[PATCH v3 0/9] KVM: nSVM: fixes for CR3/MMU switch upon nested guest entry/exit

Vitaly Kuznetsov
2020-07-09T14:54:10Z

This is a successor of "[PATCH v2 0/3] KVM: nSVM: fix #TF from CR3 switch
when entering guest" and "[PATCH] KVM: x86: drop erroneous mmu_check_root()
from fast_pgd_switch()".

The snowball is growing fast! It all started with an intention to fix
the particular 'tripple fault' issue (now fixed by PATCH7) but now we
also get rid of unconditional kvm_mmu_reset_context() upon nested guest
entry/exit and make the code resemble nVMX. There is still a huge room
for further improvement (proper error propagation, removing unconditional
MMU sync/TLB flush,...) but at least we're making some progress.

Tested with kvm selftests/kvm-unit-tests and by running nested Hyper-V
on KVM. The series doesn't seem to introduce any new issues.

Vitaly Kuznetsov (9):
KVM: nSVM: split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu()
KVM: nSVM: stop dereferencing vcpu->arch.mmu to get the context in
kvm_init_shadow{,_npt}_mmu()
KVM: nSVM: reset nested_run_pending upon nested_svm_vmrun_msrpm()
failure
KVM: nSVM: prepare to handle errors from enter_svm_guest_mode()
KVM: nSVM: introduce nested_svm_load_cr3()
KVM: nSVM: move kvm_set_cr3() after nested_svm_uninit_mmu_context()
KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest
switch
KVM: nSVM: use nested_svm_load_cr3() on guest->host switch
KVM: x86: drop superfluous mmu_check_root() from fast_pgd_switch()

arch/x86/kvm/mmu.h | 3 +-
arch/x86/kvm/mmu/mmu.c | 39 ++++++++++----
arch/x86/kvm/svm/nested.c | 108 ++++++++++++++++++++++++++++----------
arch/x86/kvm/svm/svm.c | 6 ++-
arch/x86/kvm/svm/svm.h | 4 +-
5 files changed, 116 insertions(+), 44 deletions(-)

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