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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CDB2C433F5 for ; Wed, 1 Jun 2022 00:54:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348837AbiFAAxz (ORCPT ); Tue, 31 May 2022 20:53:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229849AbiFAAxw (ORCPT ); Tue, 31 May 2022 20:53:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5975874DCD for ; Tue, 31 May 2022 17:53:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DB082614AD for ; Wed, 1 Jun 2022 00:53:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9ADDDC385A9; Wed, 1 Jun 2022 00:53:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654044829; bh=EQ7y3MecILqxCm4jEd/aUGty8mqg6Pqf5GSMHZ3CV4A=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=iT2Hr0gEyj9nwHnMgGrg5ZFexC2dH48t7hzBN1IDF9PAB6qUaRSinConRCTu8BtPE R1tuk/hLs/JgCcKEnZF5j9oLorGTg7DzoDSvFqO/vBKtO/JRHkeam7mqEoA2a+djs4 lKbMCzYh91dyRR5NW1X38ykgpdgx6O1b5QyzaXy7k0yyZYx/WtqiKC/ahl+i0FE+8W GtN/07/8TzuFpbJcmZTqbfjai2y1dAUNiTnch5ddRsKJIMmFMqsD4VF61FuxALvEZZ 9PkilrXJ03elxU2G0UwJs/nlGnXPscuyIx7TkTVve2azJnESxMwH6ccexp8qW2NAFK tbfL7jOR/49tg== Date: Tue, 31 May 2022 17:53:47 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@ubuntu-linux-20-04-desktop To: Oleksandr Tyshchenko cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Oleksandr Tyshchenko , Stefano Stabellini , Boris Ostrovsky , Juergen Gross , Julien Grall , "Michael S. Tsirkin" , Christoph Hellwig Subject: Re: [PATCH V3 7/8] xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices In-Reply-To: <1653944417-17168-8-git-send-email-olekstysh@gmail.com> Message-ID: References: <1653944417-17168-1-git-send-email-olekstysh@gmail.com> <1653944417-17168-8-git-send-email-olekstysh@gmail.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 May 2022, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko > > Use the presence of "iommus" property pointed to the IOMMU node with > recently introduced "xen,grant-dma" compatible as a clear indicator > of enabling Xen grant mappings scheme for that device and read the ID > of Xen domain where the corresponding backend is running. The domid > (domain ID) is used as an argument to the Xen grant mapping APIs. > > To avoid the deferred probe timeout which takes place after reusing > generic IOMMU device tree bindings (because the IOMMU device never > becomes available) enable recently introduced stub IOMMU driver by > selecting XEN_GRANT_DMA_IOMMU. > > Also introduce xen_is_grant_dma_device() to check whether xen-grant > DMA ops need to be set for a passed device. > > Remove the hardcoded domid 0 in xen_grant_setup_dma_ops(). > > Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini > --- > Changes RFC -> V1: > - new patch, split required changes from commit: > "[PATCH 4/6] virtio: Various updates to xen-virtio DMA ops layer" > - update checks in xen_virtio_setup_dma_ops() to only support > DT devices for now > - remove the "virtio,mmio" check from xen_is_virtio_device() > - remane everything according to the new naming scheme: > s/virtio/grant_dma > > Changes V1 -> V2: > - remove dev_is_pci() check in xen_grant_setup_dma_ops() > - remove EXPORT_SYMBOL_GPL(xen_is_grant_dma_device); > > Changes V2 -> V3: > - Stefano already gave his Reviewed-by, I dropped it due to the changes (significant) > - update commit description > - reuse generic IOMMU device tree bindings, select XEN_GRANT_DMA_IOMMU > to avoid the deferred probe timeout > --- > drivers/xen/Kconfig | 1 + > drivers/xen/grant-dma-ops.c | 48 ++++++++++++++++++++++++++++++++++++++------- > include/xen/xen-ops.h | 5 +++++ > 3 files changed, 47 insertions(+), 7 deletions(-) > > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 35d20d9..bfd5f4f 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -347,6 +347,7 @@ config XEN_VIRTIO > bool "Xen virtio support" > depends on VIRTIO > select XEN_GRANT_DMA_OPS > + select XEN_GRANT_DMA_IOMMU if OF > help > Enable virtio support for running as Xen guest. Depending on the > guest type this will require special support on the backend side > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > index 44659f4..6586152 100644 > --- a/drivers/xen/grant-dma-ops.c > +++ b/drivers/xen/grant-dma-ops.c > @@ -55,11 +55,6 @@ static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev) > * Such a DMA address is formed by using the grant reference as a frame > * number and setting the highest address bit (this bit is for the backend > * to be able to distinguish it from e.g. a mmio address). > - * > - * Note that for now we hard wire dom0 to be the backend domain. In order > - * to support any domain as backend we'd need to add a way to communicate > - * the domid of this backend, e.g. via Xenstore, via the PCI-device's > - * config space or DT/ACPI. > */ > static