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Date: Tue, 6 Oct 2015 18:14:12 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Keith Busch <keith.busch@...el.com>
Cc: LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
linux-pci@...r.kernel.org, Jiang Liu <jiang.liu@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Dan Williams <dan.j.williams@...el.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Bryan Veal <bryan.e.veal@...el.com>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [RFC PATCHv2] x86/pci: Initial commit for new VMD device driver
Hi Keith,
I have a few comments scattered below.
On Thu, Oct 01, 2015 at 11:44:14AM -0600, Keith Busch wrote:
> The Intel Volume Management Device (VMD) is an integrated endpoint on the
> platform's PCIe root complex that acts as a host bridge to a secondary
> PCIe domain. BIOS can reassign one or more root ports to appear within
> a VMD domain instead of the primary domain.
>
> This driver enumerates and enables the domain using the root bus
> configuration interface provided by the PCI subsystem. The driver
> provides configuration space accessor functions (pci_ops), bus and
> memory resources, a chained MSI irq domain, irq_chip implementation,
> and dma operations necessary to support the domain through the VMD
> endpoint's interface.
>
> VMD routes I/O as follows:
>
> 1) Configuration Space: BAR 0 ("CFGBAR") of VMD provides the base
> address and size for configuration space register access to VMD-owned
> root ports. It works similarly to MMCONFIG for extended configuration
> space. Bus numbering is independent and does not conflict with the
> primary domain.
>
> 2) MMIO Space: BARs 2 and 4 ("MEMBAR1" and "MEMBAR2") of VMD provide the
> base address, size, and type for MMIO register access. These addresses
> are not translated by VMD hardware; they are simply reservations to be
> distributed to root ports' memory base/limit registers and subdivided
> among devices downstream.
>
> 3) DMA: To interact appropriately with IOMMU, the source ID DMA read
> and write requests are translated to the bus-device-function of the
> VMD endpoint. Otherwise, DMA operates normally without VMD-specific
> address translation.
>
> 4) Interrupts: Part of VMD's BAR 4 is reserved for VMD's MSI-X Table and
> PBA. MSIs from VMD domain devices and ports are remapped to appear if
> they were issued using one of VMD's MSI-X table entries. Each MSI and
> MSI-X addresses of VMD-owned devices and ports have a special format
> where the address refers specific entries in VMD's MSI-X table. As with
> DMA, the interrupt source id is translated to VMD's bus-device-function.
>
> The driver provides its own MSI and MSI-X configuration functions
> specific to how MSI messages are used within the VMD domain, and
> it provides an irq_chip for independent IRQ allocation and to relay
> interrupts from VMD's interrupt handler to the appropriate device
> driver's handler.
>
> 5) Errors: PCIe error message are intercepted by the root ports normally
> (e.g. AER), except with VMD, system errors (i.e. firmware first) are
> disabled by default. AER and hotplug interrupts are translated in the
> same way as endpoint interrupts.
>
> 6) VMD does not support INTx interrupts or IO ports. Devices or drivers
> requiring these features should either not be placed below VMD-owned
> root ports, or VMD should be disabled by BIOS for such endpoints.
>
> Contributers to this patch include:
>
> Artur Paszkiewicz <artur.paszkiewicz@...el.com>
> Bryan Veal <bryan.e.veal@...el.com>
> Jon Derrick <jonathan.derrick@...el.coM>
>
> Signed-off-by: Keith Busch <keith.busch@...el.com>
> ---
> v1 -> v2:
>
> The original RFC used custom x86_msi_ops to provide the VMD device
> specific interrupt setup. This was rejected in favor of a chained irq
> domain hierarchy, so this version provides that. While it tests out
> successfully in the limited capacity that I can test this, I honestly
> don't understand completely how this works, so thank you to Jiang Liu
> for the guidance!
>
> Perhaps I'm missing a callback, but I don't see how the driver can limit
> the number of irq's requested with the irq domain way. The allocation is
> done one at a time instead of at once, so the driver doesn't know at this
> level how many were originally requested. This isn't terrible as I can
> circle the irq's back to the beginning if they exceed VMD's MSI-x count.
>
> This version includes the DMA operations required if an IOMMU is
> used. That feature was omitted from the original RFC. The dma operations
> are set via a PCI "fixup" if the device is in a VMD provided domain.
