![Lai Jiangshan](/assets/img/avatar_default.png)
The RCU/SRCU API have already changed for proving RCU usage. I got the following dmesg when PROVE_RCU=y because we used incorrect API. This patch coverts rcu_deference() to srcu_dereference() or family API. =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- arch/x86/kvm/mmu.c:3020 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by qemu-system-x86/8550: #0: (&kvm->slots_lock){+.+.+.}, at: [<ffffffffa011a6ac>] kvm_set_memory_region+0x29/0x50 [kvm] #1: (&(&kvm->mmu_lock)->rlock){+.+...}, at: [<ffffffffa012262d>] kvm_arch_commit_memory_region+0xa6/0xe2 [kvm] stack backtrace: Pid: 8550, comm: qemu-system-x86 Not tainted 2.6.34-rc4-tip-01028-g939eab1 #27 Call Trace: [<ffffffff8106c59e>] lockdep_rcu_dereference+0xaa/0xb3 [<ffffffffa012f6c1>] kvm_mmu_calculate_mmu_pages+0x44/0x7d [kvm] [<ffffffffa012263e>] kvm_arch_commit_memory_region+0xb7/0xe2 [kvm] [<ffffffffa011a5d7>] __kvm_set_memory_region+0x636/0x6e2 [kvm] [<ffffffffa011a6ba>] kvm_set_memory_region+0x37/0x50 [kvm] [<ffffffffa015e956>] vmx_set_tss_addr+0x46/0x5a [kvm_intel] [<ffffffffa0126592>] kvm_arch_vm_ioctl+0x17a/0xcf8 [kvm] [<ffffffff810a8692>] ? unlock_page+0x27/0x2c [<ffffffff810bf879>] ? __do_fault+0x3a9/0x3e1 [<ffffffffa011b12f>] kvm_vm_ioctl+0x364/0x38d [kvm] [<ffffffff81060cfa>] ? up_read+0x23/0x3d [<ffffffff810f3587>] vfs_ioctl+0x32/0xa6 [<ffffffff810f3b19>] do_vfs_ioctl+0x495/0x4db [<ffffffff810e6b2f>] ? fget_light+0xc2/0x241 [<ffffffff810e416c>] ? do_sys_open+0x104/0x116 [<ffffffff81382d6d>] ? retint_swapgs+0xe/0x13 [<ffffffff810f3ba6>] sys_ioctl+0x47/0x6a [<ffffffff810021db>] system_call_fastpath+0x16/0x1b Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
242 lines
5.5 KiB
C
242 lines
5.5 KiB
C
/*
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* Copyright (c) 2006, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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*
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* Copyright (C) 2006-2008 Intel Corporation
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* Copyright IBM Corporation, 2008
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* Author: Allen M. Kay <allen.m.kay@intel.com>
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* Author: Weidong Han <weidong.han@intel.com>
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* Author: Ben-Ami Yassour <benami@il.ibm.com>
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*/
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#include <linux/list.h>
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#include <linux/kvm_host.h>
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#include <linux/pci.h>
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#include <linux/dmar.h>
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#include <linux/iommu.h>
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#include <linux/intel-iommu.h>
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static int kvm_iommu_unmap_memslots(struct kvm *kvm);
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static void kvm_iommu_put_pages(struct kvm *kvm,
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gfn_t base_gfn, unsigned long npages);
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int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
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{
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gfn_t gfn = slot->base_gfn;
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unsigned long npages = slot->npages;
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pfn_t pfn;
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int i, r = 0;
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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int flags;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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flags = IOMMU_READ | IOMMU_WRITE;
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if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
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flags |= IOMMU_CACHE;
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for (i = 0; i < npages; i++) {
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/* check if already mapped */
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if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn)))
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continue;
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pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
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r = iommu_map_range(domain,
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gfn_to_gpa(gfn),
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pfn_to_hpa(pfn),
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PAGE_SIZE, flags);
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if (r) {
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printk(KERN_ERR "kvm_iommu_map_address:"
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"iommu failed to map pfn=%lx\n", pfn);
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goto unmap_pages;
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}
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gfn++;
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}
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return 0;
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unmap_pages:
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kvm_iommu_put_pages(kvm, slot->base_gfn, i);
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return r;
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}
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static int kvm_iommu_map_memslots(struct kvm *kvm)
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{
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int i, r = 0;
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struct kvm_memslots *slots;
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slots = kvm_memslots(kvm);
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for (i = 0; i < slots->nmemslots; i++) {
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r = kvm_iommu_map_pages(kvm, &slots->memslots[i]);
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if (r)
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break;
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}
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return r;
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}
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int kvm_assign_device(struct kvm *kvm,
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struct kvm_assigned_dev_kernel *assigned_dev)
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{
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struct pci_dev *pdev = NULL;
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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int r, last_flags;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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pdev = assigned_dev->dev;
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if (pdev == NULL)
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return -ENODEV;
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r = iommu_attach_device(domain, &pdev->dev);
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if (r) {
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printk(KERN_ERR "assign device %x:%x:%x.%x failed",
