From nobody Tue Apr 23 19:13:55 2024 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 ARC-Seal: i=1; a=rsa-sha256; t=1596199189; cv=none; d=zohomail.com; s=zohoarc; b=OD0IAurJC8ap6rMCJEyJI2wQnPNn+zzY8o492SZIUAI/pGkZViHExGfeVHCe4hLqpDNipjU5+qF5Q0hx0P2LKL9Sg8cmRg0VmUbfkXRAkq1NXdChMmUusvvM6SXcLTqn6/KFG+I6SUHB33IGu8DMoABRf3pOXfgZ8ZaJK96Z1WM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1596199189; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=z2IY39FopPNWgEDc6LGpyAvx8fgxPmSJFUs3X+CwziI=; b=gkHSAbD0eQibWChzzpssx532CSwBJGbeIjmdGJlZG8wCjny+ccIYhxejMQeAi3zrx71k5m1g0QLD+tqj2rs55BVVpz/nlgcMYdgJ4tXlUSAH1DC5DNbydZhwN8Fk4EEiX2eFMkduw+5UnX0medhR36RCQakTZJjC/TlOv+0/Jyw= ARC-Authentication-Results: i=1; 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 Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1596199189906545.1475782916536; Fri, 31 Jul 2020 05:39:49 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UJy-0007T5-1L; Fri, 31 Jul 2020 12:39:34 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UJw-0007SZ-4K for xen-devel@lists.xenproject.org; Fri, 31 Jul 2020 12:39:32 +0000 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id e13c6308-d32a-11ea-abab-12813bfff9fa; Fri, 31 Jul 2020 12:39:31 +0000 (UTC) Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UJu-0001A8-Gz; Fri, 31 Jul 2020 12:39:30 +0000 Received: from host86-143-223-30.range86-143.btcentralplus.com ([86.143.223.30] helo=u2f063a87eabd5f.home) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k1UJu-0007EP-9l; Fri, 31 Jul 2020 12:39:30 +0000 X-Inumbo-ID: e13c6308-d32a-11ea-abab-12813bfff9fa DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=z2IY39FopPNWgEDc6LGpyAvx8fgxPmSJFUs3X+CwziI=; b=QgyL/2yvdHMIT/RvS5+x0seXrH jkEXLIHDeIgKtoc0gHI/Lx4mj+nsTsK3PZw4CkHP6Ih56vM5Q/RL6YROl6omiQfgGa6Dsein+2gEa 9JtcTfIFllo6Xi0HJO8qh74OYSyMsN6aEqoiN1ISiyULsP0eN8bL2O1atcQePU9E0HHY=; From: Paul Durrant To: xen-devel@lists.xenproject.org Subject: [PATCH v2 1/2] x86/hvm: set 'ipat' in EPT for special pages Date: Fri, 31 Jul 2020 13:39:25 +0100 Message-Id: <20200731123926.28970-2-paul@xen.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200731123926.28970-1-paul@xen.org> References: <20200731123926.28970-1-paul@xen.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Paul Durrant , Wei Liu , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Paul Durrant All non-MMIO ranges (i.e those not mapping real device MMIO regions) that map valid MFNs are normally marked MTRR_TYPE_WRBACK and 'ipat' is set. Hence when PV drivers running in a guest populate the BAR space of the Xen Platfo= rm PCI Device with pages such as the Shared Info page or Grant Table pages, accesses to these pages will be cachable. However, should IOMMU mappings be enabled be enabled for the guest then the= se accesses become uncachable. This has a substantial negative effect on I/O throughput of PV devices. Arguably PV drivers should bot be using BAR space= to host the Shared Info and Grant Table pages but it is currently commonplace = for them to do this and so this problem needs mitigation. Hence this patch makes sure the 'ipat' bit is set for any special page regardless of where in GFN space it is mapped. NOTE: Clearly this mitigation only applies to Intel EPT. It is not obvious that there is any similar mitigation possible for AMD NPT. Downstreams such as Citrix XenServer have been carrying a patch similar to this f= or several releases though. