From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8628CC25B10 for ; Mon, 6 May 2024 12:42:28 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.717614.1119990 (Exim 4.92) (envelope-from ) id 1s3xfa-0006hS-Tm; Mon, 06 May 2024 12:42:14 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 717614.1119990; Mon, 06 May 2024 12:42:14 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1s3xfa-0006hL-Qn; Mon, 06 May 2024 12:42:14 +0000 Received: by outflank-mailman (input) for mailman id 717614; Mon, 06 May 2024 12:42:13 +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 1s3xfZ-0006hF-FG for xen-devel@lists.xenproject.org; Mon, 06 May 2024 12:42:13 +0000 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [2a00:1450:4864:20::332]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 0e8bcfa4-0ba6-11ef-b4bb-af5377834399; Mon, 06 May 2024 14:42:11 +0200 (CEST) Received: by mail-wm1-x332.google.com with SMTP id 5b1f17b1804b1-41c1b75ca31so13285125e9.2 for ; Mon, 06 May 2024 05:42:11 -0700 (PDT) Received: from localhost ([213.195.114.223]) by smtp.gmail.com with ESMTPSA id d10-20020a05600c3aca00b00418e4cc9de7sm19628689wms.7.2024.05.06.05.42.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 May 2024 05:42:10 -0700 (PDT) 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: 0e8bcfa4-0ba6-11ef-b4bb-af5377834399 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1714999330; x=1715604130; darn=lists.xenproject.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=q6S8tN0PqUfWdBDz4LYEnqY2T5KjG/5O0y44awgmZBk=; b=mA6fE7RQipQDTPBwzdhz1Ejc4htv5ML9LgNIWhARp5hqij+VgnF87IHQZMdiDwrlFQ H6P7NmND8Oi3NMg/yDhzySHwZFEjl9kUUNPXTsCgrW5pP+o3XMjQi4y4QyZ39SUg7NiZ 63uI3m6m/Rp+9EYpfYQGudCKYiPxSfTPRYIYo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714999330; x=1715604130; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=q6S8tN0PqUfWdBDz4LYEnqY2T5KjG/5O0y44awgmZBk=; b=P5lfrX8NzVAToQ0sJz1xvkqm8JkbSgWe3ZYgduWVDhx/Ki6rHdv1Y+oz/gajaLUeC3 Gq39BtekN74sLRH6m9Io45LvE3sYcOL4x0SawGHk30YRSMTSfKPHBW50IX/hS1f4RMa7 dH3qrs11xDSM8l8rc17nc977TjZeupYuchS32evxXi/BtaBWVXeRYC++tJ7xuEARDC9v sp7tsIrGKJbMEzBXMLthupxrrb9JgJcDz3h8G0Ppru9nHzHZYYkVkgh65//gkzcRvtll JdYJ9zHC25jB9kSv+uiZ7+M3vWODSMDALiN+b9hYgSA4Ax+gVKg9bvAfiJ/KNZM8/7wl 1nUw== X-Gm-Message-State: AOJu0YzGq2vuffyz5U+V1WYBwVuKOfto84u0vhcmoJwMiX4NNB0GYXFD ilyXnkzYQvPJ0wh0b4gSe4+gS1+fS+svyKjaIYb67MCTfZRrOc8F+Nm+TKWm0ng= X-Google-Smtp-Source: AGHT+IH9EKQc2r2CMZ2jiGPEoRkY88zsw2uViGhGuKiiPjYbA4remP977CoWSC3O6ec50nyxwUoWaA== X-Received: by 2002:a05:600c:4711:b0:41a:c170:701f with SMTP id v17-20020a05600c471100b0041ac170701fmr7637618wmo.38.1714999330380; Mon, 06 May 2024 05:42:10 -0700 (PDT) Date: Mon, 6 May 2024 14:42:09 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Kevin Tian , Paul Durrant Subject: Re: [PATCH v2 05/12] IOMMU: rename and re-type ats_enabled Message-ID: References: <64b028be-2197-4951-ae5b-32f9eabfa84a@suse.com> <7f11ca06-9bed-443b-9c79-0e62b71a1f96@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <7f11ca06-9bed-443b-9c79-0e62b71a1f96@suse.com> On Thu, Feb 15, 2024 at 11:15:39AM +0100, Jan Beulich wrote: > Make the variable a tristate, with (as done elsewhere) a negative value > meaning "default". Since all use sites need looking at, also rename it > to match our usual "opt_*" pattern. While touching it, also move it to > .data.ro_after_init. I guess I need to look at further patches, as given the feedback on the past version I think we agreed we want to set ATS unconditionally disabled by default, and hence I'm not sure I see the point of the tri-state if enabling ATS will require an explicit opt-in on the command