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Date: Thu, 8 Mar 2012 18:06:07 -0700
From: Bjorn Helgaas <bhelgaas@...gle.com>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Jesse Barnes <jbarnes@...tuousgeek.org>, x86 <x86@...nel.org>,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
David Woodhouse <dwmw2@...radead.org>,
Vinod Koul <vinod.koul@...el.com>,
Dan Williams <dan.j.williams@...el.com>,
iommu@...ts.linux-foundation.org
Subject: Re: [PATCH 07/23] pci, dmar: Update dmar units devices list during hotplug
On Tue, Mar 6, 2012 at 12:13 AM, Yinghai Lu <yinghai@...nel.org> wrote:
> When do pci remove/rescan on system that have more iommus, got
>
> [ 894.089745] Set context mapping for c4:00.0
> [ 894.110890] mpt2sas3: Allocated physical memory: size(4293 kB)
> [ 894.112556] mpt2sas3: Current Controller Queue Depth(1883), Max Controller Queue Depth(2144)
> [ 894.127278] mpt2sas3: Scatter Gather Elements per IO(128)
> [ 894.361295] DRHD: handling fault status reg 2
> [ 894.364053] DMAR:[DMA Read] Request device [c4:00.0] fault addr fffbe000
> [ 894.364056] DMAR:[fault reason 02] Present bit in context entry is cl
>
> it turns out when remove/rescan, pci dev will be freed and will get another new dev.
> but drhd units still keep old one... so dmar_find_matched_drhd_unit will
> return wrong drhd and iommu for the device that is not on first iommu.
>
> So need to update devices in drhd_units during pci remove/rescan.
>
> Could save domain/bus/device/function aside in the list and according that info
> restore new dev to drhd_units later.
> Then dmar_find_matched_drdh_unit and device_to_iommu could return right drhd and iommu.
>
> Add remove_dev_from_drhd/restore_dev_to_drhd functions to do the real work.
> call them in device ADD_DEVICE and UNBOUND_DRIVER
>
> Need to do the samething to atsr. (expose dmar_atsr_units and add atsru->segment)
>
> After patch, will right iommu for the new dev and will not get DMAR error any more.
>
> -v2: add pci_dev_put/pci_dev_get to make refcount consistent.
>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Cc: David Woodhouse <dwmw2@...radead.org>
> Cc: Vinod Koul <vinod.koul@...el.com>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: iommu@...ts.linux-foundation.org
> ---
> drivers/iommu/intel-iommu.c | 187 ++++++++++++++++++++++++++++++++++++++++---
> include/linux/dmar.h | 4 +
> 2 files changed, 181 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index c9c6053..39ef2ce 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -665,6 +665,159 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
> return NULL;
> }
>
> +#ifdef CONFIG_HOTPLUG
> +struct dev_dmaru {
> + struct list_head list;
> + void *dmaru;
> + int index;
> + int segment;
> + unsigned char bus;
> + unsigned int devfn;
> +};
> +
> +static int
> +save_dev_dmaru(int segment, unsigned char bus, unsigned int devfn,
> + void *dmaru, int index, struct list_head *lh)
Follow the indentation style used elsewhere in the file: as much of
the declaration on one line as will fit (here and below).
I think the callers would read more naturally if you passed in the
struct pci_dev * to save_dev_dmaru() and extracted the
segment/bus/devfn here rather than in the callers.
> +{
> + struct dev_dmaru *m;
> +
> + m = kzalloc(sizeof(*m), GFP_KERNEL);
> + if (!m)
> + return -ENOMEM;
> +
> + m->segment = segment;
> + m->bus = bus;
> + m->devfn = devfn;
> + m->dmaru = dmaru;
> + m->index = index;
> +
> + list_add(&m->list, lh);
> +
> + return 0;
> +}
> +
> +static void
> +*get_dev_dmaru(int segment, unsigned char bus, unsigned int devfn,
> + int *index, struct list_head *lh)
> +{
> + struct dev_dmaru *m;
> + void *dmaru = NULL;
> +
> + list_for_each_entry(m, lh, list) {
> + if (m->segment == segment &&
> + m->bus == bus && m->devfn == devfn) {
> + *index = m->index;
> + dmaru = m->dmaru;
> + list_del(&m->list);
> + kfree(m);
> + break;
> + }
> + }
> +
> + return dmaru;
> +}
> +
> +static LIST_HEAD(saved_dev_drhd_list);
> +
> +static void remove_dev_from_drhd(struct pci_dev *dev)
> +{
> + struct dmar_drhd_unit *drhd = NULL;
> + int segment = pci_domain_nr(dev->bus);
> + int i;
> +
> + for_each_drhd_unit(drhd) {
> + if (drhd->ignored)
> + continue;
> + if (segment != drhd->segment)
> + continue;
> +
> + for (i = 0; i < drhd->devices_cnt; i++) {
> + if (drhd->devices[i] == dev) {
> + /* save it at first if it is in drhd */
> + save_dev_dmaru(segment, dev->bus->number,
> + dev->devfn, drhd, i,
