From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Summers, Stuart" Subject: Re: [PATCH] drm/i915: Fix off-by-one in looking up icl sseu slice Date: Tue, 28 May 2019 20:45:05 +0000 Message-ID: <841d0d2765421947fbbeeefc523fbd3cbb516da2.camel@intel.com> References: <20190528200655.11605-1-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0937319070==" Return-path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id B834F6E064 for ; Tue, 28 May 2019 20:45:07 +0000 (UTC) In-Reply-To: <20190528200655.11605-1-chris@chris-wilson.co.uk> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: "intel-gfx@lists.freedesktop.org" , "chris@chris-wilson.co.uk" List-Id: intel-gfx@lists.freedesktop.org --===============0937319070== Content-Language: en-US Content-Type: multipart/signed; micalg=sha-1; protocol="application/x-pkcs7-signature"; boundary="=-iN381GGucsxopA7qv1Vu" --=-iN381GGucsxopA7qv1Vu Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2019-05-28 at 21:06 +0100, Chris Wilson wrote: > We want the index corresponding to the set bit but fls() returns the > 1-index value. >=20 > Otherwise, we trigger the sanitycheck > intel_sseu_get_subslices:46 GEM_BUG_ON(slice >=3D sseu- > >max_slices) > when we look up the invalid slice. >=20 > The only remaining question then is just how reliable the rest of > intel_calculate_mcr_s_ss_select() is -- how many more of those fls() > are > also off-by-one. >=20 > Fixes: 1ac159e23c2c ("drm/i915: Expand subslice mask") > Fixes: 1e40d4aea57b ("drm/i915/cnl: Implement > WaProgramMgsrForCorrectSliceSpecificMmioReads") > Signed-off-by: Chris Wilson > Cc: Daniele Ceraolo Spurio > Cc: Lionel Landwerlin > Cc: Stuart Summers > Cc: Manasi Navare > --- > drivers/gpu/drm/i915/gt/intel_workarounds.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c > b/drivers/gpu/drm/i915/gt/intel_workarounds.c > index fbc853085809..485cd1c8ecc4 100644 > --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c > +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c > @@ -781,7 +781,7 @@ wa_init_mcr(struct drm_i915_private *i915, struct > i915_wa_list *wal) > * read FUSE3 for enabled L3 Bank IDs, if L3 Bank > matches > * enabled subslice, no need to redirect MCR packet > */ > - u32 slice =3D fls(sseu->slice_mask); > + u32 slice =3D __fls(sseu->slice_mask); The condition around this (is_power_of_2) makes sure we meet the case where the slice_mask is uninitialized. This is going to work here, but might not work in all other places. If