>
> All this created a larger in-kernel dependency than before, and it is
> submitted as a single patch instead of a short series since it is all
> specific to this driver.
>
> arch/x86/Kconfig | 15 ++
> arch/x86/include/asm/vmd.h | 39 +++
> arch/x86/kernel/apic/msi.c | 74 ++++++
> arch/x86/pci/Makefile | 2 +
> arch/x86/pci/vmd.c | 594 ++++++++++++++++++++++++++++++++++++++++++++
> kernel/irq/chip.c | 1 +
> kernel/irq/irqdomain.c | 3 +
> 7 files changed, 728 insertions(+)
> create mode 100644 arch/x86/include/asm/vmd.h
> create mode 100644 arch/x86/pci/vmd.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 328c835..73df607 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2631,6 +2631,21 @@ config PMC_ATOM
> def_bool y
> depends on PCI
>
> +config HAVE_VMDDEV
> + bool
> +
> +config VMDDEV
> + depends on PCI && PCI_DOMAINS && PCI_MSI && GENERIC_MSI_IRQ_DOMAIN && IRQ_DOMAIN_HIERARCHY
> + tristate "Volume Management Device Driver"
> + default N
> + select HAVE_VMDDEV
> + ---help---
> + Adds support for the Intel Volume Manage Device (VMD). VMD is
> + a secondary PCI host bridge that allows PCI Express root ports,
> + and devices attached to them, to be removed from the default PCI
> + domain and placed within the VMD domain. If your system provides
> + one of these and has devices attached to it, say "Y".
> +
> source "net/Kconfig"
>
> source "drivers/Kconfig"
> diff --git a/arch/x86/include/asm/vmd.h b/arch/x86/include/asm/vmd.h
> new file mode 100644
> index 0000000..9d9b181
> --- /dev/null
> +++ b/arch/x86/include/asm/vmd.h
> @@ -0,0 +1,39 @@
> +#ifndef _ASM_X86_VMD_H
> +#define _ASM_X86_VMD_H
> +
> +#ifdef CONFIG_HAVE_VMDDEV
> +#include <linux/list.h>
> +struct vmd_irq_list;
> +
> +struct vmd_dev {
> + struct pci_dev *dev;
> +
> + spinlock_t cfg_lock;
> + char __iomem *cfgbar;
> +
> + int msix_count;
> + struct msix_entry *msix_entries;
> + struct vmd_irq_list *irqs;
> +
> + struct pci_sysdata sysdata;
> + struct pci_bus *bus;
> + struct irq_domain *irq_domain;
> +
> + struct list_head node;
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> + struct dma_map_ops dma_ops;
> +#endif
> +};
> +
> +struct irq_domain *arch_create_vmd_msi_irq_domain(struct pci_dev *dev,
> + const struct irq_domain_ops *domain_ops);
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> +void vmd_add_dma_device(struct vmd_dev *vmd);
> +void vmd_del_dma_device(struct vmd_dev *vmd);
> +#else
> +static void vmd_add_dma_device(struct vmd_dev *vmd) {}
> +static void vmd_del_dma_device(struct vmd_dev *vmd) {}
> +#endif
> +
> +#endif
> +#endif /* _ASM_X86_VMD_H */
> diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
> index 5f1feb6..92566cd 100644
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -22,6 +22,7 @@
> #include <asm/hw_irq.h>
> #include <asm/apic.h>
> #include <asm/irq_remapping.h>
> +#include <asm/vmd.h>
>
> static struct irq_domain *msi_default_domain;
>
> @@ -134,6 +135,79 @@ static struct msi_domain_info pci_msi_domain_info = {
> .handler_name = "edge",
> };
>
> +#ifdef CONFIG_HAVE_VMDDEV
