Commit fd6f17ba authored by Keqian Zhu's avatar Keqian Zhu Committed by Marc Zyngier
Browse files

KVM: arm64: Remove the creation time's mapping of MMIO regions 



The MMIO regions may be unmapped for many reasons and can be remapped
by stage2 fault path. Map MMIO regions at creation time becomes a
minor optimization and makes these two mapping path hard to sync.

Remove the mapping code while keep the useful sanity check.

Signed-off-by: default avatarKeqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210507110322.23348-2-zhukeqian1@huawei.com
parent 8124c8a6

arch/arm64/kvm/mmu.c

+3 −35
Original line number Diff line number Diff line
@@ -1346,7 +1346,6 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, 
{

	hva_t hva = mem->userspace_addr;

	hva_t reg_end = hva + mem->memory_size;

	bool writable = !(mem->flags & KVM_MEM_READONLY);

	int ret = 0;



	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
@@ -1363,8 +1362,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, 
	mmap_read_lock(current->mm);

	/*

	 * A memory region could potentially cover multiple VMAs, and any holes

	 * between them, so iterate over all of them to find out if we can map

	 * any of them right now.

	 * between them, so iterate over all of them.

	 *

	 *     +--------------------------------------------+

	 * +---------------+----------------+   +----------------+
@@ -1375,51 +1373,21 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, 
	 */

	do {

		struct vm_area_struct *vma;

		hva_t vm_start, vm_end;



		vma = find_vma_intersection(current->mm, hva, reg_end);

		if (!vma)

			break;



		/*

		 * Take the intersection of this VMA with the memory region

		 */

		vm_start = max(hva, vma->vm_start);

		vm_end = min(reg_end, vma->vm_end);



		if (vma->vm_flags & VM_PFNMAP) {

			gpa_t gpa = mem->guest_phys_addr +

				    (vm_start - mem->userspace_addr);

			phys_addr_t pa;



			pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;

			pa += vm_start - vma->vm_start;



			/* IO region dirty page logging not allowed */

			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {

				ret = -EINVAL;

				goto out;

			}



			ret = kvm_phys_addr_ioremap(kvm, gpa, pa,

						    vm_end - vm_start,

						    writable);

			if (ret)

				break;

			}

		hva = vm_end;

		}

		hva = min(reg_end, vma->vm_end);

	} while (hva < reg_end);



	if (change == KVM_MR_FLAGS_ONLY)

		goto out;



	spin_lock(&kvm->mmu_lock);

	if (ret)

		unmap_stage2_range(&kvm->arch.mmu, mem->guest_phys_addr, mem->memory_size);

	else if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))

		stage2_flush_memslot(kvm, memslot);

	spin_unlock(&kvm->mmu_lock);

out:

	mmap_read_unlock(current->mm);

	return ret;

}