Paolo Bonzini bd2fae8da7 KVM: do not assume PTE is writable after follow_pfn ... In order to convert an HVA to a PFN, KVM usually tries to use the get_user_pages family of functinso. This however is not possible for VM_IO vmas; in that case, KVM instead uses follow_pfn. In doing this however KVM loses the information on whether the PFN is writable. That is usually not a problem because the main use of VM_IO vmas with KVM is for BARs in PCI device assignment, however it is a bug. To fix it, use follow_pte and check pte_write while under the protection of the PTE lock. The information can be used to fail hva_to_pfn_remapped or passed back to the caller via *writable. Usage of follow_pfn was introduced in commit add6a0cd1c ("KVM: MMU: try to fix up page faults before giving up", 2016-07-05); however, even older version have the same issue, all the way back to commit 2e2e3738af ("KVM: Handle vma regions with no backing page", 2008-07-20), as they also did not check whether the PFN was writable. Fixes: 2e2e3738af ("KVM: Handle vma regions with no backing page") Reported-by: David Stevens <stevensd@google.com> Cc: 3pvd@google.com Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2021-02-04 05:27:14 -05:00
..
async_pf.c	mm/gup: remove task_struct pointer for all gup code	2020-08-12 10:58:04 -07:00
async_pf.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504	2019-06-19 17:09:56 +02:00
coalesced_mmio.c	mm, kvm: account kvm_vcpu_mmap to kmemcg	2020-12-19 11:18:37 -08:00
coalesced_mmio.h
dirty_ring.c	KVM: X86: Implement ring-based dirty memory tracking	2020-11-15 09:49:15 -05:00
eventfd.c	kvm/eventfd: Drain events from eventfd in irqfd_wakeup()	2020-11-15 09:49:11 -05:00
irqchip.c	KVM/arm updates for 5.3	2019-07-11 15:14:16 +02:00
Kconfig	entry: Provide infrastructure for work before transitioning to guest mode	2020-07-24 15:03:42 +02:00
kvm_main.c	KVM: do not assume PTE is writable after follow_pfn	2021-02-04 05:27:14 -05:00
vfio.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
vfio.h