> +static struct irq_chip pci_chained_msi_controller = {
> + .name = "PCI-MSI-chained",
> +};
> +
> +static struct msi_domain_info pci_chained_msi_domain_info = {
> + .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> + MSI_FLAG_PCI_MSIX,
> + .ops = &pci_msi_domain_ops,
> + .chip = &pci_chained_msi_controller,
> +};
> +
> +struct irq_domain *arch_create_vmd_msi_irq_domain(struct pci_dev *dev,
> + const struct irq_domain_ops *domain_ops)
> +{
> + int count = 0;
> + struct msi_desc *msi_desc;
> + struct irq_domain *vmd_irqdomain, *msi_irqdomain;
> +
> + if (!dev->msix_enabled)
> + return NULL;
> +
> + for_each_pci_msi_entry(msi_desc, dev)
> + count += msi_desc->nvec_used;
> + vmd_irqdomain = irq_domain_add_linear(NULL, count,
> + domain_ops, dev);
> + if (!vmd_irqdomain)
> + return NULL;
> + msi_irqdomain = pci_msi_create_irq_domain(NULL, &pci_chained_msi_domain_info,
> + vmd_irqdomain);
> + if (!msi_irqdomain)
> + irq_domain_remove(vmd_irqdomain);
> + return msi_irqdomain;
> +}
> +EXPORT_SYMBOL_GPL(arch_create_vmd_msi_irq_domain);
> +
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> +DEFINE_SPINLOCK(vmd_dev_list_lock);
> +LIST_HEAD(vmd_dma_list);
> +
> +static void vmd_dma_set_ops(struct pci_dev *pdev)
> +{
> + struct vmd_dev *vmd;
> +
> + spin_lock(&vmd_dev_list_lock);
> + list_for_each_entry(vmd, &vmd_dma_list, node) {
> + if (pci_domain_nr(pdev->bus) == vmd->sysdata.domain) {
> + pdev->dev.archdata.dma_ops = &vmd->dma_ops;
> + break;
> + }
> + }
> + spin_unlock(&vmd_dev_list_lock);
> +}
> +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, vmd_dma_set_ops);
This seems like sort of a sledgehammer approach. We already have five
different places where we set up dev->archdata.dma_ops, and this adds
a sixth:
pci_device_add
of_pci_dma_configure
of_dma_configure
arch_setup_dma_ops
dev->archdata.dma_ops = ... # (1) arm64
pcibios_add_device
pcibios_setup_device
set_dma_ops
dev->archdata.dma_ops = ... # (2) powerpc
device_add
platform_notify
acpi_platform_notify
acpi_bind_one
arch_setup_dma_ops
dev->archdata.dma_ops = ... # (3) arm64
pci_enable_device
pci_enable_device_flags
do_pci_enable_device
pcibios_enable_device
pcibios_plat_dev_init
dev->dev.archdata.dma_ops = ... # (4) mips
pci_fixup_device(pci_fixup_enable, dev)
vmd_dma_set_ops
pdev->dev.archdata.dma_ops = ... # (6) x86 VMD
calgary_init # (5) x86 (calgary)
for_each_pci_dev
dev->dev.archdata.dma_ops = ...
We can discard the Calgary approach; that is clearly wrong because it
doesn't work at all for hotplug. The pci_device_add() path seems to
be the winner, so I'd suggest doing something in pcibios_add_device().
I know it will still be a little ugly because there will be some
VMD-specific stuff in the x86 pcibios_add_device(). But somebody is
working on replacing some of the pcibios_*() interfaces with a set of
host bridge function pointers, and that could end up being a clean way
to handle this. You already have a struct pci_host_bridge for the VMD
device (allocated implicitly in pci_create_root_bus()), so we could
someday pass in VMD-specific host bridge ops that would do the setup.