void *xen_grant_dma_alloc(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t gfp, > @@ -275,9 +270,26 @@ static const struct dma_map_ops xen_grant_dma_ops = { > .dma_supported = xen_grant_dma_supported, > }; > > +bool xen_is_grant_dma_device(struct device *dev) > +{ > + struct device_node *iommu_np; > + bool has_iommu; > + > + /* XXX Handle only DT devices for now */ > + if (!dev->of_node) > + return false; > + > + iommu_np = of_parse_phandle(dev->of_node, "iommus", 0); > + has_iommu = iommu_np && of_device_is_compatible(iommu_np, "xen,grant-dma"); > + of_node_put(iommu_np); > + > + return has_iommu; > +} > + > void xen_grant_setup_dma_ops(struct device *dev) > { > struct xen_grant_dma_data *data; > + struct of_phandle_args iommu_spec; > > data = find_xen_grant_dma_data(dev); > if (data) { > @@ -285,12 +297,34 @@ void xen_grant_setup_dma_ops(struct device *dev) > return; > } > > + /* XXX ACPI device unsupported for now */ > + if (!dev->of_node) > + goto err; > + > + if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", > + 0, &iommu_spec)) { > + dev_err(dev, "Cannot parse iommus property\n"); > + goto err; > + } > + > + if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || > + iommu_spec.args_count != 1) { > + dev_err(dev, "Incompatible IOMMU node\n"); > + of_node_put(iommu_spec.np); > + goto err; > + } > + > + of_node_put(iommu_spec.np); > + > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > if (!data) > goto err; > > - /* XXX The dom0 is hardcoded as the backend domain for now */ > - data->backend_domid = 0; > + /* > + * The endpoint ID here means the ID of the domain where the corresponding > + * backend is running > + */ > + data->backend_domid = iommu_spec.args[0]; > > if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data, > GFP_KERNEL))) { > diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h > index 4f9fad5..62be9dc 100644 > --- a/include/xen/xen-ops.h > +++ b/include/xen/xen-ops.h > @@ -223,10 +223,15 @@ static inline void xen_preemptible_hcall_end(void) { } > > #ifdef CONFIG_XEN_GRANT_DMA_OPS > void xen_grant_setup_dma_ops(struct device *dev); > +bool xen_is_grant_dma_device(struct device *dev); > #else > static inline void xen_grant_setup_dma_ops(struct device *dev) > { > } > +static inline bool xen_is_grant_dma_device(struct device *dev) > +{ > + return false; > +} > #endif /* CONFIG_XEN_GRANT_DMA_OPS */ > > #endif /* INCLUDE_XEN_OPS_H */ > -- > 2.7.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 77F97C433EF for ; Wed, 1 Jun 2022 00:55:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; 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Wed, 01 Jun 2022 00:53:52 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D39666149D; Wed, 1 Jun 2022 00:53:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9ADDDC385A9; Wed, 1 Jun 2022 00:53:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654044829; bh=EQ7y3MecILqxCm4jEd/aUGty8mqg6Pqf5GSMHZ3CV4A=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=iT2Hr0gEyj9nwHnMgGrg5ZFexC2dH48t7hzBN1IDF9PAB6qUaRSinConRCTu8BtPE R1tuk/hLs/JgCcKEnZF5j9oLorGTg7DzoDSvFqO/vBKtO/JRHkeam7mqEoA2a+djs4 lKbMCzYh91dyRR5NW1X38ykgpdgx6O1b5QyzaXy7k0yyZYx/WtqiKC/ahl+i0FE+8W GtN/07/8TzuFpbJcmZTqbfjai2y1dAUNiTnch5ddRsKJIMmFMqsD4VF61FuxALvEZZ 9PkilrXJ03elxU2G0UwJs/nlGnXPscuyIx7TkTVve2azJnESxMwH6ccexp8qW2NAFK tbfL7jOR/49tg== Date: Tue, 31 May 2022 17:53:47 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@ubuntu-linux-20-04-desktop To: Oleksandr Tyshchenko cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Oleksandr Tyshchenko , Stefano Stabellini , Boris Ostrovsky , Juergen Gross , Julien Grall , "Michael S. Tsirkin" , Christoph Hellwig Subject: Re: [PATCH V3 7/8] xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices In-Reply-To: <1653944417-17168-8-git-send-email-olekstysh@gmail.com> Message-ID: References: <1653944417-17168-1-git-send-email-olekstysh@gmail.com> <1653944417-17168-8-git-send-email-olekstysh@gmail.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220531_175350_754007_BE08B02A X-CRM114-Status: GOOD ( 41.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 31 May 2022, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko > > Use the presence of "iommus" property pointed to the IOMMU node with > recently introduced "xen,grant-dma" compatible as a clear indicator > of enabling Xen grant mappings scheme for that device and read the ID > of Xen domain where the corresponding backend is running. The domid > (domain ID) is used as an argument to the Xen grant mapping APIs. > > To avoid the deferred probe timeout which takes place after reusing > generic IOMMU device tree bindings (because the IOMMU device never > becomes available) enable recently introduced stub IOMMU driver by > selecting XEN_GRANT_DMA_IOMMU. > > Also introduce