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SubjectRe: [PATCH v5 0/7] KVM: PKS Virtualization support
From
On 11/08/21 12:11, Chenyi Qiang wrote:
> This patch series is based on top of kernel patchset:
> https://lore.kernel.org/lkml/20210804043231.2655537-1-ira.weiny@intel.com/
>
> 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.

Hi Chenyi,

pkrs_cache does not yet exist in Linux 5.15. What is the state of the
bare-metal support for PKS?

Thanks,

Paolo

>
> ---
>
> Changelogs:
>
> v4->v5
> - 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@intel.com/
>
> v3->v4
> - 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@intel.com/
>
> v2->v3:
> - No function changes since last submit
> - rebase on the latest PKS kernel support:
> https://lore.kernel.org/lkml/20201102205320.1458656-1-ira.weiny@intel.com/
> - add MSR_IA32_PKRS to the vmx_possible_passthrough_msrs[]
> - RFC v2: https://lore.kernel.org/lkml/20201014021157.18022-1-chenyi.qiang@intel.com/
>
> v1->v2:
> - rebase on the latest PKS kernel support:
> https://github.com/weiny2/linux-kernel/tree/pks-rfc-v3
> - 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
> VMX MSR
> - RFC v1: https://lore.kernel.org/lkml/20200807084841.7112-1-chenyi.qiang@intel.com/
>
> ---
>
> 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(-)
>

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