> +
> +void vmd_add_dma_device(struct vmd_dev *vmd)
> +{
> + spin_lock(&vmd_dev_list_lock);
> + list_add(&vmd->node, &vmd_dma_list);
> + spin_unlock(&vmd_dev_list_lock);
> +}
> +EXPORT_SYMBOL_GPL(vmd_add_dma_device);
> +
> +void vmd_del_dma_device(struct vmd_dev *vmd)
> +{
> + spin_lock(&vmd_dev_list_lock);
> + list_del_init(&vmd->node);
> + spin_unlock(&vmd_dev_list_lock);
> +}
> +EXPORT_SYMBOL_GPL(vmd_del_dma_device);
> +#endif
> +#endif
> +
> void arch_init_msi_domain(struct irq_domain *parent)
> {
> if (disable_apic)
> diff --git a/arch/x86/pci/Makefile b/arch/x86/pci/Makefile
> index 5c6fc35..c204079 100644
> --- a/arch/x86/pci/Makefile
> +++ b/arch/x86/pci/Makefile
> @@ -23,6 +23,8 @@ obj-y += bus_numa.o
> obj-$(CONFIG_AMD_NB) += amd_bus.o
> obj-$(CONFIG_PCI_CNB20LE_QUIRK) += broadcom_bus.o
>
> +obj-$(CONFIG_VMDDEV) += vmd.o
> +
> ifeq ($(CONFIG_PCI_DEBUG),y)
> EXTRA_CFLAGS += -DDEBUG
> endif
> diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c
> new file mode 100644
> index 0000000..63b5a90
> --- /dev/null
> +++ b/arch/x86/pci/vmd.c
> @@ -0,0 +1,594 @@
> +/*
> + * Volume Management Device driver
> + * Copyright (c) 2015, Intel Corporation.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <asm/irqdomain.h>
> +#include <asm/hpet.h>
> +#include <asm/msidef.h>
> +#include <asm/vmd.h>
> +
> +struct vmd_irq {
> + struct list_head node;
> + struct vmd_irq_list *irq;
> + unsigned int virq;
> +};
> +
> +struct vmd_irq_list {
> + struct list_head irq_list;
> + spinlock_t irq_lock;
> + unsigned int vmd_vector;
> + unsigned int index;
> +};
> +
> +static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
> +{
> + return container_of(bus->sysdata, struct vmd_dev, sysdata);
> +}
> +
> +static void vmd_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
> +{
> + struct vmd_irq *vmdirq = data->chip_data;
> +
> + msg->address_hi = MSI_ADDR_BASE_HI;
> + msg->address_lo = MSI_ADDR_BASE_LO | MSI_ADDR_DEST_ID(vmdirq->irq->index);
> + msg->data = MSI_DATA_VECTOR(vmdirq->irq->vmd_vector);
> +}
> +
> +static void vmd_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
> +{
> + pci_write_msi_msg(data->irq, msg);
> +}
> +
> +/*
> + * Function is required when using irq hierarchy domains, but we don't have a
> + * good way to not create conflicts with other devices sharing the same vector.
> + */
> +int vmd_irq_set_affinity(struct irq_data *data, const struct cpumask *dest,
> + bool force)
> +{
> + return 0;
> +}
> +
> +static struct irq_chip vmd_chip = {
> + .name = "VMD-MSI",
> + .irq_compose_msi_msg = vmd_msi_compose_msg,
> + .irq_write_msi_msg = vmd_msi_write_msg,
> + .irq_set_affinity = vmd_irq_set_affinity,
> +};
> +
> +static void vmd_msi_free_irqs(struct irq_domain *domain,
> + unsigned int virq, unsigned int nr_irqs)
> +{
> + struct vmd_irq *vmdirq;
> + struct irq_data *irq_data;
> +
> + irq_data = irq_domain_get_irq_data(domain, virq);
> + if (!irq_data)
> + return;
> + vmdirq = irq_data->chip_data;
> + kfree(vmdirq);
> +}
> +
> +static int vmd_msi_alloc_irqs(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *arg)
> +{
> + struct vmd_dev *vmd;
> + struct vmd_irq *vmdirq;
> + struct irq_data *irq_data;
> + struct pci_dev *dev = domain->host_data;
> +
> + irq_data = irq_domain_get_irq_data(domain, virq);
> + if (!irq_data)
> + return -EINVAL;
> +
> + vmd = pci_get_drvdata(dev);
> + if (!vmd)
> + return -EINVAL;
"vmd == NULL" is impossible, isn't it? If so, remove the test.