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- Cc: Andrew Cooper Cc: Wei Liu Cc: "Roger Pau Monn=C3=A9" --- xen/arch/x86/hvm/mtrr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c index 511c3be1c8..3ad813ed15 100644 --- a/xen/arch/x86/hvm/mtrr.c +++ b/xen/arch/x86/hvm/mtrr.c @@ -830,7 +830,8 @@ int epte_get_entry_emt(struct domain *d, unsigned long = gfn, mfn_t mfn, return MTRR_TYPE_UNCACHABLE; } =20 - if ( !is_iommu_enabled(d) && !cache_flush_permitted(d) ) + if ( (!is_iommu_enabled(d) && !cache_flush_permitted(d)) || + is_special_page(mfn_to_page(mfn)) ) { *ipat =3D 1; return MTRR_TYPE_WRBACK; --=20 2.20.1 From nobody Tue Apr 23 19:13:55 2024 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; 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Fri, 31 Jul 2020 05:39:56 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UK2-0007US-9P; Fri, 31 Jul 2020 12:39:38 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UK1-0007SZ-2z for xen-devel@lists.xenproject.org; Fri, 31 Jul 2020 12:39:37 +0000 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id e20d8a00-d32a-11ea-abab-12813bfff9fa; Fri, 31 Jul 2020 12:39:32 +0000 (UTC) Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1UJv-0001AE-Ey; Fri, 31 Jul 2020 12:39:31 +0000 Received: from host86-143-223-30.range86-143.btcentralplus.com ([86.143.223.30] helo=u2f063a87eabd5f.home) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k1UJv-0007EP-7I; Fri, 31 Jul 2020 12:39:31 +0000 X-Inumbo-ID: e20d8a00-d32a-11ea-abab-12813bfff9fa DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=33WYKKwbqm7tyWR7ZQeAbyiugZFV+VQYG8o2+fd9T2E=; b=AT7z8AETk7fkVZqKS7UO+hsCJU fzOgU5vqC5I6LkYpnZZnMSBHqHXb1wseDoos04sKdndp/JBUMB/D02qz9ZCZIsjMBJBaBog5LvWzE dnkSGk/CJrGcfCUyrrtd3iUoaHhbTfS9G3C5eL3zKBx7Ni37p05obmM0coNgCHuJGNS8=; From: Paul Durrant To: xen-devel@lists.xenproject.org Subject: [PATCH v2 2/2] x86/hvm: simplify 'mmio_direct' check in epte_get_entry_emt() Date: Fri, 31 Jul 2020 13:39:26 +0100 Message-Id: <20200731123926.28970-3-paul@xen.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200731123926.28970-1-paul@xen.org> References: <20200731123926.28970-1-paul@xen.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Paul Durrant , Wei Liu , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Paul Durrant Re-factor the code to take advantage of the fact that the APIC access page = is a 'special' page. Suggested-by: Jan Beulich Signed-off-by: Paul Durrant --- Cc: Jan Beulich Cc: Andrew Cooper Cc: Wei Liu Cc: "Roger Pau Monn=C3=A9" --- xen/arch/x86/hvm/mtrr.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c index 3ad813ed15..0992f05e8f 100644 --- a/xen/arch/x86/hvm/mtrr.c +++ b/xen/arch/x86/hvm/mtrr.c @@ -814,29 +814,22 @@ int epte_get_entry_emt(struct domain *d, unsigned lon= g gfn, mfn_t mfn, return -1; } =20 - if ( direct_mmio ) - { - if ( (mfn_x(mfn) ^ mfn_x(d->arch.hvm.vmx.apic_access_mfn)) >> orde= r ) - return MTRR_TYPE_UNCACHABLE; - if ( order ) - return -1; - *ipat =3D 1; - return MTRR_TYPE_WRBACK; - } - if ( !mfn_valid(mfn) ) { *ipat =3D 1; return MTRR_TYPE_UNCACHABLE; } =20 - if ( (!is_iommu_enabled(d) && !cache_flush_permitted(d)) || + if ( (!direct_mmio && !is_iommu_enabled(d) && !cache_flush_permitted(d= )) || is_special_page(mfn_to_page(mfn)) ) { *ipat =3D 1; return MTRR_TYPE_WRBACK; } =20 + if ( direct_mmio ) + return MTRR_TYPE_UNCACHABLE; + gmtrr_mtype =3D hvm_get_mem_pinned_cacheattr(d, _gfn(gfn), order); if ( gmtrr_mtype >=3D 0 ) { --=20 2.20.1