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pci_domain_nr(pdev->bus),
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pdev->bus->number,
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PCI_SLOT(pdev->devfn),
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PCI_FUNC(pdev->devfn));
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return r;
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}
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last_flags = kvm->arch.iommu_flags;
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if (iommu_domain_has_cap(kvm->arch.iommu_domain,
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IOMMU_CAP_CACHE_COHERENCY))
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kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
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/* Check if need to update IOMMU page table for guest memory */
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if ((last_flags ^ kvm->arch.iommu_flags) ==
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KVM_IOMMU_CACHE_COHERENCY) {
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kvm_iommu_unmap_memslots(kvm);
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r = kvm_iommu_map_memslots(kvm);
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if (r)
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goto out_unmap;
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}
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printk(KERN_DEBUG "assign device %x:%x:%x.%x\n",
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assigned_dev->host_segnr,
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assigned_dev->host_busnr,
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PCI_SLOT(assigned_dev->host_devfn),
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PCI_FUNC(assigned_dev->host_devfn));
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return 0;
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out_unmap:
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kvm_iommu_unmap_memslots(kvm);
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return r;
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}
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int kvm_deassign_device(struct kvm *kvm,
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struct kvm_assigned_dev_kernel *assigned_dev)
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{
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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struct pci_dev *pdev = NULL;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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pdev = assigned_dev->dev;
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if (pdev == NULL)
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return -ENODEV;
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iommu_detach_device(domain, &pdev->dev);
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printk(KERN_DEBUG "deassign device %x:%x:%x.%x\n",
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assigned_dev->host_segnr,
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assigned_dev->host_busnr,
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PCI_SLOT(assigned_dev->host_devfn),
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PCI_FUNC(assigned_dev->host_devfn));
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return 0;
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}
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int kvm_iommu_map_guest(struct kvm *kvm)
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{
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int r;
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if (!iommu_found()) {
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printk(KERN_ERR "%s: iommu not found\n", __func__);
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return -ENODEV;
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}
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kvm->arch.iommu_domain = iommu_domain_alloc();
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if (!kvm->arch.iommu_domain)
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return -ENOMEM;
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r = kvm_iommu_map_memslots(kvm);
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if (r)
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goto out_unmap;
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return 0;
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out_unmap:
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kvm_iommu_unmap_memslots(kvm);
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return r;
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}
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static void kvm_iommu_put_pages(struct kvm *kvm,
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gfn_t base_gfn, unsigned long npages)
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{
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gfn_t gfn = base_gfn;
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pfn_t pfn;
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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unsigned long i;
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u64 phys;
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/* check if iommu exists and in use */
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if (!domain)
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return;
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for (i = 0; i < npages; i++) {
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phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
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pfn = phys >> PAGE_SHIFT;
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kvm_release_pfn_clean(pfn);
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gfn++;
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}
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iommu_unmap_range(domain, gfn_to_gpa(base_gfn), PAGE_SIZE * npages);
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}
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static int kvm_iommu_unmap_memslots(struct kvm *kvm)
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{
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int i;
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struct kvm_memslots *slots;
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slots = kvm_memslots(kvm);
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for (i = 0; i < slots->nmemslots; i++) {
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kvm_iommu_put_pages(kvm, slots->memslots[i].base_gfn,
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slots->memslots[i].npages);
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}
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return 0;
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}
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int kvm_iommu_unmap_guest(struct kvm *kvm)
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{
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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kvm_iommu_unmap_memslots(kvm);
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iommu_domain_free(domain);
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return 0;
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}
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