> +
> + vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);
> + if (!vmdirq)
> + return -ENOMEM;
> +
> + INIT_LIST_HEAD(&vmdirq->node);
> + vmdirq->irq = &vmd->irqs[virq % vmd->msix_count];
> + vmdirq->virq = virq;
> +
> + irq_domain_set_hwirq_and_chip(domain, virq, vmdirq->irq->vmd_vector, &vmd_chip, vmdirq);
> + irq_set_chip(virq, &vmd_chip);
> + irq_set_handler_data(virq, vmdirq);
> + __irq_set_handler(virq, handle_simple_irq, 0, NULL);
> +
> + return 0;
> +}
> +
> +static void vmd_msi_activate(struct irq_domain *domain,
> + struct irq_data *data)
> +{
> + unsigned long flags;
> + struct msi_msg msg;
> + struct vmd_irq *vmdirq = data->chip_data;
> + struct vmd_irq_list *irq = vmdirq->irq;
> +
> + BUG_ON(irq_chip_compose_msi_msg(data, &msg));
> + data->chip->irq_write_msi_msg(data, &msg);
> +
> + spin_lock_irqsave(&irq->irq_lock, flags);
> + list_add_tail(&vmdirq->node, &irq->irq_list);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> +}
> +
> +static void vmd_msi_deactivate(struct irq_domain *domain,
> + struct irq_data *data)
> +{
> + unsigned long flags;
> + struct msi_msg msg;
> + struct vmd_irq *vmdirq = data->chip_data;
> + struct vmd_irq_list *irq = vmdirq->irq;
> +
> + memset(&msg, 0, sizeof(msg));
> + data->chip->irq_write_msi_msg(data, &msg);
> +
> + spin_lock_irqsave(&irq->irq_lock, flags);
> + list_del_init(&vmdirq->node);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> +
> +}
> +
> +static const struct irq_domain_ops vmd_domain_ops = {
> + .alloc = vmd_msi_alloc_irqs,
> + .free = vmd_msi_free_irqs,
> + .activate = vmd_msi_activate,
> + .deactivate = vmd_msi_deactivate,
> +};
> +
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> +static struct device *dev_to_vmd_dev(struct device *dev)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct vmd_dev *vmd = vmd_from_bus(pdev->bus);
> + return &vmd->dev->dev;
> +}
> +
> +static void *vmd_alloc(struct device *dev, size_t size, dma_addr_t *addr,
> + gfp_t flag, struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->alloc(vdev, size, addr, flag, attrs);
> +}
> +
> +static void vmd_free(struct device *dev, size_t size, void *vaddr,
> + dma_addr_t addr, struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->free(vdev, size, vaddr, addr, attrs);
> +}
> +
> +static int vmd_mmap(struct device *dev, struct vm_area_struct *vma,
> + void *cpu_addr, dma_addr_t addr,
> + size_t size, struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->mmap(vdev, vma, cpu_addr, addr, size,
> + attrs);
> +}
> +
> +static int vmd_get_sgtable(struct device *dev, struct sg_table *sgt,
> + void *cpu_addr, dma_addr_t addr,
> + size_t size, struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->get_sgtable(vdev, sgt, cpu_addr, addr,
> + size, attrs);
> +}
> +
> +static dma_addr_t vmd_map_page(struct device *dev, struct page *page,
> + unsigned long offset, size_t size,
> + enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->map_page(vdev, page, offset, size, dir,
> + attrs);
> +}
> +
> +static void vmd_unmap_page(struct device *dev, dma_addr_t addr, size_t size,
> + enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->unmap_page(vdev, addr, size, dir, attrs);
> +}
> +
> +static int vmd_map_sg(struct device *dev, struct scatterlist *sg, int nents,
> + enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->map_sg(dev, sg, nents, dir, attrs);
> +}
> +
> +static void vmd_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
> + enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->unmap_sg(vdev, sg, nents, dir, attrs);
> +}
> +
> +static void vmd_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
> + size_t size, enum dma_data_direction dir)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->sync_single_for_cpu(vdev, addr, size, dir);
> +}
> +
> +static void vmd_sync_single_for_device(struct device *dev, dma_addr_t addr,
> + size_t size, enum dma_data_direction dir)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->sync_single_for_device(vdev, addr, size, dir);
> +}
> +
> +static void vmd_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
> + int nents, enum dma_data_direction dir)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->sync_sg_for_cpu(vdev, sg, nents, dir);
> +}
> +
> +static void vmd_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
> + int nents, enum dma_data_direction dir)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + vdev->archdata.dma_ops->sync_sg_for_device(dev, sg, nents, dir);
> +}
> +
