[Intel-gfx] [PATCH v3 00/28] drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups

Sean Christopherson
2023-05-13T00:36:09Z

Fix a variety of found-by-inspection bugs in KVMGT, and overhaul KVM's
page-track APIs to provide a leaner and cleaner interface. The motivation
for this series is to (significantly) reduce the number of KVM APIs that
KVMGT uses, with a long-term goal of making all kvm_host.h headers
KVM-internal.

As always for this series, the KVMGT changes are compile tested only.

Based on "git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/kvm-6.4-1".

v3:
- Collect reviewed/tested tags (I apologize if I missed any, I manually
gathered them this time due to a goof in my workflow). [Yan]
- Drop check on max KVM paging size from KVMGT. [Yan]
- Drop the explicit change on THP pages, and instead validate that the
pfns (not struct page pointers) are contiguous. [Yan]
- Fix buggy intel_gvt_dma_map_guest_page() usage by eliminating a helper
for shadowing 2MiB GTT entries. [Yan]
- Move kvm_arch_flush_shadow_{all,memslot}() to mmu.c instead of exposing
kvm_mmu_zap_all_fast() outside of mmu.c. [Yan]
- Fix an alignment goof in hlist_for_each_entry_srcu() usage. [Yan]
- Wrap full definition of external page track structures with
CONFIG_KVM_EXTERNAL_WRITE_TRACKING. [Yan]

v2:
- https://lore.kernel.org/all/20230311002258.852397-1-seanjc@google.com
- Reuse vgpu_lock to protect gfn hash instead of introducing a new (and
buggy) mutext. [Yan]
- Remove a spurious return from kvm_page_track_init(). [Yan]
- Take @kvm directly in the inner __kvm_page_track_write(). [Yan]
- Delete the gfn sanity check that relies on kvm_is_visible_gfn() instead
of providing a dedicated interface. [Yan]

v1: https://lore.kernel.org/lkml/20221223005739.1295925-1-seanjc@google.com

Sean Christopherson (24):
drm/i915/gvt: Verify pfn is "valid" before dereferencing "struct page"
drm/i915/gvt: Verify hugepages are contiguous in physical address
space
drm/i915/gvt: Put the page reference obtained by KVM's gfn_to_pfn()
drm/i915/gvt: Explicitly check that vGPU is attached before shadowing
drm/i915/gvt: Error out on an attempt to shadowing an unknown GTT
entry type
drm/i915/gvt: Don't rely on KVM's gfn_to_pfn() to query possible 2M
GTT
drm/i915/gvt: Use an "unsigned long" to iterate over memslot gfns
drm/i915/gvt: Drop unused helper intel_vgpu_reset_gtt()
drm/i915/gvt: Protect gfn hash table with vgpu_lock
KVM: x86/mmu: Move kvm_arch_flush_shadow_{all,memslot}() to mmu.c
KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot
change
KVM: x86/mmu: Don't bounce through page-track mechanism for guest PTEs
KVM: drm/i915/gvt: Drop @vcpu from KVM's ->track_write() hook
KVM: x86: Reject memslot MOVE operations if KVMGT is attached
drm/i915/gvt: Don't bother removing write-protection on to-be-deleted
slot
KVM: x86/mmu: Move KVM-only page-track declarations to internal header
KVM: x86/mmu: Use page-track notifiers iff there are external users
KVM: x86/mmu: Drop infrastructure for multiple page-track modes
KVM: x86/mmu: Rename page-track APIs to reflect the new reality
KVM: x86/mmu: Assert that correct locks are held for page
write-tracking
KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled
KVM: x86/mmu: Drop @slot param from exported/external page-track APIs
KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers
drm/i915/gvt: Drop final dependencies on KVM internal details

Yan Zhao (4):
drm/i915/gvt: remove interface intel_gvt_is_valid_gfn
KVM: x86: Add a new page-track hook to handle memslot deletion
drm/i915/gvt: switch from ->track_flush_slot() to
->track_remove_region()
KVM: x86: Remove the unused page-track hook track_flush_slot()

arch/x86/include/asm/kvm_host.h | 16 +-
arch/x86/include/asm/kvm_page_track.h | 73 +++-----
arch/x86/kvm/mmu.h | 2 +
arch/x86/kvm/mmu/mmu.c | 51 +++--
arch/x86/kvm/mmu/page_track.c | 256 +++++++++++++-------------
arch/x86/kvm/mmu/page_track.h | 58 ++++++
arch/x86/kvm/x86.c | 22 +--
drivers/gpu/drm/i915/gvt/gtt.c | 102 ++--------
drivers/gpu/drm/i915/gvt/gtt.h | 1 -
drivers/gpu/drm/i915/gvt/gvt.h | 3 +-
drivers/gpu/drm/i915/gvt/kvmgt.c | 117 +++++-------
drivers/gpu/drm/i915/gvt/page_track.c | 10 +-
12 files changed, 320 insertions(+), 391 deletions(-)
create mode 100644 arch/x86/kvm/mmu/page_track.h

base-commit: b3c98052d46948a8d65d2778c7f306ff38366aac
--
2.40.1.606.ga4b1b128d6-goog