[PATCH v3 0/5] KVM: MMU: 5 level EPT/shadow support

Yu Zhang
2017-08-24T12:50:33Z

Intel's existing processors limit the maximum linear address width to
48 bits, and the maximum physical address width to 46 bits. And the
upcoming processors will extend maximum linear address width to 57 bits
and maximum physical address width can go upto 52 bits in practical.

With linear address width greater than 48, a new paging mode in IA-32e
is introduced - 5 level paging(also known as LA57). And to support VMs
with this feature, KVM MMU code need to be extended.

And to achieve this, this patchset:
1> leverages 2 qemu parameters: +la57 and phys-bits to expose wider linear
address width and physical address width to the VM;
2> extends shadow logic to construct 5 level shadow page for VMs running
in LA57 mode;
3> extends ept logic to construct 5 level ept table for VMs whose maximum
physical width exceeds 48 bits.

Changes in v3:
- Address comments from Paolo Bonzini: do not fall into check_cpuid_limit()
in kvm_cpuid() for em_movbe() and check_fxsr();
- Address comments from Paolo Bonzini: change parameter 'check_limit' of
kvm_cpuid() to bool type;
- Address comments from Paolo Bonzini: set maxphyaddr to 36, for guest cr3
reserved bits check if cpuid.0x80000008 is not available;
- Address comments from Paolo Bonzini: replace the hardcoded value 48 as
va_bits in __linearize();
- Rebase change: add new eptp definition VMX_EPTP_PWL_5, instead of use bit
shifts(in line with previous commit bb97a01).

Changes in v2:
- Address comments from Paolo Bonzini and Jim Mattson: add a new patch to let
kvm_cpuid() return false when cpuid entry is not found;
- Address comments from Paolo Bonzini: fix a typo in check_cr_write() and use
62 as the upper limit when checking reserved bits for a physical address;
- Address comments from Paolo Bonzini: move definition of PT64_ROOT_MAX_LEVEL
into kvm_host.h;
- Address comments from Paolo Bonzini: add checking for shadow_root_level in
mmu_free_roots();
- Address comments from Paolo Bonzini: set root_level & shadow_root_level both
to PT64_ROOT_4LEVEL for shadow ept situation.

Yu Zhang (5):
KVM: x86: Add return value to kvm_cpuid().
KVM: MMU: check guest CR3 reserved bits based on its physical address
width.
KVM: MMU: Rename PT64_ROOT_LEVEL to PT64_ROOT_4LEVEL.
KVM: MMU: Add 5 level EPT & Shadow page table support.
KVM: MMU: Expose the LA57 feature to VM.

arch/x86/include/asm/kvm_emulate.h | 4 +--
arch/x86/include/asm/kvm_host.h | 31 ++++++--------------
arch/x86/include/asm/vmx.h | 2 ++
arch/x86/kvm/cpuid.c | 38 +++++++++++++++++-------
arch/x86/kvm/cpuid.h | 3 +-
arch/x86/kvm/emulate.c | 42 +++++++++++++++++----------
arch/x86/kvm/kvm_cache_regs.h | 2 +-
arch/x86/kvm/mmu.c | 59 ++++++++++++++++++++++++--------------
arch/x86/kvm/mmu.h | 6 +++-
arch/x86/kvm/mmu_audit.c | 4 +--
arch/x86/kvm/svm.c | 8 +++---
arch/x86/kvm/trace.h | 11 ++++---
arch/x86/kvm/vmx.c | 29 ++++++++++++-------
arch/x86/kvm/x86.c | 21 ++++++++------
arch/x86/kvm/x86.h | 44 ++++++++++++++++++++++++++++
15 files changed, 201 insertions(+), 103 deletions(-)

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2.5.0