> +static int vmd_mapping_error(struct device *dev, dma_addr_t addr)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->mapping_error(vdev, addr);
> +}
> +
> +static int vmd_dma_supported(struct device *dev, u64 mask)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->dma_supported(vdev, mask);
> +}
> +
> +#ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK
> +u64 vmd_get_required_mask(struct device *dev)
> +{
> + struct device *vdev = dev_to_vmd_dev(dev);
> + return vdev->archdata.dma_ops->get_required_mask(vdev);
> +}
> +#endif
> +#endif
> +
> +static void vmd_teardown_dma_ops(struct vmd_dev *vmd)
> +{
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> + if (vmd->dev->dev.archdata.dma_ops)
> + vmd_del_dma_device(vmd);
> +#endif
> +}
> +
> +static void vmd_setup_dma_ops(struct vmd_dev *vmd)
> +{
> +#ifdef CONFIG_X86_DEV_DMA_OPS
> + struct dma_map_ops *source = vmd->dev->dev.archdata.dma_ops;
> + struct dma_map_ops *dest = &vmd->dma_ops;
> +
> + if (!source)
> + return;
> + if (source->alloc)
> + dest->alloc = vmd_alloc;
> + if (source->free)
> + dest->free = vmd_free;
> + if (source->mmap)
> + dest->mmap = vmd_mmap;
> + if (source->get_sgtable)
> + dest->get_sgtable = vmd_get_sgtable;
> + if (source->map_page)
> + dest->map_page = vmd_map_page;
> + if (source->unmap_page)
> + dest->unmap_page = vmd_unmap_page;
> + if (source->map_sg)
> + dest->map_sg = vmd_map_sg;
> + if (source->unmap_sg)
> + dest->unmap_sg = vmd_unmap_sg;
> + if (source->sync_single_for_cpu)
> + dest->sync_single_for_cpu = vmd_sync_single_for_cpu;
> + if (source->sync_single_for_device)
> + dest->sync_single_for_device = vmd_sync_single_for_device;
> + if (source->sync_sg_for_cpu)
> + dest->sync_sg_for_cpu = vmd_sync_sg_for_cpu;
> + if (source->sync_sg_for_device)
> + dest->sync_sg_for_device = vmd_sync_sg_for_device;
> + if (source->mapping_error)
> + dest->mapping_error = vmd_mapping_error;
> + if (source->dma_supported)
> + dest->dma_supported = vmd_dma_supported;
> +#ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK
> + if (source->get_required_mask)
> + dest->get_required_mask = vmd_get_required_mask;
> +#endif
> + vmd_add_dma_device(vmd);
> +#endif
> +}
> +
> +/*
> + * CPU may deadlock if config space is not serialized on some versions of this
> + * hardware, so all config space access is done under a spinlock.
> + */
> +static int vmd_pci_read(struct pci_bus *bus, unsigned int devfn, int reg,
> + int len, u32 *value)
> +{
> + int ret = 0;
> + unsigned long flags;
> + struct vmd_dev *vmd = vmd_from_bus(bus);
> + char __iomem *addr = vmd->cfgbar + (bus->number << 20) +
> + (devfn << 12) + reg;
> +
> + spin_lock_irqsave(&vmd->cfg_lock, flags);
> + switch (len) {
> + case 1:
> + *value = readb(addr);
> + break;
> + case 2:
> + *value = readw(addr);
> + break;
> + case 4:
> + *value = readl(addr);
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> + spin_unlock_irqrestore(&vmd->cfg_lock, flags);
> + return ret;
> +}
> +
> +/*
> + * VMD h/w converts posted config writes to non-posted. The read-back in this
> + * function forces the completion so it returns only after the config space was
> + * written, as expected.
> + */
> +static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
> + int len, u32 value)
> +{
> + int ret = 0;
> + unsigned long flags;
> + struct vmd_dev *vmd = vmd_from_bus(bus);
> + char __iomem *addr = vmd->cfgbar + (bus->number << 20) +
> + (devfn << 12) + reg;
> +
> + spin_lock_irqsave(&vmd->cfg_lock, flags);
> + switch (len) {
> + case 1:
> + writeb(value, addr);
> + readb(addr);
> + break;
> + case 2:
> + writew(value, addr);
> + readw(addr);
> + break;
> + case 4:
> + writel(value, addr);
> + readl(addr);
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> + spin_unlock_irqrestore(&vmd->cfg_lock, flags);
> + return ret;
> +}
> +
> +static struct pci_ops vmd_ops = {
> + .read = vmd_pci_read,
> + .write = vmd_pci_write,
> +};
> +
> +static int vmd_find_free_domain(void)
> +{
> + int domain = -1;
> + struct pci_bus *bus = NULL;
> +
> + while ((bus = pci_find_next_bus(bus)) != NULL)
> + domain = max_t(int, domain, pci_domain_nr(bus));
> + if (domain < 0)
> + return -ENODEV;
> + return domain + 1;
> +}
The PCI core should own domain number allocation. We have a little
bit of generic domain support, e.g., pci_get_new_domain_nr(). On x86,
I think that is compiled-in, but currently not used -- currently x86
only uses _SEG from ACPI. How would you handle collisions between a
domain number assigned here (or via pci_get_new_domain_nr()) and a
hot-added host bridge where _SEG uses the same domain?
