Introduce the basic concept of 2 level event channels for kernel delivery,
which is just a simple matter of a few test_and_set_bit calls on a mapped
shared info page.
This can be used for routing MSI of passthrough devices to PIRQ event
channels in a Xen guest, and we can build on it for delivering IPIs and
timers directly from the kernel too.
v1: Use kvm_map_gfn() although I didn't quite see how it works.
v2: Avoid kvm_map_gfn() and implement a safe mapping with invalidation
support for myself.
v3: Reinvent gfn_to_pfn_cache with sane invalidation semantics, for my
use case as well as nesting.
v4: Rework dirty handling, as it became apparently that we need an active
vCPU context to mark pages dirty so it can't be done from the MMU
notifier duing the invalidation; it has to happen on unmap.
v5: Fix sparse warnings reported by kernel test robot <lkp@xxxxxxxxx>.
Fix revalidation when memslots change but the resulting HVA stays
the same. We can use the same kernel mapping in that case, if the
HVA → PFN translation was valid before. So that probably means we
shouldn't unmap the "old_hva". Augment the test case to exercise
that one too.
Include the fix for the dirty ring vs. Xen shinfo oops reported
by butt3rflyh4ck <butterflyhuangxx@xxxxxxxxx>.
As in the previous two rounds, the last patch (this time patch 12) is
included as illustration of how we *might* use this for fixing the UAF
bugs in nesting, but isn't intended to be applied as-is. Patches 1-11 are.
David Woodhouse (12):
KVM: Introduce CONFIG_HAVE_KVM_DIRTY_RING
KVM: Add Makefile.kvm for common files, use it for x86
KVM: s390: Use Makefile.kvm for common files
KVM: mips: Use Makefile.kvm for common files
KVM: RISC-V: Use Makefile.kvm for common files
KVM: powerpc: Use Makefile.kvm for common files
KVM: arm64: Use Makefile.kvm for common files
KVM: Reinstate gfn_to_pfn_cache with invalidation support
KVM: x86/xen: Maintain valid mapping of Xen shared_info page
KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery
KVM: x86: Fix wall clock writes in Xen shared_info not to mark page dirty
KVM: x86: First attempt at converting nested virtual APIC page to gpc
Documentation/virt/kvm/api.rst | 33 ++
arch/arm64/kvm/Makefile | 6 +-
arch/mips/kvm/Makefile | 3 +-
arch/powerpc/kvm/Makefile | 6 +-
arch/riscv/kvm/Makefile | 6 +-
arch/s390/kvm/Makefile | 6 +-
arch/x86/include/asm/kvm_host.h | 4 +-
arch/x86/kvm/Kconfig | 2 +
arch/x86/kvm/Makefile | 7 +-
arch/x86/kvm/irq_comm.c | 12 +
arch/x86/kvm/vmx/nested.c | 50 ++-
arch/x86/kvm/vmx/vmx.c | 12 +-
arch/x86/kvm/vmx/vmx.h | 2 +-
arch/x86/kvm/x86.c | 15 +-
arch/x86/kvm/x86.h | 1 -
arch/x86/kvm/xen.c | 341 +++++++++++++++++++--
arch/x86/kvm/xen.h | 9 +
include/linux/kvm_dirty_ring.h | 8 +-
include/linux/kvm_host.h | 110 +++++++
include/linux/kvm_types.h | 18 ++
include/uapi/linux/kvm.h | 11 +
.../testing/selftests/kvm/x86_64/xen_shinfo_test.c | 184 ++++++++++-
virt/kvm/Kconfig | 6 +
virt/kvm/Makefile.kvm | 14 +
virt/kvm/dirty_ring.c | 2 +-
virt/kvm/kvm_main.c | 16 +-
virt/kvm/kvm_mm.h | 44 +++
virt/kvm/mmu_lock.h | 23 --
virt/kvm/pfncache.c | 323 +++++++++++++++++++
29 files changed, 1173 insertions(+), 101 deletions(-)
