Re: [PATCH v3 2/9] Documentation: KVM: s390: Describe KVM_S390_MEMOP_F_CMPXCHG

On 11/18/22 05:17, Janis Schoetterl-Glausch wrote:

+For write accesses, the KVM_S390_MEMOP_F_CMPXCHG might be supported.
+In this case, instead of doing an unconditional write, the access occurs only
+if the target location contains the "size" byte long value pointed to by
+"old_p". This is performed as an atomic cmpxchg. "size" must be a power of two
+up to and including 16.
+The value at the target location is written to the location "old_p" points to.
+If the exchange did not take place because the target value doesn't match the
+old value KVM_S390_MEMOP_R_NO_XCHG is returned.
+The KVM_S390_MEMOP_F_CMPXCHG flag is supported if KVM_CAP_S390_MEM_OP_EXTENSION
+has bit 1 (i.e. bit with value 2) set.
 

Is KVM_S390_MEMOP_F_CMPXCHG supported with conditions (as you implied)?

-- 
An old man doll... just what I always wanted! - Clara