[PATCH v11 05/19] KVM: s390: pv: usage counter instead of flag

Claudio Imbrenda
2022-06-03T06:57:41Z

Use the new protected_count field as a counter instead of the old
is_protected flag. This will be used in upcoming patches.

Increment the counter when a secure configuration is created, and
decrement it when it is destroyed. Previously the flag was set when the
set secure parameters UVC was performed.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
---
arch/s390/include/asm/mmu.h | 2 +-
arch/s390/include/asm/mmu_context.h | 2 +-
arch/s390/include/asm/pgtable.h | 2 +-
arch/s390/kvm/pv.c | 12 +++++++-----
4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h
index 82aae78e1315..1572b3634cdd 100644
--- a/arch/s390/include/asm/mmu.h
+++ b/arch/s390/include/asm/mmu.h
@@ -18,7 +18,7 @@ typedef struct {
unsigned long asce_limit;
unsigned long vdso_base;
/* The mmu context belongs to a secure guest. */
- atomic_t is_protected;
+ atomic_t protected_count;
/*
* The following bitfields need a down_write on the mm
* semaphore when they are written to. As they are only
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index c7937f369e62..2a38af5a00c2 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -26,7 +26,7 @@ static inline int init_new_context(struct task_struct *tsk,
INIT_LIST_HEAD(&mm->context.gmap_list);
cpumask_clear(&mm->context.cpu_attach_mask);
atomic_set(&mm->context.flush_count, 0);
- atomic_set(&mm->context.is_protected, 0);
+ atomic_set(&mm->context.protected_count, 0);
mm->context.gmap_asce = 0;
mm->context.flush_mm = 0;
#ifdef CONFIG_PGSTE
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index a397b072a580..f16403ba81ec 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -525,7 +525,7 @@ static inline int mm_has_pgste(struct mm_struct *mm)
static inline int mm_is_protected(struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
- if (unlikely(atomic_read(&mm->context.is_protected)))
+ if (unlikely(atomic_read(&mm->context.protected_count)))
return 1;
#endif
return 0;
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index bcbe10862f9f..f3134d79f8e1 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -166,7 +166,8 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
- atomic_set(&kvm->mm->context.is_protected, 0);
+ if (!cc)
+ atomic_dec(&kvm->mm->context.protected_count);
KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
/* Intended memory leak on "impossible" error */
@@ -208,11 +209,14 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
/* Outputs */
kvm->arch.pv.handle = uvcb.guest_handle;

+ atomic_inc(&kvm->mm->context.protected_count);
if (cc) {
- if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
+ if (uvcb.header.rc & UVC_RC_NEED_DESTROY) {
kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
- else
+ } else {
+ atomic_dec(&kvm->mm->context.protected_count);
kvm_s390_pv_dealloc_vm(kvm);
+ }
return -EIO;
}
kvm->arch.gmap->guest_handle = uvcb.guest_handle;
@@ -235,8 +239,6 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
*rrc = uvcb.header.rrc;
KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
*rc, *rrc);
- if (!cc)
- atomic_set(&kvm->mm->context.is_protected, 1);
return cc ? -EINVAL : 0;
}

--
2.36.1