KVM: s390: pv: usage counter instead of flag

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>
Link: https://lore.kernel.org/r/20220628135619.32410-6-imbrenda@linux.ibm.com
Message-Id: <20220628135619.32410-6-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h
index 82aae78e13153ff4089be33c7ac04de5772c08c9..1572b3634cdd08166d839023890103e83828be49 100644 (file)
--- 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 c7937f369e622c381be00ac3c27c61e7fdde3b09..2a38af5a00c2df0baff5594a59635f7c86d01b0e 100644 (file)
--- 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 a397b072a580048d623dcb7c20edcbafb5844a44..f16403ba81ec915136c8e9a68c4022e41fc8397b 100644 (file)
--- 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 a556db3912a1d9fc53030a7b9f0c6f9477535599..59e0d53991134286a27afc580f24033d706a38a1 100644 (file)
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -167,7 +167,8 @@ 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 */
@@ -209,11 +210,14 @@ 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;
@@ -236,8 +240,6 @@ 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;
 }