> +
> +static int vmd_enable_domain(struct vmd_dev *vmd)
> +{
> + static const u8 vmd_membars[] = {2, 4};
> + static const u64 vmd_membar_offsets[] = {0, 0x2000};
> + int i = 0;
> + LIST_HEAD(resources);
> + struct pci_sysdata *sd = &vmd->sysdata;
> + struct resource_entry *entry;
> +
> + sd->domain = vmd_find_free_domain();
> + if (sd->domain < 0)
> + return sd->domain;
> + sd->node = pcibus_to_node(vmd->dev->bus);
> +
> + pci_add_resource(&resources, NULL);
> + pci_add_resource(&resources, NULL);
> + pci_add_resource(&resources, NULL);
I don't really like this style of "use pci_add_resource(..., NULL) to
preallocate resource structures, then fill them in later" because
a) Nobody else does it that way,
b) We have (transitory) empty resources in the "resources" list, and
c) If there's a failure, e.g., if the kzalloc() in
resource_list_create_entry() fails, pci_add_resource() doesn't
return an error, and we'll oops with a NULL pointer dereference
below.
I'd prefer to just alloc your own resource here, initialize it, then
add it.
> + resource_list_for_each_entry(entry, &resources) {
> + struct resource *source, *resource = entry->res;
> +
> + if (!i) {
> + resource->start = 0;
> + resource->end = (resource_size(
> + &vmd->dev->resource[0]) >> 20) - 1;
> + resource->flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED;
I thought BAR0 was CFGBAR. I missed the connection to a bus number
aperture.
> + } else {
> + source = &vmd->dev->resource[vmd_membars[i - 1]];
> + resource->start = source->start +
> + vmd_membar_offsets[i - 1];
> + resource->end = source->end;
> + resource->flags = source->flags & ~IORESOURCE_SIZEALIGN;
> + resource->parent = source;
> + if (!upper_32_bits(resource->end))
> + resource->flags &= ~IORESOURCE_MEM_64;
> + }
> + i++;
> + }
> +
> + vmd->irq_domain = arch_create_vmd_msi_irq_domain(vmd->dev, &vmd_domain_ops);
> + if (!vmd->irq_domain)
> + return -ENODEV;
This failure path leaks resource_entry structures, doesn't it?
> +
> + vmd->bus = pci_create_root_bus(NULL, 0, &vmd_ops, sd, &resources);
> + if (!vmd->bus) {
> + pci_free_resource_list(&resources);
> + return -ENODEV;
> + }
> + dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
> + vmd_setup_dma_ops(vmd);
> + pci_scan_child_bus(vmd->bus);
> + pci_bus_size_bridges(vmd->bus);
> + pci_bus_assign_resources(vmd->bus);
> + pci_bus_add_devices(vmd->bus);
> +
> + WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj, "domain"),
> + "Can't create symlink to domain\n");
> + return 0;
> +}
> +
> +static void vmd_flow_handler(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct vmd_irq_list *irqs = irq_desc_get_handler_data(desc);
> + struct vmd_irq *vmdirq;
> +
> + chained_irq_enter(chip, desc);
> + spin_lock(&irqs->irq_lock);
> + list_for_each_entry(vmdirq, &irqs->irq_list, node)
> + generic_handle_irq(vmdirq->virq);
> + spin_unlock(&irqs->irq_lock);
> + chained_irq_exit(chip, desc);
> +}
> +
> +static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
> +{
> + struct vmd_dev *vmd;
> + int i, err;
> +
> + vmd = devm_kzalloc(&dev->dev, sizeof(*vmd), GFP_KERNEL);
> + if (!vmd)
> + return -ENOMEM;
> +
> + err = pcim_enable_device(dev);
> + if (err < 0)
> + return err;
> +
> + vmd->cfgbar = pcim_iomap(dev, 0, 0);
> + if (!vmd->cfgbar)
> + return -ENOMEM;
> +
> + pci_set_master(dev);
> + if (dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(64)) &&
> + dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32)))
