[PATCH v5 0/7] KVM: PKS Virtualization support

From: Chenyi Qiang
Date: Wed Aug 11 2021 - 06:07:12 EST

This patch series is based on top of kernel patchset:

To help patches review, one missing info in SDM is that PKSR will be
cleared on Powerup/INIT/RESET, which should be listed in Table 9.1
"IA-32 and Intel 64 Processor States Following Power-up, Reset, or INIT"


Protection Keys for Supervisor Pages(PKS) is a feature that extends the
Protection Keys architecture to support thread-specific permission
restrictions on supervisor pages.

PKS works similar to an existing feature named PKU(protecting user pages).
They both perform an additional check after normal paging permission
checks are done. Access or Writes can be disabled via a MSR update
without TLB flushes when permissions changes. If violating this
addional check, #PF occurs and PFEC.PK bit will be set.

PKS introduces MSR IA32_PKRS to manage supervisor protection key
rights. The MSR contains 16 pairs of ADi and WDi bits. Each pair
advertises on a group of pages with the same key which is set in the
leaf paging-structure entries(bits[62:59]). Currently, IA32_PKRS is not
supported by XSAVES architecture.

This patchset aims to add the virtualization of PKS in KVM. It
implemented PKS CPUID enumeration, vmentry/vmexit configuration, MSR
exposure, nested supported etc. Currently, PKS is not yet supported for
shadow paging.

Detailed information about PKS can be found in the latest Intel 64 and
IA-32 Architectures Software Developer's Manual.



- Make setting of MSR intercept/vmcs control bits not dependent on guest.CR4.PKS.
And set them if PKS is exposed to guest. (Suggested by Sean)
- Add pkrs to standard register caching mechanism to help update
vcpu->arch.pkrs on demand. Add related helper functions. (Suggested by Sean)
- Do the real pkrs update in VMCS field in vmx_vcpu_reset and
vmx_sync_vmcs_host_state(). (Sean)
- Add a new mmu_role cr4_pks instead of smushing PKU and PKS together.
(Sean & Paolo)
- v4: https://lore.kernel.org/lkml/20210205083706.14146-1-chenyi.qiang@xxxxxxxxx/

- Make the MSR intercept and load-controls setting depend on CR4.PKS value
- shadow the guest pkrs and make it usable in PKS emultion
- add the cr4_pke and cr4_pks check in pkr_mask update
- squash PATCH 2 and PATCH 5 to make the dependencies read more clear
- v3: https://lore.kernel.org/lkml/20201105081805.5674-1-chenyi.qiang@xxxxxxxxx/

- No function changes since last submit
- rebase on the latest PKS kernel support:
- add MSR_IA32_PKRS to the vmx_possible_passthrough_msrs[]
- RFC v2: https://lore.kernel.org/lkml/20201014021157.18022-1-chenyi.qiang@xxxxxxxxx/

- rebase on the latest PKS kernel support:
- add a kvm-unit-tests for PKS
- add the check in kvm_init_msr_list for PKRS
- place the X86_CR4_PKS in mmu_role_bits in kvm_set_cr4
- add the support to expose VM_{ENTRY, EXIT}_LOAD_IA32_PKRS in nested
- RFC v1: https://lore.kernel.org/lkml/20200807084841.7112-1-chenyi.qiang@xxxxxxxxx/


Chenyi Qiang (7):
KVM: VMX: Introduce PKS VMCS fields
KVM: VMX: Add proper cache tracking for PKRS
KVM: X86: Expose IA32_PKRS MSR
KVM: MMU: Rename the pkru to pkr
KVM: MMU: Add support for PKS emulation
KVM: VMX: Expose PKS to guest
KVM: VMX: Enable PKS for nested VM

arch/x86/include/asm/kvm_host.h | 17 ++++---
arch/x86/include/asm/vmx.h | 6 +++
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/kvm_cache_regs.h | 7 +++
arch/x86/kvm/mmu.h | 25 +++++----
arch/x86/kvm/mmu/mmu.c | 68 ++++++++++++++-----------
arch/x86/kvm/vmx/capabilities.h | 6 +++
arch/x86/kvm/vmx/nested.c | 41 ++++++++++++++-
arch/x86/kvm/vmx/vmcs.h | 1 +
arch/x86/kvm/vmx/vmcs12.c | 2 +
arch/x86/kvm/vmx/vmcs12.h | 4 ++
arch/x86/kvm/vmx/vmx.c | 89 ++++++++++++++++++++++++++++++---
arch/x86/kvm/vmx/vmx.h | 7 ++-
arch/x86/kvm/x86.c | 6 ++-
arch/x86/kvm/x86.h | 8 +++
arch/x86/mm/pkeys.c | 6 +++
include/linux/pkeys.h | 5 ++
17 files changed, 243 insertions(+), 57 deletions(-)