Re: [PATCH 06/11] kvm: Change kvm_iommu_map_pages to map large pages

Marcelo Tosatti
2010-02-07T18:41:33Z

On Sun, Feb 07, 2010 at 02:18:19PM +0200, Avi Kivity wrote:
> On 01/29/2010 12:24 AM, Marcelo Tosatti wrote:
> >On Thu, Jan 28, 2010 at 12:37:57PM +0100, Joerg Roedel wrote:
> >>This patch changes the implementation of of
> >>kvm_iommu_map_pages to map the pages with the host page size
> >>into the io virtual address space.
> >>
> >>Signed-off-by: Joerg Roedel<joerg.roedel@amd.com>
> >>---
> >> virt/kvm/iommu.c | 106 ++++++++++++++++++++++++++++++++++++++++++-----------
> >> 1 files changed, 84 insertions(+), 22 deletions(-)
> >>
> >>diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
> >>index 65a5143..92a434d 100644
> >>--- a/virt/kvm/iommu.c
> >>+++ b/virt/kvm/iommu.c
> >>@@ -32,12 +32,27 @@ static int kvm_iommu_unmap_memslots(struct kvm *kvm);
> >> static void kvm_iommu_put_pages(struct kvm *kvm,
> >> gfn_t base_gfn, unsigned long npages);
> >>
> >>+static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
> >>+ gfn_t gfn, unsigned long size)
> >>+{
> >>+ gfn_t end_gfn;
> >>+ pfn_t pfn;
> >>+
> >>+ pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
> >If gfn_to_pfn_memslot returns pfn of bad_page, you might create a
> >large iommu translation for it?
>
> How could it return a bad_page? The whole thing is called for a valid slot.

Userspace can pass a valid slot with a read-only vma, for example.