Blade ward in 2024 now subtrack from attack roll instead of grant resistance for physical damage

now i have a question, it effect only one attack and the spell is dispel(like Guidance that effect only one roll) or effect all attack until the spell end?

Whenever a creature makes an attack roll against you before the spell ends, the attacker subtracts 1d4 from the attack roll

Jurmondur is correct; it affects all attacks against you for 1 minute (unless you lose concentration on the spell). It's also worth pointing out that the 2024 version of Guidance doesn't work that way anymore either; it also lasts for 1 minute and affects all relevant rolls during that time, not just one.