we propagate this change to the other places we call fls(slice_mask), which I'd recommend, we'll want to make sure we check for that. Once we show results in CI: Reviewed-by: Stuart Summers > u32 fuse3 =3D > intel_uncore_read(&i915->uncore, > GEN10_MIRROR_FUSE3); > u32 ss_mask =3D intel_sseu_get_subslices(sseu, slice); --=-iN381GGucsxopA7qv1Vu Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIKcTCCBOsw ggPToAMCAQICEDabxALowUBS+21KC0JI8fcwDQYJKoZIhvcNAQEFBQAwbzELMAkGA1UEBhMCU0Ux FDASBgNVBAoTC0FkZFRydXN0IEFCMSYwJAYDVQQLEx1BZGRUcnVzdCBFeHRlcm5hbCBUVFAgTmV0 d29yazEiMCAGA1UEAxMZQWRkVHJ1c3QgRXh0ZXJuYWwgQ0EgUm9vdDAeFw0xMzEyMTEwMDAwMDBa Fw0yMDA1MzAxMDQ4MzhaMHkxCzAJBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEUMBIGA1UEBxMLU2Fu dGEgQ2xhcmExGjAYBgNVBAoTEUludGVsIENvcnBvcmF0aW9uMSswKQYDVQQDEyJJbnRlbCBFeHRl cm5hbCBCYXNpYyBJc3N1aW5nIENBIDRCMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA yzuW/y/g0bznz8BD48M94luFzqHaqY9yGN9H/W0J7hOVBpl0rTQJ6kZ7z7hyDb9kf2UW4ZU25alC i+q5m6NwHg+z9pcN7bQ84SSBueaYF7cXlAg7z3XyZbzSEYP7raeuWRf5fYvYzq8/uI7VNR8o/43w PtDP10YDdO/0J5xrHxnC/9/aU+wTFSVsPqxsd7C58mnu7G4VRJ0n9PG4SfmYNC0h/5fLWuOWhxAv 6MuiK7MmvTPHLMclULgJqVSqG1MbBs0FbzoRHne4Cx0w6rtzPTrzo+bTRqhruaU18lQkzBk6OnyJ UthtaDQIlfyGy2IlZ5F6QEyjItbdKcHHdjBX8wIDAQABo4IBdzCCAXMwHwYDVR0jBBgwFoAUrb2Y ejS0Jvf6xCZU7wO94CTLVBowHQYDVR0OBBYEFNpBI5xaj3GvV4M+INPjZdsMywvbMA4GA1UdDwEB /wQEAwIBhjASBgNVHRMBAf8ECDAGAQH/AgEAMDYGA1UdJQQvMC0GCCsGAQUFBwMEBgorBgEEAYI3 CgMEBgorBgEEAYI3CgMMBgkrBgEEAYI3FQUwFwYDVR0gBBAwDjAMBgoqhkiG+E0BBQFpMEkGA1Ud HwRCMEAwPqA8oDqGOGh0dHA6Ly9jcmwudHJ1c3QtcHJvdmlkZXIuY29tL0FkZFRydXN0RXh0ZXJu YWxDQVJvb3QuY3JsMDoGCCsGAQUFBwEBBC4wLDAqBggrBgEFBQcwAYYeaHR0cDovL29jc3AudHJ1 c3QtcHJvdmlkZXIuY29tMDUGA1UdHgQuMCygKjALgQlpbnRlbC5jb20wG6AZBgorBgEEAYI3FAID oAsMCWludGVsLmNvbTANBgkqhkiG9w0BAQUFAAOCAQEAp9XGgH85hk/3IuN8F4nrFd24MAoau7Uq M/of09XtyYg2dV0TIPqtxPZw4813r78WwsGIbvtO8VQ18dNktIxaq6+ym2zebqDh0z6Bvo63jKE/ HMj8oNV3ovnuo+7rGpCppcda4iVBG2CetB3WXbUVr82EzECN+wxmC4H9Rup+gn+t+qeBTaXulQfV TYOvZ0eZPO+DyC2pVv5q5+xHljyUsVqpzsw89utuO8ZYaMsQGBRuFGOncRLEOhCtehy5B5aCI571 i4dDAv9LPODrEzm3PBfrNhlp8C0skak15VXWFzNuHd00AsxXxWSUT4TG8RiAH61Ua5GXsP1BIZwl 4WjK8DCCBX4wggRmoAMCAQICEzMAAHThOHejBjRRsRQAAAAAdOEwDQYJKoZIhvcNAQEFBQAweTEL MAkGA1UEBhMCVVMxCzAJBgNVBAgTAkNBMRQwEgYDVQQHEwtTYW50YSBDbGFyYTEaMBgGA1UEChMR SW50ZWwgQ29ycG9yYXRpb24xKzApBgNVBAMTIkludGVsIEV4dGVybmFsIEJhc2ljIElzc3Vpbmcg Q0EgNEIwHhcNMTkwMTIzMTcxMTA0WhcNMjAwMTE4MTcxMTA0WjBDMRgwFgYDVQQDEw9TdW1tZXJz