linux-kernel - [PATCH v7 0/3] Expose VMFUNC to the nested hypervisor

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Date:   Thu,  3 Aug 2017 15:54:40 -0400
From:   Bandan Das <bsd@...hat.com>
To:     kvm@...r.kernel.org
Cc:     pbonzini@...hat.com, david@...hat.com, rkrcmar@...hat.com,
        jmattson@...gle.com, linux-kernel@...r.kernel.org
Subject: [PATCH v7 0/3] Expose VMFUNC to the nested hypervisor

v7:
 3/3:
  Fix check for AD
  Use kvm_vcpu_read_guest_page()

v6:
 https://lkml.org/lkml/2017/8/1/1015
 3/3:
   Fix check for memory type in address
   Change check function name as requested in the review
   Move setting of mmu->ept_ad to after calling mmu_unload
   and also reset base_role.ad_disabled appropriately
   Replace IS_ALIGN with page_address_valid()

v5:
 https://lkml.org/lkml/2017/7/28/621
 1/3 and 2/3 are unchanged but some changes in 3/3. I left
 the mmu_load failure path untouched because I am not sure what's
 the right thing to do here.
 3/3:
    Move the eptp switching logic to a different function
    Add check for EPTP_ADDRESS in check_vmentry_prereq
    Add check for validity of ept pointer
    Check if AD bit is set and set ept_ad
    Add TODO item about mmu_unload failure

v4:
 https://lkml.org/lkml/2017/7/10/705
 2/3:  Use WARN_ONCE to avoid logging dos

v3:
 https://lkml.org/lkml/2017/7/10/684
 3/3: Add missing nested_release_page_clean() and check the
 eptp as mentioned in SDM 24.6.14

v2:
 https://lkml.org/lkml/2017/7/6/813
 1/3: Patch to enable vmfunc on the host but cause a #UD if
      L1 tries to use it directly. (new)
 2/3: Expose vmfunc to the nested hypervisor, but no vm functions
      are exposed and L0 emulates a vmfunc vmexit to L1. 
 3/3: Force a vmfunc vmexit when L2 tries to use vmfunc and emulate
      eptp switching. Unconditionally expose EPTP switching to the
      L1 hypervisor since L0 fakes eptp switching via a mmu reload.

These patches expose eptp switching/vmfunc to the nested hypervisor.
vmfunc is enabled in the secondary controls for the host and is
exposed to the nested hypervisor. However, if the nested hypervisor
decides to use eptp switching, L0 emulates it.

v1:
 https://lkml.org/lkml/2017/6/29/958

Bandan Das (3):
  KVM: vmx: Enable VMFUNCs
  KVM: nVMX: Enable VMFUNC for the L1 hypervisor
  KVM: nVMX: Emulate EPTP switching for the L1 hypervisor

 arch/x86/include/asm/vmx.h |   9 +++
 arch/x86/kvm/vmx.c         | 185 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 192 insertions(+), 2 deletions(-)

-- 
2.9.4