xen_is_grant_dma_device() to check whether xen-grant > DMA ops need to be set for a passed device. > > Remove the hardcoded domid 0 in xen_grant_setup_dma_ops(). > > Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini > --- > Changes RFC -> V1: > - new patch, split required changes from commit: > "[PATCH 4/6] virtio: Various updates to xen-virtio DMA ops layer" > - update checks in xen_virtio_setup_dma_ops() to only support > DT devices for now > - remove the "virtio,mmio" check from xen_is_virtio_device() > - remane everything according to the new naming scheme: > s/virtio/grant_dma > > Changes V1 -> V2: > - remove dev_is_pci() check in xen_grant_setup_dma_ops() > - remove EXPORT_SYMBOL_GPL(xen_is_grant_dma_device); > > Changes V2 -> V3: > - Stefano already gave his Reviewed-by, I dropped it due to the changes (significant) > - update commit description > - reuse generic IOMMU device tree bindings, select XEN_GRANT_DMA_IOMMU > to avoid the deferred probe timeout > --- > drivers/xen/Kconfig | 1 + > drivers/xen/grant-dma-ops.c | 48 ++++++++++++++++++++++++++++++++++++++------- > include/xen/xen-ops.h | 5 +++++ > 3 files changed, 47 insertions(+), 7 deletions(-) > > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 35d20d9..bfd5f4f 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -347,6 +347,7 @@ config XEN_VIRTIO > bool "Xen virtio support" > depends on VIRTIO > select XEN_GRANT_DMA_OPS > + select XEN_GRANT_DMA_IOMMU if OF > help > Enable virtio support for running as Xen guest. Depending on the > guest type this will require special support on the backend side > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > index 44659f4..6586152 100644 > --- a/drivers/xen/grant-dma-ops.c > +++ b/drivers/xen/grant-dma-ops.c > @@ -55,11 +55,6 @@ static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev) > * Such a DMA address is formed by using the grant reference as a frame > * number and setting the highest address bit (this bit is for the backend > * to be able to distinguish it from e.g. a mmio address). > - * > - * Note that for now we hard wire dom0 to be the backend domain. In order > - * to support any domain as backend we'd need to add a way to communicate > - * the domid of this backend, e.g. via Xenstore, via the PCI-device's > - * config space or DT/ACPI. > */ > static void *xen_grant_dma_alloc(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t gfp, > @@ -275,9 +270,26 @@ static const struct dma_map_ops xen_grant_dma_ops = { > .dma_supported = xen_grant_dma_supported, > }; > > +bool xen_is_grant_dma_device(struct device *dev) > +{ > + struct device_node *iommu_np; > + bool has_iommu; > + > + /* XXX Handle only DT devices for now */ > + if (!dev->of_node) > + return false; > + > + iommu_np = of_parse_phandle(dev->of_node, "iommus", 0); > + has_iommu = iommu_np && of_device_is_compatible(iommu_np, "xen,grant-dma"); > + of_node_put(iommu_np); > + > + return has_iommu; > +} > + > void xen_grant_setup_dma_ops(struct device *dev) > { > struct xen_grant_dma_data *data; > + struct of_phandle_args iommu_spec; > > data = find_xen_grant_dma_data(dev); > if (data) { > @@ -285,12 +297,34 @@ void xen_grant_setup_dma_ops(struct device *dev) > return; > } > > + /* XXX ACPI device unsupported for now */ > + if (!dev->of_node) > + goto err; > + > + if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", > + 0, &iommu_spec)) { > + dev_err(dev, "Cannot parse iommus property\n"); > + goto err; > + } > + > + if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || > + iommu_spec.args_count != 1) { > + dev_err(dev, "Incompatible IOMMU node\n"); > + of_node_put(iommu_spec.np); > + goto err; > + } > + > + of_node_put(iommu_spec.np); > + > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > if (!data) > goto err; > > - /* XXX The dom0 is hardcoded as the backend domain for now */ > - data->backend_domid = 0; > + /* > + * The endpoint ID here means the ID of the domain where the corresponding > + * backend is running > + */ > + data->backend_domid = iommu_spec.args[0]; > > if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data, > GFP_KERNEL))) { > diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h > index 4f9fad5..62be9dc 100644 > --- a/include/xen/xen-ops.h > +++ b/include/xen/xen-ops.h > @@ -223,10 +223,15 @@ static inline void xen_preemptible_hcall_end(void) { } > > #ifdef CONFIG_XEN_GRANT_DMA_OPS > void xen_grant_setup_dma_ops(struct device *dev); > +bool xen_is_grant_dma_device(struct device *dev); > #else > static inline void xen_grant_setup_dma_ops(struct device *dev) > { > } > +static inline bool xen_is_grant_dma_device(struct device *dev) > +{ > + return false; > +} > #endif /* CONFIG_XEN_GRANT_DMA_OPS */ > > #endif /* INCLUDE_XEN_OPS_H */ > -- > 2.7.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel