| Message ID | 1410990981-665-7-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Wed, Sep 17, 2014 at 02:56:21PM -0700, Ard Biesheuvel wrote: > There is really no point in faulting in memory regions page by page > if they are not backed by demand paged system RAM but by a linear > passthrough mapping of a host MMIO region. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm/kvm/mmu.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 49 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > index fe53c3a30383..b153ef0c6d9f 100644 > --- a/arch/arm/kvm/mmu.c > +++ b/arch/arm/kvm/mmu.c > @@ -1162,7 +1162,55 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free, > int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, > unsigned long npages) > { > - return 0; > + hva_t hva = slot->userspace_addr; > + phys_addr_t gpa = slot->base_gfn << PAGE_SHIFT; > + phys_addr_t size = slot->npages << PAGE_SHIFT; > + int ret = 0; > + > + /* > + * A memslot could potentially cover multiple VMAs, so iterate > + * over all of them to find out if we can map any of them right now. > + * > + * +--------------------------------------------+ > + * +---+---------+-------------------+--------------+----+ > + * | : VMA 1 | VMA 2 | VMA 3 : | > + * +---+---------+-------------------+--------------+----+ > + * | memslot | > + * +--------------------------------------------+ > + */ > + do { > + struct vm_area_struct *vma = find_vma(current->mm, hva); > + hva_t start, end; > + > + if (!vma || vma->vm_start > hva) { > + ret = -EFAULT; > + break; > + } > + > + start = max(slot->userspace_addr, vma->vm_start); > + end = min((hva_t)(slot->userspace_addr + size), vma->vm_end); > + > + if (vma->vm_flags & VM_PFNMAP) { > + phys_addr_t pa = (vma->vm_pgoff << PAGE_SHIFT) + start - > + vma->vm_start; > + bool writable = vma->vm_flags & VM_WRITE && > + !(slot->flags & KVM_MEM_READONLY); > + > + ret = kvm_phys_addr_ioremap(kvm, gpa, pa, end - start, > + writable); > + if (ret) > + break; > + } > + hva += end - start; > + gpa += end - start; > + } while (hva < slot->userspace_addr + size); > + > + if (ret) { > + spin_lock(&kvm->mmu_lock); > + unmap_stage2_range(kvm, slot->base_gfn << PAGE_SHIFT, size); > + spin_unlock(&kvm->mmu_lock); > + } > + return ret; > } > > void kvm_arch_memslots_updated(struct kvm *kvm) > -- > 1.8.3.2 > Looks really good! But we should handle moving a memslot as well, which also tells me we should probably move this logic to kvm_arch_prepare_memory_region() instead... Thanks, -Christoffer
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index fe53c3a30383..b153ef0c6d9f 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1162,7 +1162,55 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free, int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, unsigned long npages) { - return 0; + hva_t hva = slot->userspace_addr; + phys_addr_t gpa = slot->base_gfn << PAGE_SHIFT; + phys_addr_t size = slot->npages << PAGE_SHIFT; + int ret = 0; + + /* + * A memslot could potentially cover multiple VMAs, so iterate + * over all of them to find out if we can map any of them right now. + * + * +--------------------------------------------+ + * +---+---------+-------------------+--------------+----+ + * | : VMA 1 | VMA 2 | VMA 3 : | + * +---+---------+-------------------+--------------+----+ + * | memslot | + * +--------------------------------------------+ + */ + do { + struct vm_area_struct *vma = find_vma(current->mm, hva); + hva_t start, end; + + if (!vma || vma->vm_start > hva) { + ret = -EFAULT; + break; + } + + start = max(slot->userspace_addr, vma->vm_start); + end = min((hva_t)(slot->userspace_addr + size), vma->vm_end); + + if (vma->vm_flags & VM_PFNMAP) { + phys_addr_t pa = (vma->vm_pgoff << PAGE_SHIFT) + start - + vma->vm_start; + bool writable = vma->vm_flags & VM_WRITE && + !(slot->flags & KVM_MEM_READONLY); + + ret = kvm_phys_addr_ioremap(kvm, gpa, pa, end - start, + writable); + if (ret) + break; + } + hva += end - start; + gpa += end - start; + } while (hva < slot->userspace_addr + size); + + if (ret) { + spin_lock(&kvm->mmu_lock); + unmap_stage2_range(kvm, slot->base_gfn << PAGE_SHIFT, size); + spin_unlock(&kvm->mmu_lock); + } + return ret; } void kvm_arch_memslots_updated(struct kvm *kvm)
There is really no point in faulting in memory regions page by page if they are not backed by demand paged system RAM but by a linear passthrough mapping of a host MMIO region. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/kvm/mmu.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-)