From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 B6C6922538F for ; Sat, 7 Mar 2026 01:58:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772848722; cv=none; b=Mkecy/JpC5H57MxyBAVKmNI551Jhy65T9qqCILiroEf9yqr8TqfgB+OZhoNRHN10fAjvMWEUsx/e3lXfo3IFi+0mn0zjZo+D69F9lwGp44naX7bkkh0E3aZa3QIDJw7WsVGelKGAlKgwAO3XTUW03tuAhxQ6iz0vwoYp7zwA3Ko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772848722; c=relaxed/simple; bh=/3p7xZEybQEyoIPj8z7QKfOrsJvz2O+7OeYPPTzJFrQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=pl70fkF7zDie9NSl7Us+L3Bu7cdZfWTxMVvvY9dPD35yEiWCWMK0ORYUghR8KEX9JV+jnolH3JwBLZokWeR3Yo3ILpht0nh9wdKHbxU4zZS2jccZy+uo4IUHu28OSJ56OnlseNASfbLFrcf8Da31o/CneEQJ/ir84nl/1l5J92c= 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=ZEXnUpct; arc=none smtp.client-ip=209.85.210.202 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="ZEXnUpct" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-829ad8a2896so1433085b3a.0 for ; Fri, 06 Mar 2026 17:58:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772848720; x=1773453520; 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=FJcj4qTONIol7UXFe/O3JWnAgsBTo4u6T1CUvhonsps=; b=ZEXnUpctj81/Eb6CcDNggf1IC9CR60l+3rxoyUeg4fEi8Vn5ixWTk0atoziTj8m8/T ZnA8ZCrIEMXWG02sI1BskLww8WxmeUvzTLcZ+QW4fyTeAf7+TslZVWXwojoKhC5e7EJL rBO6/YG3ZHFgCUmmZbwY6wXWk25R3MXO9gwE8Dqv3hrkidAYmIwcYRCpwXPqbJyLl6nK GcRhnskuzlKHWSMNTThSen9UQQmiVQC9GNeLAYLPZsI54lnYA82YjsXFM5eMUIspTN7p xiEhLt4BA9raKkisvHfSLiQa8JXJtx6KPrinoJGDwXWVfYl42sfJ3wO/7sQ+D2Aib9H7 mMTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772848720; x=1773453520; 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=FJcj4qTONIol7UXFe/O3JWnAgsBTo4u6T1CUvhonsps=; b=HDILOyGvWehXbDS1JoO3Dxy645jMGSvg07pi5oKS1+PfnkMCh3eNwGBDydkfgkiVwE XbjVWGVU4y4dCbvKCm22yi9Mw7AE+Pzr9QNmu9ZzimUaQMCeWwtTYRM1uuWBuOZSXs8i YwA55QvJpRCAuPaJb8GbjuoCjiuhaF7dBK/fHgor+g+5cRe/FZ+wpkXy8VagvZ+yB8rW HSCzg5uGtF5L0I+g7udeysJ+CPXgplBjmlgawNeAMRiTfBX0fDfFZlOzgqZOuAkSz+gb 2zxccf8uaiWT2sLvu1ROaheRXeNyOlujEmwpCO6VsYZaNqwn5IXLJNz7AyIRX0rAIVCE 4Kbw== X-Forwarded-Encrypted: i=1; AJvYcCXE6knhkLPBjF03Tcu/S4Besn57Dn4CVNqVyCLTjW275KWejfxlYMOX7ToCeTpA6kcqNJc=@vger.kernel.org X-Gm-Message-State: AOJu0Yw9vcPHUD1LZWk6gTtKoUQx+PyMAVtT30OPreeTSYYRQ+trqwCZ GKVCE/LQR6JuKuZ5ur2g/rnkmugjRgJZbsl920ZBX9ijSU9hsOCVrogTYZL6pnzo6LihDmqQewI U5WFXfw== X-Received: from pfcf9.prod.google.com ([2002:a05:6a00:2389:b0:824:b871:c7cb]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:1827:b0:829:6f37:158a with SMTP id d2e1a72fcca58-829a2e3f823mr4056095b3a.18.1772848719917; Fri, 06 Mar 2026 17:58:39 -0800 (PST) Date: Fri, 6 Mar 2026 17:58:38 -0800 In-Reply-To: <20260129063653.3553076-2-shivansh.dhiman@amd.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260129063653.3553076-1-shivansh.dhiman@amd.com> <20260129063653.3553076-2-shivansh.dhiman@amd.com> Message-ID: Subject: Re: [PATCH 1/7] KVM: SVM: Initialize FRED VMCB fields From: Sean Christopherson To: Shivansh Dhiman Cc: pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, xin@zytor.com, nikunj.dadhania@amd.com, santosh.shukla@amd.com Content-Type: text/plain; charset="us-ascii" On Thu, Jan 29, 2026, Shivansh Dhiman wrote: > From: Neeraj Upadhyay > > The upcoming AMD FRED (Flexible Return and Event Delivery) feature > introduces several new fields to the VMCB save area. These fields include > FRED-specific stack pointers (fred_rsp[0-3], fred_ssp[1-3]), stack level > tracking (fred_stklvls), and configuration (fred_config). > > Ensure that a vCPU starts with a clean and valid FRED state on > capable hardware. Also update the size of save areas of VMCB. > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index f4ccb3e66635..5cec971a1f5a 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -1110,6 +1110,16 @@ static void init_vmcb(struct kvm_vcpu *vcpu, bool init_event) > save->idtr.base = 0; > save->idtr.limit = 0xffff; > > + save->fred_rsp0 = 0; > + save->fred_rsp1 = 0; > + save->fred_rsp2 = 0; > + save->fred_rsp3 = 0; > + save->fred_stklvls = 0; > + save->fred_ssp1 = 0; > + save->fred_ssp2 = 0; > + save->fred_ssp3 = 0; > + save->fred_config = 0; Is this architecturally correct? I.e. are all the FRED MSRs zeroed on INIT?