Is there any feedback on these patches? CVE-2021-22543 was fixed by disallowing mapping of non-refcounted memory. These patches add proper support for mapping that type of memory. -David On Wed, Aug 25, 2021 at 11:50 AM David Stevens <stevensd@xxxxxxxxxxxx> wrote: > > From: David Stevens <stevensd@xxxxxxxxxxxx> > > This patch series adds support for mapping non-refcount VM_IO and > VM_PFNMAP memory into the guest. > > Currently, the gfn_to_pfn functions require being able to pin the target > pfn, so they will fail if the pfn returned by follow_pte isn't a > ref-counted page. However, the KVM secondary MMUs do not require that > the pfn be pinned, since they are integrated with the mmu notifier API. > This series adds a new set of gfn_to_pfn_page functions which parallel > the gfn_to_pfn functions but do not pin the pfn. The new functions > return the page from gup if it was present, so callers can use it and > call put_page when done. > > The gfn_to_pfn functions should be depreciated, since as they are unsafe > due to relying on trying to obtain a struct page from a pfn returned by > follow_pte. I added new functions instead of simply adding another > optional parameter to the existing functions to make it easier to track > down users of the deprecated functions. > > This series updates x86 and arm64 secondary MMUs to the new API. > > v2 -> v3: > - rebase on kvm next branch > v1 -> v2: > - Introduce new gfn_to_pfn_page functions instead of modifying the > behavior of existing gfn_to_pfn functions, to make the change less > invasive. > - Drop changes to mmu_audit.c > - Include Nicholas Piggin's patch to avoid corrupting refcount in the > follow_pte case, and use it in depreciated gfn_to_pfn functions. > - Rebase on kvm/next > > David Stevens (4): > KVM: mmu: introduce new gfn_to_pfn_page functions > KVM: x86/mmu: use gfn_to_pfn_page > KVM: arm64/mmu: use gfn_to_pfn_page > KVM: mmu: remove over-aggressive warnings > > arch/arm64/kvm/mmu.c | 26 +++-- > arch/x86/kvm/mmu/mmu.c | 50 +++++---- > arch/x86/kvm/mmu/mmu_internal.h | 3 +- > arch/x86/kvm/mmu/paging_tmpl.h | 23 ++-- > arch/x86/kvm/mmu/tdp_mmu.c | 6 +- > arch/x86/kvm/mmu/tdp_mmu.h | 4 +- > arch/x86/kvm/x86.c | 6 +- > include/linux/kvm_host.h | 17 +++ > virt/kvm/kvm_main.c | 188 +++++++++++++++++++++++--------- > 9 files changed, 220 insertions(+), 103 deletions(-) > > -- > 2.33.0.rc2.250.ged5fa647cd-goog >
