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authorChristoffer Dall <christoffer.dall@linaro.org>2014-11-27 04:35:03 -0500
committerChristoffer Dall <christoffer.dall@linaro.org>2014-12-13 08:15:27 -0500
commit957db105c99792ae8ef61ffc9ae77d910f6471da (patch)
tree7a752a94484cc703dfdbf62424f0ef496e03fa88 /arch/arm
parentcf5d318865e25f887d49a0c6083bbc6dcd1905b1 (diff)
arm/arm64: KVM: Introduce stage2_unmap_vm
Introduce a new function to unmap user RAM regions in the stage2 page tables. This is needed on reboot (or when the guest turns off the MMU) to ensure we fault in pages again and make the dcache, RAM, and icache coherent. Using unmap_stage2_range for the whole guest physical range does not work, because that unmaps IO regions (such as the GIC) which will not be recreated or in the best case faulted in on a page-by-page basis. Call this function on secondary and subsequent calls to the KVM_ARM_VCPU_INIT ioctl so that a reset VCPU will detect the guest Stage-1 MMU is off when faulting in pages and make the caches coherent. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/include/asm/kvm_mmu.h1
-rw-r--r--arch/arm/kvm/arm.c7
-rw-r--r--arch/arm/kvm/mmu.c65
3 files changed, 73 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index f867060035ec..63e0ecc04901 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -52,6 +52,7 @@ int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
52void free_boot_hyp_pgd(void); 52void free_boot_hyp_pgd(void);
53void free_hyp_pgds(void); 53void free_hyp_pgds(void);
54 54
55void stage2_unmap_vm(struct kvm *kvm);
55int kvm_alloc_stage2_pgd(struct kvm *kvm); 56int kvm_alloc_stage2_pgd(struct kvm *kvm);
56void kvm_free_stage2_pgd(struct kvm *kvm); 57void kvm_free_stage2_pgd(struct kvm *kvm);
57int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, 58int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 4043769583e7..da87c07d8577 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -701,6 +701,13 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
701 if (ret) 701 if (ret)
702 return ret; 702 return ret;
703 703
704 /*
705 * Ensure a rebooted VM will fault in RAM pages and detect if the
706 * guest MMU is turned off and flush the caches as needed.
707 */
708 if (vcpu->arch.has_run_once)
709 stage2_unmap_vm(vcpu->kvm);
710
704 vcpu_reset_hcr(vcpu); 711 vcpu_reset_hcr(vcpu);
705 712
706 /* 713 /*
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index f2a9874ff5cb..3756dd3e85c2 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -611,6 +611,71 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
611 unmap_range(kvm, kvm->arch.pgd, start, size); 611 unmap_range(kvm, kvm->arch.pgd, start, size);
612} 612}
613 613
614static void stage2_unmap_memslot(struct kvm *kvm,
615 struct kvm_memory_slot *memslot)
616{
617 hva_t hva = memslot->userspace_addr;
618 phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
619 phys_addr_t size = PAGE_SIZE * memslot->npages;
620 hva_t reg_end = hva + size;
621
622 /*
623 * A memory region could potentially cover multiple VMAs, and any holes
624 * between them, so iterate over all of them to find out if we should
625 * unmap any of them.
626 *
627 * +--------------------------------------------+
628 * +---------------+----------------+ +----------------+
629 * | : VMA 1 | VMA 2 | | VMA 3 : |
630 * +---------------+----------------+ +----------------+
631 * | memory region |
632 * +--------------------------------------------+
633 */
634 do {
635 struct vm_area_struct *vma = find_vma(current->mm, hva);
636 hva_t vm_start, vm_end;
637
638 if (!vma || vma->vm_start >= reg_end)
639 break;
640
641 /*
642 * Take the intersection of this VMA with the memory region
643 */
644 vm_start = max(hva, vma->vm_start);
645 vm_end = min(reg_end, vma->vm_end);
646
647 if (!(vma->vm_flags & VM_PFNMAP)) {
648 gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
649 unmap_stage2_range(kvm, gpa, vm_end - vm_start);
650 }
651 hva = vm_end;
652 } while (hva < reg_end);
653}
654
655/**
656 * stage2_unmap_vm - Unmap Stage-2 RAM mappings
657 * @kvm: The struct kvm pointer
658 *
659 * Go through the memregions and unmap any reguler RAM
660 * backing memory already mapped to the VM.
661 */
662void stage2_unmap_vm(struct kvm *kvm)
663{
664 struct kvm_memslots *slots;
665 struct kvm_memory_slot *memslot;
666 int idx;
667
668 idx = srcu_read_lock(&kvm->srcu);
669 spin_lock(&kvm->mmu_lock);
670
671 slots = kvm_memslots(kvm);
672 kvm_for_each_memslot(memslot, slots)
673 stage2_unmap_memslot(kvm, memslot);
674
675 spin_unlock(&kvm->mmu_lock);
676 srcu_read_unlock(&kvm->srcu, idx);
677}
678
614/** 679/**
615 * kvm_free_stage2_pgd - free all stage-2 tables 680 * kvm_free_stage2_pgd - free all stage-2 tables
616 * @kvm: The KVM struct pointer for the VM. 681 * @kvm: The KVM struct pointer for the VM.