> + return -ENODEV;
> +
> + vmd->dev = dev;
> + vmd->msix_count = pci_msix_vec_count(dev);
> + if (!vmd->msix_count)
> + return -ENODEV;
> +
> + vmd->irqs = devm_kcalloc(&dev->dev, vmd->msix_count, sizeof(*vmd->irqs),
> + GFP_KERNEL);
> + if (!vmd->irqs)
> + return -ENOMEM;
> +
> + vmd->msix_entries = devm_kcalloc(&dev->dev, vmd->msix_count,
> + sizeof(*vmd->msix_entries), GFP_KERNEL);
> + if(!vmd->msix_entries)
> + return -ENOMEM;
> + for (i = 0; i < vmd->msix_count; i++)
> + vmd->msix_entries[i].entry = i;
> +
> + vmd->msix_count = pci_enable_msix_range(vmd->dev, vmd->msix_entries, 1,
> + vmd->msix_count);
> + if (vmd->msix_count < 0)
> + return vmd->msix_count;
> +
> + for (i = 0; i < vmd->msix_count; i++) {
> + INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
> + spin_lock_init(&vmd->irqs[i].irq_lock);
> + vmd->irqs[i].vmd_vector = vmd->msix_entries[i].vector;
> + vmd->irqs[i].index = i;
> +
> + irq_set_chained_handler_and_data(vmd->msix_entries[i].vector,
> + vmd_flow_handler, &vmd->irqs[i]);
> + }
> + spin_lock_init(&vmd->cfg_lock);
> + err = vmd_enable_domain(vmd);
> + if (err)
> + return err;
> +
> + pci_set_drvdata(dev, vmd);
> + return 0;
> +}
> +
> +static void vmd_remove(struct pci_dev *dev)
> +{
> + struct pci_bus *bus;
> + struct pci_dev *child, *tmp;
> + struct vmd_dev *vmd = pci_get_drvdata(dev);
> +
> + if (!vmd)
> + return;
How is it possible to get here with "vmd == NULL"? If it's
impossible, remove the test.
> + sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
> + pci_set_drvdata(dev, NULL);
> + bus = vmd->bus;
> + list_for_each_entry_safe(child, tmp, &bus->devices, bus_list)
> + pci_stop_and_remove_bus_device(child);
> + pci_remove_bus(bus);
> + vmd_teardown_dma_ops(vmd);
> +}
> +
> +static const struct pci_device_id vmd_ids[] = {
> + {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x201d),},
> + {0,}
> +};
> +MODULE_DEVICE_TABLE(pci, vmd_ids);
> +
> +struct pci_driver vmd_drv = {
> + .name = "vmd",
> + .id_table = vmd_ids,
> + .probe = vmd_probe,
> + .remove = vmd_remove,
> +};
> +
> +static int __init vmd_init(void)
> +{
> + return pci_register_driver(&vmd_drv);
> +}
> +module_init(vmd_init);
module_pci_driver(vmd_drv)?
> +
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL v2");
> +MODULE_VERSION("0.1");
> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
> index e28169d..e566a6b 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -1062,3 +1062,4 @@ int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(irq_chip_compose_msi_msg);
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index dc9d27c..8303ccb 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -910,6 +910,7 @@ struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
>
> return NULL;
> }
> +EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
>
> /**
> * irq_domain_set_hwirq_and_chip - Set hwirq and irqchip of @virq at @domain
> @@ -934,6 +935,7 @@ int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(irq_domain_set_hwirq_and_chip);
>
> /**
> * irq_domain_set_info - Set the complete data for a @virq in @domain
> @@ -1240,6 +1242,7 @@ struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
>
> return (irq_data && irq_data->domain == domain) ? irq_data : NULL;
> }
> +EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
>
> /**
> * irq_domain_set_info - Set the complete data for a @virq in @domain
> --
> 1.7.10.4
>
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