line (ats=1). > The only place it retains boolean nature is pci_ats_device(), for now. > > In AMD code re-order conditionals to have the config space accesses > after (cheaper) flag checks. > > Signed-off-by: Jan Beulich > --- > In domain_context_mapping_one() I'm a little puzzled that translation > type is selected based on only IOMMU and global properties, i.e. not > taking the device itself into account. Is it maybe fine do set DEV_IOTLB unconditionally as long as the IOMMU supports it, and then let the device decide whether it wants to issue translated or non-translated requests depending on whether it supports (and enables) ATS? I think it would be best to limit this strictly to devices that have ATS enabled. > --- > v2: Re-base over new earlier patches. > > --- a/xen/drivers/passthrough/amd/iommu_cmd.c > +++ b/xen/drivers/passthrough/amd/iommu_cmd.c > @@ -282,7 +282,7 @@ void amd_iommu_flush_iotlb(u8 devfn, con > struct amd_iommu *iommu; > unsigned int req_id, queueid, maxpend; > > - if ( !ats_enabled ) > + if ( opt_ats <= 0 ) If having a tri-state is required, won't it be best to decide on a binary value at init time, so that runtime functions can handle opt_ats as a boolean? Otherwise we are open coding the default expectation of what -1 implies (disabled) in all use sites. > return; > > if ( !pci_ats_enabled(pdev->seg, pdev->bus, pdev->devfn) ) > @@ -340,7 +340,7 @@ static void _amd_iommu_flush_pages(struc > flush_command_buffer(iommu, 0); > } > > - if ( ats_enabled ) > + if ( opt_ats > 0 ) > { > amd_iommu_flush_all_iotlbs(d, daddr, order); > > --- a/xen/drivers/passthrough/amd/pci_amd_iommu.c > +++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c > @@ -119,7 +119,7 @@ static bool use_ats( > const struct amd_iommu *iommu, > const struct ivrs_mappings *ivrs_dev) > { > - return !ivrs_dev->block_ats && > + return opt_ats > 0 && !ivrs_dev->block_ats && > iommu_has_cap(iommu, PCI_CAP_IOTLB_SHIFT) && > pci_ats_device(iommu->seg, pdev->bus, pdev->devfn); > } > @@ -196,7 +196,7 @@ static int __must_check amd_iommu_setup_ > dte->sys_mgt = MASK_EXTR(ivrs_dev->device_flags, ACPI_IVHD_SYSTEM_MGMT); > > if ( use_ats(pdev, iommu, ivrs_dev) ) > - dte->i = ats_enabled; > + dte->i = true; Might be easier to just use: dte->i = use_ats(pdev, iommu, ivrs_dev); > > spin_unlock_irqrestore(&iommu->lock, flags); > > @@ -257,7 +257,7 @@ static int __must_check amd_iommu_setup_ > ACPI_IVHD_SYSTEM_MGMT)); > > if ( use_ats(pdev, iommu, ivrs_dev) ) > - ASSERT(dte->i == ats_enabled); > + ASSERT(dte->i); ASSERT(dte->i == use_ats(pdev, iommu, ivrs_dev)); > > spin_unlock_irqrestore(&iommu->lock, flags); > > --- a/xen/drivers/passthrough/ats.c > +++ b/xen/drivers/passthrough/ats.c > @@ -18,8 +18,8 @@ > #include > #include "ats.h" > > -bool __read_mostly ats_enabled; > -boolean_param("ats", ats_enabled); > +int8_t __ro_after_init opt_ats = -1; > +boolean_param("ats", opt_ats); > > int enable_ats_device(struct pci_dev *pdev, struct list_head *ats_list) > { > --- a/xen/drivers/passthrough/ats.h > +++ b/xen/drivers/passthrough/ats.h > @@ -22,7 +22,7 @@ > #define ATS_QUEUE_DEPTH_MASK 0x1f > #define ATS_ENABLE (1<<15) > > -extern bool ats_enabled; > +extern int8_t opt_ats; > > int enable_ats_device(struct pci_dev *pdev, struct list_head *ats_list); > void disable_ats_device(struct pci_dev *pdev); > @@ -43,7 +43,7 @@ static inline int pci_ats_enabled(int se > > static inline int pci_ats_device(int seg, int bus, int devfn) > { > - if ( !ats_enabled ) > + if ( !opt_ats ) > return 0; Can't you remove that check altogether now, since you are adding an opt_ats check to use_ats()? Thanks, Roger.