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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC489C388F7 for ; Tue, 10 Nov 2020 11:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75CE920795 for ; Tue, 10 Nov 2020 11:01:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="bfvmF4Nw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729943AbgKJLBi (ORCPT ); Tue, 10 Nov 2020 06:01:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726280AbgKJLBh (ORCPT ); Tue, 10 Nov 2020 06:01:37 -0500 Received: from mail-ej1-x633.google.com (mail-ej1-x633.google.com [IPv6:2a00:1450:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD513C0613CF for ; Tue, 10 Nov 2020 03:01:36 -0800 (PST) Received: by mail-ej1-x633.google.com with SMTP id i19so16905457ejx.9 for ; Tue, 10 Nov 2020 03:01:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pYzTGdmao3xkzP8TbX0W6fWML7TKbE3rkepKbfvYVgE=; b=bfvmF4Nw9A0vYOntraEuaSFi/CRzlvPZGuXmJ5nFZm/Da7pYiNY+odyyVgGfnfc9np dCWLypaqgj5hzmHmizIuLK1yCwZSmVFXh9ifPUOjltjj0TiCn22fper+lFREcJJrzQaO 8Hqxv7TOSxmoa3CzWWDO36u8M8JK31lrPILfs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pYzTGdmao3xkzP8TbX0W6fWML7TKbE3rkepKbfvYVgE=; b=ORk+7Os6nsw+Pjqk1pOQ0/Qyou5lCq0+6GPgBHqBDcNPUYV6pbHHbmE3txpcSDt6W7 eUVpcMB/FcXJfvQGKSmJTHtzKrXNOuUhy2zcgusWNJyrfngLvDWrYLDFW0ZejfSUE6Tt A0rhESVWlbtlyzYgiO2h60MhF8FdsrEFB+1n1HyFHm0ulUbsxavx9KdlFWlEePpy6C+3 S+D+FkFbmHtMtcGXUBfrd2aihSKFjYrIS11zrqtLwS4n6O0pCb3QUZ8bDdMpuyWxotor bRLsE+xATb4Vp2SELiPl2nYyZpQb0xztFk+QI1nyyt6iHbNgeUQI3S3gFRMbZxP4srHa l0BQ== X-Gm-Message-State: AOAM532jj/BTsjjWjOWgmNAo6kCza/g7sB4SmKsUUF2clZY6GlI+eOqb 4IhFlokebTo5ROHctlmGC3gQfhL/rby9rPq4qAsLAg== X-Google-Smtp-Source: ABdhPJxvSd3SexSFwQsaGeXg6n8nPgkYa7kdlNtCDs6UpbNythCe4D/slSvMAcLzGootK2YDAMLDyRD0ee1b1FxuXmU= X-Received: by 2002:a17:906:d94:: with SMTP id m20mr19391674eji.279.1605006095351; Tue, 10 Nov 2020 03:01:35 -0800 (PST) MIME-Version: 1.0 References: <20201105060257.35269-1-vikas.gupta@broadcom.com> <20201105060257.35269-2-vikas.gupta@broadcom.com> <20201105000806.1df16656@x1.home> In-Reply-To: From: Vikas Gupta Date: Tue, 10 Nov 2020 16:31:23 +0530 Message-ID: Subject: Re: [RFC, v0 1/3] vfio/platform: add support for msi To: Auger Eric Cc: Alex Williamson , Cornelia Huck , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vikram Prakash Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="00000000000032b86305b3be9aea" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org --00000000000032b86305b3be9aea Content-Type: text/plain; charset="UTF-8" Hi Eric, On Mon, Nov 9, 2020 at 8:35 PM Auger Eric wrote: > > Hi Vikas, > > On 11/6/20 3:54 AM, Vikas Gupta wrote: > > Hi Alex, > > > > On Thu, Nov 5, 2020 at 12:38 PM Alex Williamson > > wrote: > >> > >> On Thu, 5 Nov 2020 11:32:55 +0530 > >> Vikas Gupta wrote: > >> > >>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > >>> index 2f313a238a8f..aab051e8338d 100644 > >>> --- a/include/uapi/linux/vfio.h > >>> +++ b/include/uapi/linux/vfio.h > >>> @@ -203,6 +203,7 @@ struct vfio_device_info { > >>> #define VFIO_DEVICE_FLAGS_AP (1 << 5) /* vfio-ap device */ > >>> #define VFIO_DEVICE_FLAGS_FSL_MC (1 << 6) /* vfio-fsl-mc device */ > >>> #define VFIO_DEVICE_FLAGS_CAPS (1 << 7) /* Info supports caps */ > >>> +#define VFIO_DEVICE_FLAGS_MSI (1 << 8) /* Device supports msi */ > >>> __u32 num_regions; /* Max region index + 1 */ > >>> __u32 num_irqs; /* Max IRQ index + 1 */ > >>> __u32 cap_offset; /* Offset within info struct of first cap */ > >> > >> This doesn't make any sense to me, MSIs are just edge triggered > >> interrupts to userspace, so why isn't this fully described via > >> VFIO_DEVICE_GET_IRQ_INFO? If we do need something new to describe it, > >> this seems incomplete, which indexes are MSI (IRQ_INFO can describe > >> that)? We also already support MSI with vfio-pci, so a global flag for > >> the device advertising this still seems wrong. Thanks, > >> > >> Alex > >> > > Since VFIO platform uses indexes for IRQ numbers so I think MSI(s) > > cannot be described using indexes. > > In the patch set there is no difference between MSI and normal > > interrupt for VFIO_DEVICE_GET_IRQ_INFO. > in vfio_platform_irq_init() we first iterate on normal interrupts using > get_irq(). Can't we add an MSI index at the end of this list with > vdev->irqs[i].count > 1 and set vdev->num_irqs accordingly? Yes, I think MSI can be added to the end of list with setting vdev->irqs[i].count > 1. I`ll consider changing in the next patch set. Thanks, Vikas > > Thanks > > Eric > > The patch set adds MSI(s), say as an extension, to the normal > > interrupts and handled accordingly. Do you see this is a violation? If > > yes, then we`ll think of other possible ways to support MSI for the > > platform devices. > > Macro VFIO_DEVICE_FLAGS_MSI can be changed to any other name if it > > collides with an already supported vfio-pci or if not necessary, we > > can remove this flag. > > > > Thanks, > > Vikas > > > --00000000000032b86305b3be9aea Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIIQPwYJKoZIhvcNAQcCoIIQMDCCECwCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg gg2UMIIE6DCCA9CgAwIBAgIOSBtqCRO9gCTKXSLwFPMwDQYJKoZIhvcNAQELBQAwTDEgMB4GA1UE CxMXR2xvYmFsU2lnbiBSb290IENBIC0gUjMxEzARBgNVBAoTCkdsb2JhbFNpZ24xEzARBgNVBAMT Ckdsb2JhbFNpZ24wHhcNMTYwNjE1MDAwMDAwWhcNMjQwNjE1MDAwMDAwWjBdMQswCQYDVQQGEwJC RTEZMBcGA1UEChMQR2xvYmFsU2lnbiBudi1zYTEzMDEGA1UEAxMqR2xvYmFsU2lnbiBQZXJzb25h bFNpZ24gMiBDQSAtIFNIQTI1NiAtIEczMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA 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