> + &saved_dev_drhd_list);
> + /* always remove it */
> + pci_dev_put(dev);
> + drhd->devices[i] = NULL;
> + return;
> + }
> + }
> + }
> +}
> +
> +static void restore_dev_to_drhd(struct pci_dev *dev)
> +{
> + struct dmar_drhd_unit *drhd = NULL;
> + int i;
> +
> + /* find the stored drhd */
> + drhd = get_dev_dmaru(pci_domain_nr(dev->bus), dev->bus->number,
> + dev->devfn, &i, &saved_dev_drhd_list);
> + /* restore that into drhd */
> + if (drhd)
> + drhd->devices[i] = pci_dev_get(dev);
> +}
> +#else
> +static void remove_dev_from_drhd(struct pci_dev *dev)
> +{
> +}
> +
> +static void restore_dev_to_drhd(struct pci_dev *dev)
> +{
> +}
> +#endif
> +
> +#if defined(CONFIG_DMAR) && defined(CONFIG_HOTPLUG)
> +static LIST_HEAD(saved_dev_atsr_list);
> +
> +static void remove_dev_from_atsr(struct pci_dev *dev)
> +{
> + struct dmar_atsr_unit *atsr = NULL;
> + int segment = pci_domain_nr(dev->bus);
> + int i;
> +
> + for_each_atsr_unit(atsr) {
> + if (segment != atsr->segment)
> + continue;
> +
> + for (i = 0; i < atsr->devices_cnt; i++) {
> + if (atsr->devices[i] == dev) {
> + /* save it at first if it is in drhd */
> + save_dev_dmaru(segment, dev->bus->number,
> + dev->devfn, atsr, i,
> + &saved_dev_atsr_list);
> + /* always remove it */
> + pci_dev_put(dev);
> + atsr->devices[i] = NULL;
> + return;
> + }
> + }
> + }
> +}
> +
> +static void restore_dev_to_atsr(struct pci_dev *dev)
> +{
> + struct dmar_atsr_unit *atsr = NULL;
> + int i;
> +
> + /* find the stored atsr */
> + atsr = get_dev_dmaru(pci_domain_nr(dev->bus), dev->bus->number,
> + dev->devfn, &i, &saved_dev_atsr_list);
> + /* restore that into atsr */
> + if (atsr)
> + atsr->devices[i] = pci_dev_get(dev);
> +}
> +#else
> +static void remove_dev_from_atsr(struct pci_dev *dev)
> +{
> +}
> +
> +static void restore_dev_to_atsr(struct pci_dev *dev)
> +{
> +}
> +#endif
> +
> static void domain_flush_cache(struct dmar_domain *domain,
> void *addr, int size)
> {
> @@ -3474,6 +3627,7 @@ int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)
>
> atsru->hdr = hdr;
> atsru->include_all = atsr->flags & 0x1;
> + atsru->segment = atsr->segment;
>
> list_add(&atsru->list, &dmar_atsr_units);
>
> @@ -3505,16 +3659,13 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev)
> {
> int i;
> struct pci_bus *bus;
> - struct acpi_dmar_atsr *atsr;
> struct dmar_atsr_unit *atsru;
>
> dev = pci_physfn(dev);
>
> - list_for_each_entry(atsru, &dmar_atsr_units, list) {
> - atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
> - if (atsr->segment == pci_domain_nr(dev->bus))
> + list_for_each_entry(atsru, &dmar_atsr_units, list)
> + if (atsru->segment == pci_domain_nr(dev->bus))
> goto found;
> - }
>
> return 0;
>
> @@ -3574,20 +3725,36 @@ static int device_notifier(struct notifier_block *nb,
> struct pci_dev *pdev = to_pci_dev(dev);
> struct dmar_domain *domain;
>
> - if (iommu_no_mapping(dev))
> + if (unlikely(dev->bus != &pci_bus_type))
> return 0;
>
> - domain = find_domain(pdev);
> - if (!domain)
> - return 0;
> + switch (action) {
> + case BUS_NOTIFY_UNBOUND_DRIVER:
> + if (iommu_no_mapping(dev))
> + goto out;
> +
> + if (iommu_pass_through)
> + goto out;
> +
> + domain = find_domain(pdev);
> + if (!domain)
> + goto out;
>
> - if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through) {
> domain_remove_one_dev_info(domain, pdev);
>
> if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
> !(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) &&
> list_empty(&domain->devices))
> domain_exit(domain);
> +out:
> + remove_dev_from_drhd(pdev);
> + remove_dev_from_atsr(pdev);
> +
> + break;
> + case BUS_NOTIFY_ADD_DEVICE:
> + restore_dev_to_drhd(pdev);
> + restore_dev_to_atsr(pdev);
> + break;
> }
>
> return 0;
> diff --git a/include/linux/dmar.h b/include/linux/dmar.h
> index 731a609..57e1375 100644
> --- a/include/linux/dmar.h
> +++ b/include/linux/dmar.h
> @@ -236,9 +236,13 @@ struct dmar_atsr_unit {
> struct acpi_dmar_header *hdr; /* ACPI header */
> struct pci_dev **devices; /* target devices */
> int devices_cnt; /* target device count */
> + u16 segment; /* PCI domain */
> u8 include_all:1; /* include all ports */
> };
>
> +#define for_each_atsr_unit(atsr) \
> + list_for_each_entry(atsr, &dmar_atsr_units, list)
> +
> int dmar_parse_rmrr_atsr_dev(void);
> extern int dmar_parse_one_rmrr(struct acpi_dmar_header *header);
> extern int dmar_parse_one_atsr(struct acpi_dmar_header *header);
> --
> 1.7.7
>
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