Avi Kivity wrote:
> Han, Weidong wrote:
>> Don't need to map mmio pages for iommu. When find mmio pages in
>> kvm_iommu_map_pages(), don't map them, and shouldn't return error
>> due to it's not an error. If return error (such as -EINVAL), device
>> assigment will fail.
>>
>>
>
>
> I don't understand. Why don't we need to map mmio pages? We
> certainly don't want them emulated.
mmio pages need not to be mapped in VT-d page table, which only
translate DMA addresses. Amit's userspace patch register memslot for
mmios of assigned devices, it doesn't emulate them.
>
>> @@ -36,14 +36,13 @@ int kvm_iommu_map_pages(struct kvm *kvm, {
>> gfn_t gfn = base_gfn;
>> pfn_t pfn;
>> - int i, r;
>> + int i, r = 0;
>> struct dmar_domain *domain = kvm->arch.intel_iommu_domain;
>>
>> /* check if iommu exists and in use */
>> if (!domain)
>> return 0;
>>
>> - r = -EINVAL;
>> for (i = 0; i < npages; i++) {
>> /* check if already mapped */
>> pfn = (pfn_t)intel_iommu_iova_to_pfn(domain,
>> @@ -60,13 +59,14 @@ int kvm_iommu_map_pages(struct kvm *kvm,
>> DMA_PTE_READ |
DMA_PTE_WRITE);
>> if (r) {
>> - printk(KERN_DEBUG "kvm_iommu_map_pages:"
>> + printk(KERN_ERR "kvm_iommu_map_pages:"
>> "iommu failed to map pfn=%lx\n",
>> pfn);
>> goto unmap_pages;
>> }
>> } else {
>> - printk(KERN_DEBUG "kvm_iommu_map_page:"
>> - "invalid pfn=%lx\n", pfn);
>> + printk(KERN_DEBUG "kvm_iommu_map_pages:"
>> + "invalid pfn=%lx, iommu needn't map "
>> + "MMIO pages!\n", pfn);
>> goto unmap_pages;
>> }
>
> If a slot has a mix of mmio and non-mmio pages, you will unmap the
> non-mmio pages, yet return no error.
>
I didn't consider this mix case. In this mix case, we don't goto
unmap_pages, actually we should remove else {} block. That maps non-mmio
pages while don't map mmio pages. I will resend the patch.
Randy (Weidong)
> --
> error compiling committee.c: too many arguments to function
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