From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from casper.infradead.org ([85.118.1.10]:48353 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752790AbaEIJ64 (ORCPT ); Fri, 9 May 2014 05:58:56 -0400 Message-ID: <1399629530.879.21.camel@i7.infradead.org> Subject: Re: [PATCH v2 4/5] iommu: Use dma_addr_t for IOVA arguments From: David Woodhouse To: Bjorn Helgaas Cc: Arnd Bergmann , linux-doc@vger.kernel.org, Greg Kroah-Hartman , Joerg Roedel , Randy Dunlap , Liviu Dudau , linux-kernel@vger.kernel.org, James Bottomley , linux-pci@vger.kernel.org Date: Fri, 09 May 2014 10:58:50 +0100 In-Reply-To: <20140508203053.GA14448@google.com> References: <20140506223250.17968.27054.stgit@bhelgaas-glaptop.roam.corp.google.com> <45161364.3Gyo1xJJLV@wuerfel> <20140508001814.GB4951@google.com> <15249748.Q2CaU9aBE9@wuerfel> <20140508203053.GA14448@google.com> Content-Type: multipart/signed; micalg="sha-1"; protocol="application/x-pkcs7-signature"; boundary="=-+3/AQo7mLt/O4xlonDPZ" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: --=-+3/AQo7mLt/O4xlonDPZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2014-05-08 at 14:30 -0600, Bjorn Helgaas wrote: > I doubt there would be a noticeable performance effect since these are > relatively low-frequency interfaces (map, unmap, report_fault),=20 That point of view makes me sad. There are people who care deeply about the performance of IOMMU API map/unmap. It isn't used *just* for virtual machines any more. See drivers/infiniband/hw/usnic/usnic_uiom.c for example. (Yes, they probably ought to be using SVM. But that's not going to happen on the current generation of hardware.) I also hold out *some* hope for consolidating the map/unmap functions for the IOMMU and DMA APIs at some point. The main difference is that the DMA API allocates an IOVA for itself, while the IOMMU API is given the bus address too. So we end up with duplicated map/unmap functions, *and* all the IOMMU drivers implementing their own IOVA allocator. I'd like to see if we can have a single IOVA allocator for the DMA API to use, and let IOMMU drivers implement *just* the IOMMU API style of map/unmap functions where they're *told* where to put it. Which is another reason I'm not quite ready to shrug and say that IOMMU API map/unmap performance is uninteresting. Although since it's predicated here by "on 32-bit systems", I'm not actually throwing my toys out of the pram... :) --=20 David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation --=-+3/AQo7mLt/O4xlonDPZ Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIISxDCCBjQw