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Subject[07/53] KVM: s390: Fix RUNNING flag misinterpretation
3.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Cornelia Huck <cornelia.huck@de.ibm.com>

commit 9e6dabeffd1d0ec2aa19aa076c4886067238d442 upstream.

CPUSTAT_RUNNING was implemented signifying that a vcpu is not stopped.
This is not, however, what the architecture says: RUNNING should be
set when the host is acting on the behalf of the guest operating
system.

CPUSTAT_RUNNING has been changed to be set in kvm_arch_vcpu_load()
and to be unset in kvm_arch_vcpu_put().

For signifying stopped state of a vcpu, a host-controlled bit has
been used and is set/unset basically on the reverse as the old
CPUSTAT_RUNNING bit (including pushing it down into stop handling
proper in handle_stop()).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/s390/include/asm/kvm_host.h | 2 +-
arch/s390/kvm/diag.c | 2 +-
arch/s390/kvm/intercept.c | 3 ++-
arch/s390/kvm/interrupt.c | 1 +
arch/s390/kvm/kvm-s390.c | 10 +++++++---
arch/s390/kvm/sigp.c | 6 +++---
6 files changed, 15 insertions(+), 9 deletions(-)

--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -47,7 +47,7 @@ struct sca_block {
#define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
#define KVM_PAGES_PER_HPAGE(x) (KVM_HPAGE_SIZE(x) / PAGE_SIZE)

-#define CPUSTAT_HOST 0x80000000
+#define CPUSTAT_STOPPED 0x80000000
#define CPUSTAT_WAIT 0x10000000
#define CPUSTAT_ECALL_PEND 0x08000000
#define CPUSTAT_STOP_INT 0x04000000
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -42,7 +42,7 @@ static int __diag_ipl_functions(struct k
return -EOPNOTSUPP;
}

- atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
+ atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -132,7 +132,6 @@ static int handle_stop(struct kvm_vcpu *
int rc = 0;

vcpu->stat.exit_stop_request++;
- atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
spin_lock_bh(&vcpu->arch.local_int.lock);
if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
@@ -149,6 +148,8 @@ static int handle_stop(struct kvm_vcpu *
}

if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
+ atomic_set_mask(CPUSTAT_STOPPED,
+ &vcpu->arch.sie_block->cpuflags);
vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
rc = -EOPNOTSUPP;
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -224,6 +224,7 @@ static void __do_deliver_interrupt(struc
offsetof(struct _lowcore, restart_psw), sizeof(psw_t));
if (rc == -EFAULT)
exception = 1;
+ atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
break;

case KVM_S390_PROGRAM_INT:
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -265,10 +265,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu
restore_fp_regs(&vcpu->arch.guest_fpregs);
restore_access_regs(vcpu->arch.guest_acrs);
gmap_enable(vcpu->arch.gmap);
+ atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
}

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
+ atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
gmap_disable(vcpu->arch.gmap);
save_fp_regs(&vcpu->arch.guest_fpregs);
save_access_regs(vcpu->arch.guest_acrs);
@@ -296,7 +298,9 @@ static void kvm_s390_vcpu_initial_reset(

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
- atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH | CPUSTAT_SM);
+ atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH |
+ CPUSTAT_SM |
+ CPUSTAT_STOPPED);
vcpu->arch.sie_block->ecb = 6;
vcpu->arch.sie_block->eca = 0xC1002001U;
vcpu->arch.sie_block->fac = (int) (long) facilities;
@@ -421,7 +425,7 @@ static int kvm_arch_vcpu_ioctl_set_initi
{
int rc = 0;

- if (atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_RUNNING)
+ if (!(atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_STOPPED))
rc = -EBUSY;
else {
vcpu->run->psw_mask = psw.mask;
@@ -494,7 +498,7 @@ rerun_vcpu:
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);

- atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
+ atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);

BUG_ON(vcpu->kvm->arch.float_int.local_int[vcpu->vcpu_id] == NULL);

--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -57,8 +57,8 @@ static int __sigp_sense(struct kvm_vcpu
spin_lock(&fi->lock);
if (fi->local_int[cpu_addr] == NULL)
rc = 3; /* not operational */
- else if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
- & CPUSTAT_RUNNING) {
+ else if (!(atomic_read(fi->local_int[cpu_addr]->cpuflags)
+ & CPUSTAT_STOPPED)) {
*reg &= 0xffffffff00000000UL;
rc = 1; /* status stored */
} else {
@@ -212,7 +212,7 @@ static int __sigp_set_prefix(struct kvm_

spin_lock_bh(&li->lock);
/* cpu must be in stopped state */
- if (atomic_read(li->cpuflags) & CPUSTAT_RUNNING) {
+ if (!(atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
rc = 1; /* incorrect state */
*reg &= SIGP_STAT_INCORRECT_STATE;
kfree(inti);



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