[PATCH 1/3] kvm-s390: infrastructure to kick vcpus out of guest state - rebased

ehrhardt
2009-06-15T13:48:04Z

*updates to already applied version*
- ensure allocations (might_sleep) are out of atomic context
- centralize consumption of vcpu->request bits

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>
---

[diffstat]
include/asm/kvm_host.h | 2 +-
kvm/intercept.c | 10 ++++++----
kvm/kvm-s390.c | 7 +++----
kvm/kvm-s390.h | 16 +++++++++++++++-
kvm/sigp.c | 31 +++++++++++++++++++++----------
5 files changed, 46 insertions(+), 20 deletions(-)

Index: kvm/arch/s390/kvm/intercept.c
===================================================================
--- kvm.orig/arch/s390/kvm/intercept.c
+++ kvm/arch/s390/kvm/intercept.c
@@ -141,10 +141,12 @@ static int handle_stop(struct kvm_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_VCPUREQUEST_ON_STOP) {
+ vcpu->arch.local_int.action_bits &= ~ACTION_VCPUREQUEST_ON_STOP;
+ if (kvm_s390_handle_vcpu_requests(vcpu, VCPUREQUESTLVL_SIGP)) {
+ rc = SIE_INTERCEPT_CHECKREQUESTS;
+ vcpu->run->exit_reason = KVM_EXIT_INTR;
+ }
}

if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
Index: kvm/arch/s390/include/asm/kvm_host.h
===================================================================
--- kvm.orig/arch/s390/include/asm/kvm_host.h
+++ kvm/arch/s390/include/asm/kvm_host.h
@@ -182,7 +182,7 @@ struct kvm_s390_interrupt_info {
/* for local_interrupt.action_flags */
#define ACTION_STORE_ON_STOP (1<<0)
#define ACTION_STOP_ON_STOP (1<<1)
-#define ACTION_RELOADVCPU_ON_STOP (1<<2)
+#define ACTION_VCPUREQUEST_ON_STOP (1<<2)

struct kvm_s390_local_interrupt {
spinlock_t lock;
Index: kvm/arch/s390/kvm/kvm-s390.c
===================================================================
--- kvm.orig/arch/s390/kvm/kvm-s390.c
+++ kvm/arch/s390/kvm/kvm-s390.c
@@ -484,8 +484,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v

rerun_vcpu:
if (vcpu->requests)
- if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
- kvm_s390_vcpu_set_mem(vcpu);
+ kvm_s390_handle_vcpu_requests(vcpu, VCPUREQUESTLVL_VCPURUN);

/* verify, that memory has been registered */
if (!vcpu->arch.sie_block->gmslm) {
@@ -521,7 +520,7 @@ rerun_vcpu:
rc = kvm_handle_sie_intercept(vcpu);
} while (!signal_pending(current) && !rc);

- if (rc == SIE_INTERCEPT_RERUNVCPU)
+ if (rc == SIE_INTERCEPT_CHECKREQUESTS)
goto rerun_vcpu;

if (signal_pending(current) && !rc) {
@@ -710,7 +709,7 @@ int kvm_arch_set_memory_region(struct kv
&kvm->vcpus[i]->requests))
continue;
kvm_s390_inject_sigp_stop(kvm->vcpus[i],
- ACTION_RELOADVCPU_ON_STOP);
+ ACTION_VCPUREQUEST_ON_STOP);
}
}

Index: kvm/arch/s390/kvm/kvm-s390.h
===================================================================
--- kvm.orig/arch/s390/kvm/kvm-s390.h
+++ kvm/arch/s390/kvm/kvm-s390.h
@@ -25,7 +25,7 @@
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)
+#define SIE_INTERCEPT_CHECKREQUESTS (1<<0)
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu);

#define VM_EVENT(d_kvm, d_loglevel, d_string, d_args...)\
@@ -81,6 +81,20 @@ static inline void kvm_s390_vcpu_set_mem
up_read(&vcpu->kvm->slots_lock);
}

+/* interception levels from which handle vcpu requests can be called */
+#define VCPUREQUESTLVL_SIGP 1
+#define VCPUREQUESTLVL_VCPURUN 2
+static inline unsigned long kvm_s390_handle_vcpu_requests(struct kvm_vcpu *vcpu,
+ int level)
+{
+ BUG_ON(!level);
+
+ if (!vcpu->requests)
+ return 0;
+
+ return vcpu->requests;
+}
+
/* implemented in priv.c */
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);

Index: kvm/arch/s390/kvm/sigp.c
===================================================================
--- kvm.orig/arch/s390/kvm/sigp.c
+++ kvm/arch/s390/kvm/sigp.c
@@ -108,15 +108,9 @@ unlock:
return rc;
}

-static int __inject_sigp_stop(struct kvm_s390_local_interrupt *li, int action)
+static int __inject_sigp_stop(struct kvm_s390_local_interrupt *li, int action,
+ struct kvm_s390_interrupt_info *inti)
{
- struct kvm_s390_interrupt_info *inti;
-
- inti = kzalloc(sizeof(*inti), GFP_KERNEL);
- if (!inti)
- return -ENOMEM;
- inti->type = KVM_S390_SIGP_STOP;
-
spin_lock_bh(&li->lock);
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
@@ -133,11 +127,17 @@ static int __sigp_stop(struct kvm_vcpu *
{
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) {
@@ -145,7 +145,7 @@ static int __sigp_stop(struct kvm_vcpu *
goto unlock;
}

- rc = __inject_sigp_stop(li, action);
+ rc = __inject_sigp_stop(li, action, inti);

unlock:
spin_unlock(&fi->lock);
@@ -156,7 +156,18 @@ unlock:
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);
+ struct kvm_s390_interrupt_info *inti;
+ int rc;
+
+ inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+ if (!inti)
+ return -ENOMEM;
+ inti->type = KVM_S390_SIGP_STOP;
+
+ rc = __inject_sigp_stop(li, action, inti);
+ if (rc)
+ kfree(inti);
+ return rc;
}

static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)