From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0068C1ABEC5 for ; Thu, 27 Feb 2025 01:41:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740620486; cv=none; b=KN7KgoNrqWCiGeO9tHuKD5jd6E5/6GRvC8MZjAFuoVZSU9BMi2DhvlJQOmA4pMe6zME9CzOt+kxVSZ/nJiEjAmxrRFWlTDXOgHfBS604qOWMpxC3/RXLUGgC5IRoSMW+q54ZPHHspkfcXC27H3IS0ebCFozik9LFB3OUYGxn9yY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740620486; c=relaxed/simple; bh=Uh8v7nQ+Ir93Sl+r18zQm8iu7CgR5AwBCEP9ygizBTY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=DZHyd7flRwcklTtExci7RJib6rkUvh/7VU7sTKw9M7kHekjhzrVETVUPVi0bLv5Nwi7hfVqouSF9wSOeAIK1oitJ1vAJT2gq/lSiJvUNR9fF9Ty4USIjIZUPMwxJHs4DdbfCDv8hutoLvFiQDSX4niKOc3EcLERt0U0ngaDnuoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZYDIKWt0; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZYDIKWt0" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2233b154004so8732645ad.0 for ; Wed, 26 Feb 2025 17:41:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1740620483; x=1741225283; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=w6l9m6fqMlLq1/610gDj8nnv1xOjQhHIjHJq9ELM5lQ=; b=ZYDIKWt0a3DJh789OwAxCYpKnXq8f8tF3Qdfl9/FAUHBUyMmjnGH4LskoC6NGDGrFA /KFxQ0zbg1QWZq5Om9QW1C2RL8wotsX/wyqd2Y8Uv7DaB5yDOjrCjJpbMiN7UGvh4CB6 Sfp+w2B1zYjWTac8Rtq/0dia5XT2aiL9CUl802QljwRTBjUDqiu3wCyh7wVUZPJeJfg0 xwcBFjZ2X6vv4A7CQdxOAkPuR/hQ0qLnypas1VstZU3tbca+sb9ts/jZKITYRfuxVywQ Nwspw1LPwDZmjEHU33fnjDh4cfC0YUuuKpgRkkC6l6bHaTvLYBqzLct8nGH+KmmqsqH9 j1pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740620483; x=1741225283; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=w6l9m6fqMlLq1/610gDj8nnv1xOjQhHIjHJq9ELM5lQ=; b=ivr7SWuCtsIlLFka/j2XkUyPWge3OByiazLn5TeCqOvjUpUMz/wKWxSxprQys4nuNl z29oW6xdw2lkC3jUrdWzumug82h4NXzAYscMXiqJYxGw9T6LtyfpQJsS50AaYvZFe0qu JDKS+QUhgcmpNhQzbdZIczwJX40dXCAYy7ThU0ODDJbrUhwruU/WAOF1MAxQNw9R21Me mtyzIbvwsPRJ2/xlHSL3ZmQdGrn5hh2WbdfN/hsHdCpjcqbkdMXeDKT0pzDIyQHD3L0o EKNKbTm5C91GA+PkylJqhXD5+Eat4DfNg5VGE2scHM7ASZlP8hknBLk/GIHDBKF7dzQ3 3pvA== X-Forwarded-Encrypted: i=1; AJvYcCX+5JF/dW52pTQK1MFgnC10sPU5025ZIix7JojzC6kqmZoDsI52dL/96dHZYTzIW2WgxiI=@vger.kernel.org X-Gm-Message-State: AOJu0YxFugbMi3FFy/qf1PxMI/ZvngdQN6yMHXVohF0pD9wOlso82KfM ZIqiqN4D8GkEW8lHPGjSfIxyW6ZR+PjVv7fW4sAfXosFIYNMTZZeILozKiwyVJ83fw9agWGk3T+ 90A== X-Google-Smtp-Source: AGHT+IG7Q8fN8EDpqtDnTkX2BbBCR1zsNJUiVjHqyfD/MBJpG4F8JviC5cGF5Cwpg0N7gFMxU1nBPseGqls= X-Received: from pfop3.prod.google.com ([2002:a05:6a00:b43:b0:730:92d9:52e3]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e887:b0:220:faa2:c917 with SMTP id d9443c01a7336-22320208770mr95991285ad.34.1740620483177; Wed, 26 Feb 2025 17:41:23 -0800 (PST) Date: Wed, 26 Feb 2025 17:41:21 -0800 In-Reply-To: <20250227012712.3193063-2-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250227012712.3193063-1-yosry.ahmed@linux.dev> <20250227012712.3193063-2-yosry.ahmed@linux.dev> Message-ID: Subject: Re: [PATCH v2 1/6] x86/bugs: Move the X86_FEATURE_USE_IBPB check into callers From: Sean Christopherson To: Yosry Ahmed Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Pawan Gupta , Andy Lutomirski , Peter Zijlstra , Josh Poimboeuf , Paolo Bonzini , Jim Mattson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, Feb 27, 2025, Yosry Ahmed wrote: > indirect_branch_prediction_barrier() only performs the MSR write if > X86_FEATURE_USE_IBPB is set, using alternative_msr_write(). In > preparation for removing X86_FEATURE_USE_IBPB, move the feature check > into the callers so that they can be addressed one-by-one, and use > X86_FEATURE_IBPB instead to guard the MSR write. > > Signed-off-by: Yosry Ahmed > Acked-by: Josh Poimboeuf > --- Acked-by: Sean Christopherson