ggQcoAMCAQICAR4wDQYJKoZIhvcNAQEFBQAwfTELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxKTAn BgNVBAMTIFN0YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MB4XDTA3MTAyNDIxMDE1NVoX DTE3MTAyNDIxMDE1NVowgYwxCzAJBgNVBAYTAklMMRYwFAYDVQQKEw1TdGFydENvbSBMdGQuMSsw KQYDVQQLEyJTZWN1cmUgRGlnaXRhbCBDZXJ0aWZpY2F0ZSBTaWduaW5nMTgwNgYDVQQDEy9TdGFy dENvbSBDbGFzcyAxIFByaW1hcnkgSW50ZXJtZWRpYXRlIENsaWVudCBDQTCCASIwDQYJKoZIhvcN AQEBBQADggEPADCCAQoCggEBAMcJg8zOLdgasSmkLhOrlr6KMoOMpohBllVHrdRvEg/q6r8jR+EK 75xCGhR8ToREoqe7zM9/UnC6TS2y9UKTpT1v7RSMzR0t6ndl0TWBuUr/UXBhPk+Kmy7bI4yW4urC +y7P3/1/X7U8ocb8VpH/Clt+4iq7nirMcNh6qJR+xjOhV+VHzQMALuGYn5KZmc1NbJQYclsGkDxD z2UbFqE2+6vIZoL+jb9x4Pa5gNf1TwSDkOkikZB1xtB4ZqtXThaABSONdfmv/Z1pua3FYxnCFmdr /+N2JLKutIxMYqQOJebr/f/h5t95m4JgrM3Y/w7YX9d7YAL9jvN4SydHsU6n65cCAwEAAaOCAa0w ggGpMA8GA1UdEwEB/wQFMAMBAf8wDgYDVR0PAQH/BAQDAgEGMB0GA1UdDgQWBBRTcu2SnODaywFc fH6WNU7y1LhRgjAfBgNVHSMEGDAWgBROC+8apEBbpRdphzDKNGhD0EGu8jBmBggrBgEFBQcBAQRa MFgwJwYIKwYBBQUHMAGGG2h0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9jYTAtBggrBgEFBQcwAoYh aHR0cDovL3d3dy5zdGFydHNzbC5jb20vc2ZzY2EuY3J0MFsGA1UdHwRUMFIwJ6AloCOGIWh0dHA6 Ly93d3cuc3RhcnRzc2wuY29tL3Nmc2NhLmNybDAnoCWgI4YhaHR0cDovL2NybC5zdGFydHNzbC5j b20vc2ZzY2EuY3JsMIGABgNVHSAEeTB3MHUGCysGAQQBgbU3AQIBMGYwLgYIKwYBBQUHAgEWImh0 dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwNAYIKwYBBQUHAgEWKGh0dHA6Ly93d3cu c3RhcnRzc2wuY29tL2ludGVybWVkaWF0ZS5wZGYwDQYJKoZIhvcNAQEFBQADggIBAAqDCH14qywG XLhjjF6uHLkjd02hcdh9hrw+VUsv+q1eeQWB21jWj3kJ96AUlPCoEGZ/ynJNScWy6QMVQjbbMXlt UfO4n4bGGdKo3awPWp61tjAFgraLJgDk+DsSvUD6EowjMTNx25GQgyYJ5RPIzKKR9tQW8gGK+2+R HxkUCTbYFnL6kl8Ch507rUdPPipJ9CgJFws3kDS3gOS5WFMxcjO5DwKfKSETEPrHh7p5shuuNktv sv6hxHTLhiMKX893gxdT3XLS9OKmCv87vkINQcNEcIIoFWbP9HORz9v3vQwR4e3ksLc2JZOAFK+s sS5XMEoznzpihEP0PLc4dCBYjbvSD7kxgDwZ+Aj8Q9PkbvE9sIPP7ON0fz095HdThKjiVJe6vofq +n6b1NBc8XdrQvBmunwxD5nvtTW4vtN6VY7mUCmxsCieuoBJ9OlqmsVWQvifIYf40dJPZkk9YgGT zWLpXDSfLSplbY2LL9C9U0ptvjcDjefLTvqSFc7tw1sEhF0n/qpA2r0GpvkLRDmcSwVyPvmjFBGq Up/pNy8ZuPGQmHwFi2/14+xeSUDG2bwnsYJQG2EdJCB6luQ57GEnTA/yKZSTKI8dDQa8Sd3zfXb1 9mOgSF0bBdXbuKhEpuP9wirslFe6fQ1t5j5R0xi72MZ8ikMu1RQZKCyDbMwazlHiMIIGQjCCBSqg AwIBAgIDCdkyMA0GCSqGSIb3DQEBBQUAMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRD b20gTHRkLjErMCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYG A1UEAxMvU3RhcnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0EwHhcN MTQwNTA0MTczMDIyWhcNMTUwNTA0MjM0MTAxWjBdMRkwFwYDVQQNExAzODNCMTVkSHFQSUR0cDZO MRwwGgYDVQQDDBNkd213MkBpbmZyYWRlYWQub3JnMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZy