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Date: Wed, 8 Jan 2014 13:07:57 +0800
From: Kai Huang <dev.kai.huang@...il.com>
To: Jiang Liu <jiang.liu@...ux.intel.com>
Cc: Joerg Roedel <joro@...tes.org>,
David Woodhouse <dwmw2@...radead.org>,
Yinghai Lu <yinghai@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Dan Williams <dan.j.williams@...el.com>,
Vinod Koul <vinod.koul@...el.com>,
Tony Luck <tony.luck@...el.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
iommu@...ts.linux-foundation.org
Subject: Re: [RFC Patch Part2 V1 14/14] iommu/vt-d: update IOMMU state when
memory hotplug happens
On Tue, Jan 7, 2014 at 5:00 PM, Jiang Liu <jiang.liu@...ux.intel.com> wrote:
> If static identity domain is created, IOMMU driver needs to update
> si_domain page table when memory hotplug event happens. Otherwise
> PCI device DMA operations can't access the hot-added memory regions.
>
> Signed-off-by: Jiang Liu <jiang.liu@...ux.intel.com>
> ---
> drivers/iommu/intel-iommu.c | 52 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 83e3ed4..35a987d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -33,6 +33,7 @@
> #include <linux/dmar.h>
> #include <linux/dma-mapping.h>
> #include <linux/mempool.h>
> +#include <linux/memory.h>
> #include <linux/timer.h>
> #include <linux/iova.h>
> #include <linux/iommu.h>
> @@ -3689,6 +3690,54 @@ static struct notifier_block device_nb = {
> .notifier_call = device_notifier,
> };
>
> +static int intel_iommu_memory_notifier(struct notifier_block *nb,
> + unsigned long val, void *v)
> +{
> + struct memory_notify *mhp = v;
> + unsigned long long start, end;
> + struct iova *iova;
> +
> + switch (val) {
> + case MEM_GOING_ONLINE:
> + start = mhp->start_pfn << PAGE_SHIFT;
> + end = ((mhp->start_pfn + mhp->nr_pages) << PAGE_SHIFT) - 1;
> + if (iommu_domain_identity_map(si_domain, start, end)) {
> + pr_warn("dmar: failed to build identity map for [%llx-%llx]\n",
> + start, end);
> + return NOTIFY_BAD;
> + }
Better to use iommu_prepare_identity_map? For si_domain, if
hw_pass_through is used, there's no page table.
> + break;
> + case MEM_OFFLINE:
> + case MEM_CANCEL_ONLINE:
> + /* TODO: enhance RB-tree and IOVA code to support of splitting iova */
> + iova = find_iova(&si_domain->iovad, mhp->start_pfn);
> + if (iova) {
> + unsigned long start_pfn, last_pfn;
> + struct dmar_drhd_unit *drhd;
> + struct intel_iommu *iommu;
> +
> + start_pfn = mm_to_dma_pfn(iova->pfn_lo);
> + last_pfn = mm_to_dma_pfn(iova->pfn_hi + 1) - 1;
> + dma_pte_clear_range(si_domain, start_pfn, last_pfn);
> + dma_pte_free_pagetable(si_domain, start_pfn, last_pfn);
> + rcu_read_lock();
> + for_each_active_iommu(iommu, drhd)
> + iommu_flush_iotlb_psi(iommu, si_domain->id,
> + start_pfn, last_pfn - start_pfn + 1, 0);
> + rcu_read_unlock();
> + __free_iova(&si_domain->iovad, iova);
> + }
The same as above. Looks we need to consider hw_pass_through for the si_domain.
-Kai
> + break;
> + }
> +
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block intel_iommu_memory_nb = {
> + .notifier_call = intel_iommu_memory_notifier,
> + .priority = 0
> +};
> +
> int __init intel_iommu_init(void)
> {
> int ret = -ENODEV;
> @@ -3761,8 +3810,9 @@ int __init intel_iommu_init(void)
> init_iommu_pm_ops();
>
> bus_set_iommu(&pci_bus_type, &intel_iommu_ops);
> -
> bus_register_notifier(&pci_bus_type, &device_nb);
> + if (si_domain)
> + register_memory_notifier(&intel_iommu_memory_nb);
>
> intel_iommu_enabled = 1;
>
> --
> 1.7.10.4
>
> _______________________________________________
> iommu mailing list
> iommu@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
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