LCBTdHVhcnQxJzAlBgkqhkiG9w0BCQEWGHN0dWFydC5zdW1tZXJzQGludGVsLmNvbTCCASIwDQYJ KoZIhvcNAQEBBQADggEPADCCAQoCggEBAL7LpY79h4eyLdxekwAblnyPAHSCaXvVTUmnPKxWXs9g VCcf7gjGg8qg/HLCwvgGKGqtVkn2EaCKd85rqklaTp07JciV6a77qodO0yOgyz96hRVuSFAIP0UQ TXP+PuVIfYuqNSSgh2x2HzJy2DzpG12ZMldy6r2zAa6ypWevjFp5+3/mscAVNAmSHnyj838uukd/ YwrFtEG2j5l/EoijzGMRFUD0tS5eD2y0WmRfmc4xkv1Qjr8AN3ogZr4arGr+rF2F4aakLmoDUCZk PwuHX1mRETAlwqXCZa6ba8eraUCltlCb/ZiEk9UFRVLjbLNPh9IYOi+sWkS6n5CovLKAqhMCAwEA AaOCAjMwggIvMB0GA1UdDgQWBBSgeYqvLV4nBaCUzAXLr0TeMJYR5zAfBgNVHSMEGDAWgBTaQSOc Wo9xr1eDPiDT42XbDMsL2zBlBgNVHR8EXjBcMFqgWKBWhlRodHRwOi8vd3d3LmludGVsLmNvbS9y ZXBvc2l0b3J5L0NSTC9JbnRlbCUyMEV4dGVybmFsJTIwQmFzaWMlMjBJc3N1aW5nJTIwQ0ElMjA0 Qi5jcmwwgZ8GCCsGAQUFBwEBBIGSMIGPMCIGCCsGAQUFBzABhhZodHRwOi8vb2NzcC5pbnRlbC5j b20vMGkGCCsGAQUFBzAChl1odHRwOi8vd3d3LmludGVsLmNvbS9yZXBvc2l0b3J5L2NlcnRpZmlj YXRlcy9JbnRlbCUyMEV4dGVybmFsJTIwQmFzaWMlMjBJc3N1aW5nJTIwQ0ElMjA0Qi5jcnQwCwYD VR0PBAQDAgeAMDwGCSsGAQQBgjcVBwQvMC0GJSsGAQQBgjcVCIbDjHWEmeVRg/2BKIWOn1OCkcAJ Z4HevTmV8EMCAWQCAQkwHwYDVR0lBBgwFgYIKwYBBQUHAwQGCisGAQQBgjcKAwwwKQYJKwYBBAGC NxUKBBwwGjAKBggrBgEFBQcDBDAMBgorBgEEAYI3CgMMME0GA1UdEQRGMESgKAYKKwYBBAGCNxQC A6AaDBhzdHVhcnQuc3VtbWVyc0BpbnRlbC5jb22BGHN0dWFydC5zdW1tZXJzQGludGVsLmNvbTAN BgkqhkiG9w0BAQUFAAOCAQEAfyIC7rzSi6S8O+sdH384K8zyeMRJnl6vR7whl9PuEat+BkKpoxHn jQ0SFyF/cyI4lH/n938Pm3/Ctq0Z5GTldX6hhxxcLAR0qbk6AQU0Cq2nYMlZfX4FUz3FRsazbjTW 1qObcvPRUAVScaa7SRGdensvbNV++pN1XqEdc++szxo58UzPaEgDlHIe2sEIVXnFkHnJv0ikRHG3 urcA1bdj7Rac7dJBeQOQMdZEGmrWWmmbJzvk3OmoK9tKN7wcErQSdlqyYOMLesPfa7YNyLFYEJQd CC/N7V8U9yFZx8akWREb8lJYDl9KypirEsufleiew26CWrwcbmdlldDCFS6/HDGCAhcwggITAgEB MIGQMHkxCzAJBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEUMBIGA1UEBxMLU2FudGEgQ2xhcmExGjAY BgNVBAoTEUludGVsIENvcnBvcmF0aW9uMSswKQYDVQQDEyJJbnRlbCBFeHRlcm5hbCBCYXNpYyBJ c3N1aW5nIENBIDRCAhMzAAB04Th3owY0UbEUAAAAAHThMAkGBSsOAwIaBQCgXTAYBgkqhkiG9w0B CQMxCwYJKoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0xOTA1MjgyMDQ1MDFaMCMGCSqGSIb3DQEJ BDEWBBQFBQL0mXDUd3T4AMfDxWuY5xo1lDANBgkqhkiG9w0BAQEFAASCAQBVV2UliMZMT5UqWvKv eF2kNVoXUEmAQqOYj5AuXaNAa9nNgfxE75TdUVAUa11nuFDBUsjiBpYGwTDp3Ooq5VqLTgOY+ucD JLCMMJx/K8FTsuEKCUcsCQaE78O+Z2rm5lENwl6HWZApPUGjmFa8LKuaiMQl5c5qpw9IbT3o+sLh NVE/ZvSdVd9iI9Y+IJjb/f7g9PfMr98cQSy/55chwN9pP5mNU2InGgOahlhXZDDIPRYvheUVjfQ6 r9KeWBaq3hjuYvw4/6rl4FNlH6Un1IjYW60ZQ/Qv3GliZ8CohTaO/3xeXFtLxXJWmsGCLQPHfjQf m7Q5o3d/SBPpAEPnhK4YAAAAAAAA --=-iN381GGucsxopA7qv1Vu-- --===============0937319070== Content-Type: text/plain; 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