YWRlYWQub3JnMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAy7K+t+REIdZGFUfgR8Io QrJ/VLZil9I00JcwqTo8BiGy1dqSIB2y923siya5SDKMh1YurtCPsX96cNzwPmmN2cs0MKeVPQWz iQhHk3uKcB6LvvS7pzTahRWMRmTyW3CH+RphRM9plvyClY23GEeEnpBnGz4GaJJiPcJjGgzyZ/tI q473pOlSrDPZnZk43vt/5CJN46nIZOZ2I+PzlgINI+EbiwsXVn3VohHB7nVTwGaRLk5oywGt8ZT7 tDdxn3BQ3inO1sr5MtkV1o2cHlenIC8mlU8nL/mrqqVve7Vib1YQUycW+Pj4CBYm4FTeuctAvNzK U/daeBclOZ8ofgQe2wIDAQABo4IC2TCCAtUwCQYDVR0TBAIwADALBgNVHQ8EBAMCBLAwHQYDVR0l BBYwFAYIKwYBBQUHAwIGCCsGAQUFBwMEMB0GA1UdDgQWBBRAjCSCV70BpLBeXge5DXi+mPhHTTAf BgNVHSMEGDAWgBRTcu2SnODaywFcfH6WNU7y1LhRgjAeBgNVHREEFzAVgRNkd213MkBpbmZyYWRl YWQub3JnMIIBTAYDVR0gBIIBQzCCAT8wggE7BgsrBgEEAYG1NwECAzCCASowLgYIKwYBBQUHAgEW Imh0dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwgfcGCCsGAQUFBwICMIHqMCcWIFN0 YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MAMCAQEagb5UaGlzIGNlcnRpZmljYXRlIHdh cyBpc3N1ZWQgYWNjb3JkaW5nIHRvIHRoZSBDbGFzcyAxIFZhbGlkYXRpb24gcmVxdWlyZW1lbnRz IG9mIHRoZSBTdGFydENvbSBDQSBwb2xpY3ksIHJlbGlhbmNlIG9ubHkgZm9yIHRoZSBpbnRlbmRl ZCBwdXJwb3NlIGluIGNvbXBsaWFuY2Ugb2YgdGhlIHJlbHlpbmcgcGFydHkgb2JsaWdhdGlvbnMu MDYGA1UdHwQvMC0wK6ApoCeGJWh0dHA6Ly9jcmwuc3RhcnRzc2wuY29tL2NydHUxLWNybC5jcmww gY4GCCsGAQUFBwEBBIGBMH8wOQYIKwYBBQUHMAGGLWh0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9z dWIvY2xhc3MxL2NsaWVudC9jYTBCBggrBgEFBQcwAoY2aHR0cDovL2FpYS5zdGFydHNzbC5jb20v Y2VydHMvc3ViLmNsYXNzMS5jbGllbnQuY2EuY3J0MCMGA1UdEgQcMBqGGGh0dHA6Ly93d3cuc3Rh cnRzc2wuY29tLzANBgkqhkiG9w0BAQUFAAOCAQEAWS2KNN7O3vZVtNHXVqgbmijeptKwt+8b6yiF wT3kJoywInPl5U+OeKRZfQKTHghM4Ohof6lF244ZMxhir/xp7l/zkZ/BUbxLwp6kIL27Gi5pgP4D KLnTZheQL9N5Yi/vMONxMWcpcW+ZNv5hnDCfEsfVcLXC8sNLPjx2ezfMIhSSPwBuJpmOun70te4E P0YBqjSalPfvc5fC5KgaYtqTDFwo9Mw25X5HHDC0r6BK5aNrF1nD/xYTX7cdvZZWl7cUApr4PCrn uI2DEn7OWQ/rY407ytV1c5pjvmuv/IT/ZUb/kXV6Q47UvrJp2Ifi2VhsBcnHHasKavjtRCmpDsGM rTCCBkIwggUqoAMCAQICAwnZMjANBgkqhkiG9w0BAQUFADCBjDELMAkGA1UEBhMCSUwxFjAUBgNV BAoTDVN0YXJ0Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNp Z25pbmcxODA2BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xp ZW50IENBMB4XDTE0MDUwNDE3MzAyMloXDTE1MDUwNDIzNDEwMVowXTEZMBcGA1UEDRMQMzgzQjE1 ZEhxUElEdHA2TjEcMBoGA1UEAwwTZHdtdzJAaW5mcmFkZWFkLm9yZzEiMCAGCSqGSIb3DQEJARYT ZHdtdzJAaW5mcmFkZWFkLm9yZzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMuyvrfk RCHWRhVH4EfCKEKyf1S2YpfSNNCXMKk6PAYhstXakiAdsvdt7IsmuUgyjIdWLq7Qj7F/enDc8D5p jdnLNDCnlT0Fs4kIR5N7inAei770u6c02oUVjEZk8ltwh/kaYUTPaZb8gpWNtxhHhJ6QZxs+BmiS Yj3CYxoM8mf7SKuO96TpUqwz2Z2ZON77f+QiTeOpyGTmdiPj85YCDSPhG4sLF1Z91aIRwe51U8Bm kS5OaMsBrfGU+7Q3cZ9wUN4pztbK+TLZFdaNnB5XpyAvJpVPJy/5q6qlb3u1Ym9WEFMnFvj4+AgW