From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=85.214.250.239 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793622126; b=H4XHTd6HPgkWKCP/Fa6YtAPQbGDie3VuuncD5ogjUfoUtWPrJ+5rumYF6WmFYvtbZNT6 74TWOzVihAYGjYkzpATMQoedAGypfRWFtbHsASzlIHYAHECIQqzYT+Wnf+X9zWmoT1MKe B6hc+2j0IdYDRl5wyUtvpkUlTXQ+kN35j+cNVdKnVe4gt7WiMrM/m7FpQ/wf1lMnJ1to7 ll1UP40u0atjS8sP7fEeYcB4AgYfySAdSx9Y8NL9uGXiBTt62ku+HhlrexA8dzf6tZXPK +LgFrX2sJAx4MBFoSbM/NilBoLFEVjm0sCaHZXLNvqQC8euwpB6qYQjJANtwooMaC8g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793622126; h=DMARC-Filter:Received:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=5praovLmNMiloGLMSjvfeB53TP3rGZZiLQVrVPcBvW8=; b=QdxLiA14ZLI+ssn/iKrvAdWiiy6ixAq2vlHoH1GzWYLtSmgDFfVy7j7glWX98gEBlWTs rTF5Fdcm975JLJrHF6Q/OUAgO0HfFkoVx7vGS/zqFX/sfXl7iGcew7riVWK5uB9SpLe9R 8HZQQRLxN6CpU2++XoOM9O88KUT4A1tHdUnTKko/PmU88sJbDIWQdu0mP0ZreCsFxSFvJ HEeHGrXWrqAlMZ5BlG+etu5u53B1Ivs5vUGZXSMgrzqin/uz6cFGhCPcNC8gz4BiWMBMJ Jv98cqPfUePiMgfUcMlrYiK/IGy5Vvl+at0LMVtwU7yefWOFANRYmct0uddUA1jdwQA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=8bytes.org; spf=pass smtp.mailfrom=8bytes.org; arc=none smtp.remote-ip=85.214.250.239 Received: from mail.8bytes.org (mail.8bytes.org [85.214.250.239]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E1AD0606AA0A for ; Mon, 2 Nov 2026 12:22:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E1AD0606AA0A Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=8bytes.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=8bytes.org Received: from 8bytes.org (p200300f6af404a0027ad06761c59e6b3.dip0.t-ipconnect.de [IPv6:2003:f6:af40:4a00:27ad:676:1c59:e6b3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.8bytes.org (Postfix) with ESMTPSA id 7623F243716; Mon, 2 Nov 2026 13:22:04 +0100 (CET) Date: Mon, 2 Nov 2026 13:22:02 +0100 From: =?utf-8?B?SsO2cmcgUsO2ZGVs?= To: sashiko-reviews@lists.linux.dev Cc: kvm@vger.kernel.org Subject: Re: [PATCH v3 2/8] KVM: SVM: Implement GET_AP_APIC_IDS NAE event Message-ID: References: <20261102114137.1198982-1-joro@8bytes.org> <20261102114137.1198982-3-joro@8bytes.org> X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Nov 02, 2026 at 11:52:44AM +0000, sashiko-bot@kernel.org wrote: > [Severity: High] > As reported by Sashiko on v2 [1], GHCB_HV_FT_APIC_ID_LIST is added > unconditionally to GHCB_HV_FT_SUPPORTED and sev_handle_vmgexit() dispatches > SVM_VMGEXIT_GET_APIC_IDS to sev_snp_get_apic_ids() for all SEV-SNP guests > without host userspace opting in. > > When an SEV-SNP guest queries hypervisor features via GHCB_MSR_HV_FT_REQ in > sev_handle_vmgexit_msr_protocol() or SVM_VMGEXIT_HV_FEATURES in > sev_handle_vmgexit(), it will unconditionally observe GHCB_HV_FT_APIC_ID_LIST. > If a guest uses this feature and is migrated or restored onto a kernel without > SVM_VMGEXIT_GET_APIC_IDS support, guest execution will fail when invoking the > NAE event. > > Should this new guest-visible feature default to off and be gated behind a > capability via KVM_CHECK_EXTENSION and KVM_ENABLE_CAP so userspace can manage > feature exposure and live migration compatibility? No, this feature is for SEV-SNP guests only, which can not be live migrated. Live migration for SEV-SNP guests will be built on-top of this feature (among others).