From nobody Fri Oct 31 04:02:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=quarantine dis=quarantine) header.from=proton.me Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 174956673701536.00589267831867; Tue, 10 Jun 2025 07:45:37 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1011034.1389321 (Exim 4.92) (envelope-from ) id 1uP0E5-0000yP-T7; Tue, 10 Jun 2025 14:45:21 +0000 Received: by outflank-mailman (output) from mailman id 1011034.1389321; Tue, 10 Jun 2025 14:45:21 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uP0E5-0000yI-QN; Tue, 10 Jun 2025 14:45:21 +0000 Received: by outflank-mailman (input) for mailman id 1011034; Tue, 10 Jun 2025 14:45:20 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uP0E4-0000yC-Lu for xen-devel@lists.xenproject.org; Tue, 10 Jun 2025 14:45:20 +0000 Received: from mail-4316.protonmail.ch (mail-4316.protonmail.ch [185.70.43.16]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 86f99796-4609-11f0-b894-0df219b8e170; Tue, 10 Jun 2025 16:45:18 +0200 (CEST) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 86f99796-4609-11f0-b894-0df219b8e170 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1749566717; x=1749825917; bh=j8NChAoRRghHkw6bMdTgGH+7hSXGauASCqa0irGPmnE=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector: List-Unsubscribe:List-Unsubscribe-Post; b=igWk0BbFYPUYflBR7P2G83gBqaHtDuV8TBMtx+BcbgaBK0txXjenS+bQc5frpT0db yGMZFEQIP4El/tTlC937x3RRxUKcNTJWrHLyUdurp00u5LMU+LOGewogQWwKnrCWFf 5ztW81NrLauZqR/HcdDtLncA68QJi5x9cFVTm7rQx9jvtCqjO8EuzQ+1r/UqmD6F4W v0pmPeX40Ythl2mZDcQrB/i0lJs9dPx+XkLRincAfntnyeNiFCK2Qe5qvd3HPvwyq4 HitoELmBlCkqYYXrozXy4Lg1L8rf/GSHpvMhALjDZzVntvQIEf/aSnt5U/X/l5ybpT blI1pW0Nta+tA== Date: Tue, 10 Jun 2025 14:45:12 +0000 To: xen-devel@lists.xenproject.org From: dmkhn@proton.me Cc: andrew.cooper3@citrix.com, anthony.perard@vates.tech, jbeulich@suse.com, julien@xen.org, michal.orzel@amd.com, roger.pau@citrix.com, sstabellini@kernel.org, teddy.astie@vates.tech, dmukhin@ford.com Subject: [PATCH v7] xen/domain: rewrite emulation_flags_ok() Message-ID: <20250610144500.3176661-1-dmukhin@ford.com> Feedback-ID: 123220910:user:proton X-Pm-Message-ID: 15c94af66adda4f24e222cb211be6c59b2f8fe66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1749566737540116600 Content-Type: text/plain; charset="utf-8" From: Denis Mukhin Rewrite emulation_flags_ok() to simplify future modifications. No functional change intended. Signed-off-by: Denis Mukhin Reviewed-by: Roger Pau Monn=C3=A9 --- Changes since v6: - simplified checks for PV further Link to v6: https://lore.kernel.org/xen-devel/20250610004216.3012253-1-dmuk= hin@ford.com/ Link to CI: https://gitlab.com/xen-project/people/dmukhin/xen/-/pipelines/1= 862559089 --- xen/arch/x86/domain.c | 78 +++++++++++++++++++++++++++++++++---------- 1 file changed, 60 insertions(+), 18 deletions(-) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index 7536b6c871..fdbd064ebf 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -743,32 +743,74 @@ int arch_sanitise_domain_config(struct xen_domctl_cre= atedomain *config) return 0; } =20 +/* + * Verify that the domain's emulation flags resolve to a supported configu= ration. + * + * This ensures we only allow a known, safe subset of emulation combinatio= ns + * (for both functionality and security). Arbitrary mixes are likely to ca= use + * errors (e.g. null pointer dereferences). + * + * NB: use the internal X86_EMU_XXX symbols, not the public XEN_X86_EMU_XXX + * symbols. + */ static bool emulation_flags_ok(const struct domain *d, uint32_t emflags) { + enum { + CAP_PV =3D BIT(0, U), + CAP_HVM =3D BIT(1, U), + CAP_HWDOM =3D BIT(2, U), + CAP_DOMU =3D BIT(3, U), + }; + static const struct { + unsigned int caps; + uint32_t min; + uint32_t opt; + } configs[] =3D { +#ifdef CONFIG_PV + /* PV dom0 and domU */ + { + .caps =3D CAP_PV | CAP_HWDOM | CAP_DOMU, + .opt =3D X86_EMU_PIT, + }, +#endif /* #ifdef CONFIG_PV */ + +#ifdef CONFIG_HVM + /* PVH dom0 */ + { + .caps =3D CAP_HVM | CAP_HWDOM, + .min =3D X86_EMU_LAPIC | X86_EMU_IOAPIC | X86_EMU_VPCI, + }, + + /* PVH domU */ + { + .caps =3D CAP_HVM | CAP_DOMU, + .min =3D X86_EMU_LAPIC, + }, + + /* HVM domU */ + { + .caps =3D CAP_HVM | CAP_DOMU, + .min =3D X86_EMU_ALL & ~(X86_EMU_VPCI | X86_EMU_USE_PIRQ), + /* HVM PIRQ feature is user-selectable. */ + .opt =3D X86_EMU_USE_PIRQ, + }, +#endif /* #ifdef CONFIG_HVM */ + }; + unsigned int i; + unsigned int caps =3D (is_pv_domain(d) ? CAP_PV : CAP_HVM) | + (is_hardware_domain(d) ? CAP_HWDOM : CAP_DOMU); + #ifdef CONFIG_HVM /* This doesn't catch !CONFIG_HVM case but it is better than nothing */ BUILD_BUG_ON(X86_EMU_ALL !=3D XEN_X86_EMU_ALL); #endif =20 - if ( is_hvm_domain(d) ) - { - if ( is_hardware_domain(d) && - emflags !=3D (X86_EMU_VPCI | X86_EMU_LAPIC | X86_EMU_IOAPIC) ) - return false; - if ( !is_hardware_domain(d) && - /* HVM PIRQ feature is user-selectable. */ - (emflags & ~X86_EMU_USE_PIRQ) !=3D - (X86_EMU_ALL & ~(X86_EMU_VPCI | X86_EMU_USE_PIRQ)) && - emflags !=3D X86_EMU_LAPIC ) - return false; - } - else if ( emflags !=3D 0 && emflags !=3D X86_EMU_PIT ) - { - /* PV or classic PVH. */ - return false; - } + for ( i =3D 0; i < ARRAY_SIZE(configs); i++ ) + if ( (caps & configs[i].caps) =3D=3D caps && + (emflags & ~configs[i].opt) =3D=3D configs[i].min ) + return true; =20 - return true; + return false; } =20 void __init arch_init_idle_domain(struct domain *d) --=20 2.34.1