From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f45.google.com (mail-ej1-f45.google.com [209.85.218.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80D88128398; Tue, 26 Mar 2024 02:38:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711420730; cv=none; b=RyY9d3El3qSWvypi1fVSeNb6HlrAB3mTWuk14nMc667imj8/8vZVMPCxMbr+LHyjmvZllO6+iCrsflJzLbCXV9EoQjeObleTU89lN9A5LaO9jtqYE8+6RUAdKU3OCbpNC51k67ryKV1s0Eyzg71gHi4uc80KrjyWyrsql7lek88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711420730; c=relaxed/simple; bh=in6c2v3xl19HUF11Ca5Ajl+w+Eugi73J4PwyZgpMS2k=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=QpKk+FMVqe1keMb0w7cveffYBTzd6/5com5wzY9tbvhMSeeqp8bVbyxT8+TTzQ4GVGUlMmORmEUw+Ux4FEGF97IbfQSqHV4BPMMJa1SBWRNWq0fCTGXDEe2XvaSF4rgRRZZKk2mbN+inEwYRn0JGMDr/zou1Y13+ovoYosB1ADM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Z9tdChCh; arc=none smtp.client-ip=209.85.218.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Z9tdChCh" Received: by mail-ej1-f45.google.com with SMTP id a640c23a62f3a-a46de423039so286711466b.0; Mon, 25 Mar 2024 19:38:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1711420727; x=1712025527; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=xvuTO++gksCL8fZc9rnTMteYbv8VDF4X35FDvigGhis=; b=Z9tdChCh4afgt/I360grf7kVaHb7bUG7ubWdfd0URRyl49F6kEV6TEBNIfxnLW8qpt SgyF5hsNFpmjtRJVolN35t+kAcWZlMX8K/1kROtfGjnuLzXTpkaXb1JGCuxh4cd11H6A Sb/kt/65HP23cG9J1jRyieGKZwHozFrF1uhDjldhEdda9r1c3hZ5wpiim69/Qr5rRUip GNcxU0rcEKSlT1dl/94r/g5maokc3dcoAuLVdXlQFH9LY7WXIS2PAuEJNz+Rjta7BIMl nYhPJactU3LbeT+s08P4SOFlnfwpz/EF4Ffif9GnPeIETGdlDsyFulXg+fatIRtDCdY5 whzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711420727; x=1712025527; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=xvuTO++gksCL8fZc9rnTMteYbv8VDF4X35FDvigGhis=; b=xEhwLEnG8k/9ZoMIpkQQb/wXf985uqlvxiQfwMPrhO7MzhnXXV2lXwrwaWPHrrmn/w 2Iik4cxPP8EuHl1xN4xq2Znc4k1Xlcl50v6rzZ9ZQU1cNtp0nzG2batyR9rU2p2Zl74s BJd7RbGBg5nWmfpsOWsprb/WyJ7i0g5P05li3xg004IcifTLguDaEFG7lVV03/ifeDg0 1LaOzoLxoxSQ8iy7Gwv8HO0ksVxZ5lEgijQl2Ym3mPaab15ncCkrbHXb96whgmilmMH0 E6gZXxK3O/SBjs6E9BuQeorHQZVWyqddCtkjc9p0KaGJ1/kN9pPBollCXSzYqeeZO8cp REqg== X-Forwarded-Encrypted: i=1; AJvYcCVYIx3O/m2gi8uT4AJChx2qGd5+Jz4V7JcG3qQ0TsONLSya/9yyo7xzBs/IR3Z5zRwEljmqh3HnoTq6iY/xJC1mbbgOTjR4wmmheO8uBIposQ6zAR2uUZZoIgygrwyup3q8l6y/6mefNCE= X-Gm-Message-State: AOJu0YwAKpXn1zPfOlGOSFFQQHLv8ESCo7gx0M4GaH0dEPjJ3O0KbEDz M2/VTfDx28PNrYw9nu48f/70JTcJKLTjGT06Nk3sazaaNXbQVqYCmNx66LNLtb+Am+Nj6PK5WGd oTYrKnprZSpfUXD3dnoOWSVmDY7o= X-Google-Smtp-Source: AGHT+IHOdLWyBfukeIVQCzdbwxRaGW3vVBOom0CaCVMlu32t8AKYWeJCkDsVov9mGGSIhvtfIDAySQLVgGHxvqfS2+Q= X-Received: by 2002:a05:6402:520a:b0:56c:d21:d919 with SMTP id s10-20020a056402520a00b0056c0d21d919mr5364774edd.34.1711420726461; Mon, 25 Mar 2024 19:38:46 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240322214801.319975-1-robdclark@gmail.com> In-Reply-To: From: Rob Clark Date: Mon, 25 Mar 2024 19:38:34 -0700 Message-ID: Subject: Re: [PATCH] drm/prime: Unbreak virtgpu dma-buf export To: Dominik Behr Cc: dri-devel@lists.freedesktop.org, Rob Clark , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Sumit Semwal , =?UTF-8?Q?Christian_K=C3=B6nig?= , Simon Ser , open list , "open list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b" , "moderated list:DMA BUFFER SHARING FRAMEWORK:Keyword:bdma_(?:buf|fence|resv)b" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable This is actually a bit concerning.. importing a host page backed buffer without guest mapping into a passthru device probably doesn't work and should be rejected earlier. I do think we should relax the restriction (either taking my patch or reverting the commit it fixes) until we work this out properly (because the original patch is a regression), but importing a buffer without guest pages into a passthru device can't possibly work properly. Maybe it works by chance if the host buffer is mapped to the guest, but that is not guaranteed. BR, -R On Mon, Mar 25, 2024 at 3:35=E2=80=AFPM Dominik Behr w= rote: > > It also fixes importing virtgpu blobs into real hardware, for instance am= dgpu for DRI_PRIME rendering. > > On Fri, Mar 22, 2024 at 2:48=E2=80=AFPM Rob Clark w= rote: >> >> From: Rob Clark >> >> virtgpu "vram" GEM objects do not implement obj->get_sg_table(). But >> they also don't use drm_gem_map_dma_buf(). In fact they may not even >> have guest visible pages. But it is perfectly fine to export and share >> with other virtual devices. >> >> Reported-by: Dominik Behr >> Fixes: 207395da5a97 ("drm/prime: reject DMA-BUF attach when get_sg_table= is missing") >> Signed-off-by: Rob Clark >> --- >> drivers/gpu/drm/drm_prime.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c >> index 7352bde299d5..64dd6276e828 100644 >> --- a/drivers/gpu/drm/drm_prime.c >> +++ b/drivers/gpu/drm/drm_prime.c >> @@ -582,7 +582,12 @@ int drm_gem_map_attach(struct dma_buf *dma_buf, >> { >> struct drm_gem_object *obj =3D dma_buf->priv; >> >> - if (!obj->funcs->get_sg_table) >> + /* >> + * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drive= rs >> + * that implement their own ->map_dma_buf() do not. >> + */ >> + if ((dma_buf->ops->map_dma_buf =3D=3D drm_gem_map_dma_buf) && >> + !obj->funcs->get_sg_table) >> return -ENOSYS; >> >> return drm_gem_pin(obj); >> -- >> 2.44.0 >>