From nobody Fri Oct 31 17:53:14 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 1748891887258632.6285268720663; Mon, 2 Jun 2025 12:18:07 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1003774.1383394 (Exim 4.92) (envelope-from ) id 1uMAfL-0000Kv-G0; Mon, 02 Jun 2025 19:17:47 +0000 Received: by outflank-mailman (output) from mailman id 1003774.1383394; Mon, 02 Jun 2025 19:17:47 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uMAfL-0000Ko-Cl; Mon, 02 Jun 2025 19:17:47 +0000 Received: by outflank-mailman (input) for mailman id 1003774; Mon, 02 Jun 2025 19:17:46 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uMAfK-0000JS-I9 for xen-devel@lists.xenproject.org; Mon, 02 Jun 2025 19:17:46 +0000 Received: from mail-24418.protonmail.ch (mail-24418.protonmail.ch [109.224.244.18]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 43147dee-3fe6-11f0-a300-13f23c93f187; Mon, 02 Jun 2025 21:17:45 +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: 43147dee-3fe6-11f0-a300-13f23c93f187 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1748891864; x=1749151064; bh=uzDJxgN96Kqct/U5nq9L2/hSZ+SqbrgJbBHgdSzDlw8=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector:List-Unsubscribe:List-Unsubscribe-Post; b=N0t0Aeyiiu2xj4exQknK6b4bzlblBLK1kUHpxCissNgvb507Z4ngR7isvwZyedmZV jSLno16ODafAY5HmtbWfl/F4ZdZ3g9ryH6gAxzCGEPLvK15EpdpML3iVV6yJurcAJf 5qFi/JexUzkjoODs78uVrSOt7GP6NctREv7MkuQCpO9Xy60ROthvRmSOKWhMUIPVzr cLSv/DgjGFw8kt2ApZIguSy+aPHMDHNn8qZuxk6waXSA10Mb8Ih2/CB6S3gfqbGIyh mKOWvoKxELGmVE08DQ1uikGvpNMoQUuRwls2uccnLxDdGRNH8R0Pry+RobYQh/iH46 WNXst4DSGsf8g== Date: Mon, 02 Jun 2025 19:17:38 +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 v5 2/2] xen/domain: rewrite emulation_flags_ok() Message-ID: <20250602191717.148361-3-dmukhin@ford.com> In-Reply-To: <20250602191717.148361-1-dmukhin@ford.com> References: <20250602191717.148361-1-dmukhin@ford.com> Feedback-ID: 123220910:user:proton X-Pm-Message-ID: 9ead51012b322b3702c37d34c3ae7cb06b5d2c06 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1748891889777116600 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: Stefano Stabellini Reviewed-by: Teddy Astie --- Changes since v4: - updated commentaries - added Teddy's R-b, kept Stefano's R-b --- xen/arch/x86/domain.c | 91 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 73 insertions(+), 18 deletions(-) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index 0363ccb384..4f6670ce37 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -743,32 +743,87 @@ 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 */ + { + .caps =3D CAP_PV | CAP_DOMU, + .min =3D 0, + .opt =3D 0, + }, + + /* PV dom0 */ + { + .caps =3D CAP_PV | CAP_HWDOM, + .min =3D X86_EMU_PIT, + .opt =3D 0, + }, +#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, + .opt =3D 0, + }, + + /* 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, + }, + + /* PVH domU */ + { + .caps =3D CAP_HVM | CAP_DOMU, + .min =3D X86_EMU_LAPIC, + .opt =3D 0, + }, +#endif /* #ifdef CONFIG_HVM */ + }; + unsigned int i, caps =3D is_hardware_domain(d) ? CAP_HWDOM : CAP_DOMU; + + if ( is_pv_domain(d) ) + caps |=3D CAP_PV; + else if ( is_hvm_domain(d) ) + caps |=3D CAP_HVM; + #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 =3D=3D configs[i].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