVM_MAX_VCPUS)
- return 3; /* not operational */

inti = kzalloc(sizeof(*inti), GFP_KERNEL);
if (!inti)
return -ENOMEM;
-
inti->type = KVM_S390_SIGP_STOP;

- spin_lock(&fi->lock);
- li = fi->local_int[cpu_addr];
- if (li == NULL) {
- rc = 3; /* not operational */
- kfree(inti);
- goto unlock;
- }
spin_lock_bh(&li->lock);
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
- if (store)
- li->action_bits |= ACTION_STORE_ON_STOP;
- li->action_bits |= ACTION_STOP_ON_STOP;
+ li->action_bits |= action;
if (waitqueue_active(&li->wq))
wake_up_interruptible(&li->wq);
spin_unlock_bh(&li->lock);
- rc = 0; /* order accepted */
+
+ return 0; /* order accepted */
+}
+
+static int __sigp_stop(struct kvm_vcpu *vcpu, u16 cpu_addr, int action)
+{
+ struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
+ struct kvm_s390_local_interrupt *li;
+ int rc;
+
+ if (cpu_addr >= KVM_MAX_VCPUS)
+ return 3; /* not operational */
+
+ spin_lock(&fi->lock);
+ li = fi->local_int[cpu_addr];
+ if (li == NULL) {
+ rc = 3; /* not operational */
+ goto unlock;
+ }
+
+ rc = __inject_sigp_stop(li, action);
+
unlock:
spin_unlock(&fi->lock);
VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x", cpu_addr);
return rc;
}

+int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action)
+{
+ struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
+ return __inject_sigp_stop(li, action);
+}
+
static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
{
int rc;
@@ -262,11 +274,11 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
break;
case SIGP_STOP:
vcpu->stat.instruction_sigp_stop++;
- rc = __sigp_stop(vcpu, cpu_addr, 0);
+ rc = __sigp_stop(vcpu, cpu_addr, ACTION_STOP_ON_STOP);
break;
case SIGP_STOP_STORE_STATUS:
vcpu->stat.instruction_sigp_stop++;
- rc = __sigp_stop(vcpu, cpu_addr, 1);
+ rc = __sigp_stop(vcpu, cpu_addr, ACTION_STORE_ON_STOP);
break;
case SIGP_SET_ARCH:
vcpu->stat.instruction_sigp_arch++;
--
1.6.3.3


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