JuBU3rnLQLzcylP3WngXJTmfKH4EHtsCAwEAAaOCAtkwggLVMAkGA1UdEwQCMAAwCwYDVR0PBAQD AgSwMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDBDAdBgNVHQ4EFgQUQIwkgle9AaSwXl4H uQ14vpj4R00wHwYDVR0jBBgwFoAUU3Ltkpzg2ssBXHx+ljVO8tS4UYIwHgYDVR0RBBcwFYETZHdt dzJAaW5mcmFkZWFkLm9yZzCCAUwGA1UdIASCAUMwggE/MIIBOwYLKwYBBAGBtTcBAgMwggEqMC4G CCsGAQUFBwIBFiJodHRwOi8vd3d3LnN0YXJ0c3NsLmNvbS9wb2xpY3kucGRmMIH3BggrBgEFBQcC AjCB6jAnFiBTdGFydENvbSBDZXJ0aWZpY2F0aW9uIEF1dGhvcml0eTADAgEBGoG+VGhpcyBjZXJ0 aWZpY2F0ZSB3YXMgaXNzdWVkIGFjY29yZGluZyB0byB0aGUgQ2xhc3MgMSBWYWxpZGF0aW9uIHJl cXVpcmVtZW50cyBvZiB0aGUgU3RhcnRDb20gQ0EgcG9saWN5LCByZWxpYW5jZSBvbmx5IGZvciB0 aGUgaW50ZW5kZWQgcHVycG9zZSBpbiBjb21wbGlhbmNlIG9mIHRoZSByZWx5aW5nIHBhcnR5IG9i bGlnYXRpb25zLjA2BgNVHR8ELzAtMCugKaAnhiVodHRwOi8vY3JsLnN0YXJ0c3NsLmNvbS9jcnR1 MS1jcmwuY3JsMIGOBggrBgEFBQcBAQSBgTB/MDkGCCsGAQUFBzABhi1odHRwOi8vb2NzcC5zdGFy dHNzbC5jb20vc3ViL2NsYXNzMS9jbGllbnQvY2EwQgYIKwYBBQUHMAKGNmh0dHA6Ly9haWEuc3Rh cnRzc2wuY29tL2NlcnRzL3N1Yi5jbGFzczEuY2xpZW50LmNhLmNydDAjBgNVHRIEHDAahhhodHRw Oi8vd3d3LnN0YXJ0c3NsLmNvbS8wDQYJKoZIhvcNAQEFBQADggEBAFktijTezt72VbTR11aoG5oo 3qbSsLfvG+sohcE95CaMsCJz5eVPjnikWX0Ckx4ITODoaH+pRduOGTMYYq/8ae5f85GfwVG8S8Ke pCC9uxouaYD+Ayi502YXkC/TeWIv7zDjcTFnKXFvmTb+YZwwnxLH1XC1wvLDSz48dns3zCIUkj8A biaZjrp+9LXuBD9GAao0mpT373OXwuSoGmLakwxcKPTMNuV+RxwwtK+gSuWjaxdZw/8WE1+3Hb2W Vpe3FAKa+Dwq57iNgxJ+zlkP62ONO8rVdXOaY75rr/yE/2VG/5F1ekOO1L6yadiH4tlYbAXJxx2r Cmr47UQpqQ7BjK0xggNvMIIDawIBATCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2 BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMJ 2TIwCQYFKw4DAhoFAKCCAa8wGAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUx DxcNMTQwNTA5MDk1ODUwWjAjBgkqhkiG9w0BCQQxFgQUsc+pYTmXF4OVM9kX806lXtz/RW4wgaUG CSsGAQQBgjcQBDGBlzCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0Q29tIEx0ZC4x KzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2BgNVBAMTL1N0 YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMJ2TIwgacGCyqG SIb3DQEJEAILMYGXoIGUMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRDb20gTHRkLjEr MCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYGA1UEAxMvU3Rh cnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0ECAwnZMjANBgkqhkiG 9w0BAQEFAASCAQCpqhLDlFn9FPzroenu9GBQuV1ZA/e2N2ZrH2XzviyYAVccuM0rY0t1IlTST/S8 Pi4RbbLu6nQz9TsqlB/okDl2B8uohxvFzU2BSuNj/o5CFO2z/YfTFS9ma/qsrqzy8fPBDPj7CRXa N/MTCI7serOp0e2l0HTwhDfZOj9ZyRSnSdZb6KUaVkhJA790qlsMPfU3ms7rp6dYhQ4rSP0dtwpP VInIdOtwAlZeKnPDkhgaDKySoKnyES+1nw0VgUIK05+Ceyva1fa5z1lkU9YHvwCeltWFtu0XjU/D fWKxg54BwDouhRgpc0Rmm6oWl4v85SQZMGAQUy6L+hnofpI+VksOAAAAAAAA --=-+3/AQo7mLt/O4xlonDPZ--