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    SubjectRe: [PATCH 4.19 067/306] KVM: nVMX: move check_vmentry_postreqs() call to nested_vmx_enter_non_root_mode()
    On Mon, Dec 02, 2019 at 04:09:33PM +0100, Paolo Bonzini wrote:
    > On 02/12/19 15:51, Greg Kroah-Hartman wrote:
    > > On Mon, Dec 02, 2019 at 03:40:04PM +0100, Jack Wang wrote:
    > >> Greg Kroah-Hartman <gregkh@linuxfoundation.org> 于2019年11月27日周三 下午10:30写道:
    > >>>
    > >>> From: Sean Christopherson <sean.j.christopherson@intel.com>
    > >>>
    > >>> [ Upstream commit 7671ce21b13b9596163a29f4712cb2451a9b97dc ]
    > >>>
    > >>> In preparation of supporting checkpoint/restore for nested state,
    > >>> commit ca0bde28f2ed ("kvm: nVMX: Split VMCS checks from nested_vmx_run()")
    > >>> modified check_vmentry_postreqs() to only perform the guest EFER
    > >>> consistency checks when nested_run_pending is true. But, in the
    > >>> normal nested VMEntry flow, nested_run_pending is only set after
    > >>> check_vmentry_postreqs(), i.e. the consistency check is being skipped.
    > >>>
    > >>> Alternatively, nested_run_pending could be set prior to calling
    > >>> check_vmentry_postreqs() in nested_vmx_run(), but placing the
    > >>> consistency checks in nested_vmx_enter_non_root_mode() allows us
    > >>> to split prepare_vmcs02() and interleave the preparation with
    > >>> the consistency checks without having to change the call sites
    > >>> of nested_vmx_enter_non_root_mode(). In other words, the rest
    > >>> of the consistency check code in nested_vmx_run() will be joining
    > >>> the postreqs checks in future patches.
    > >>>
    > >>> Fixes: ca0bde28f2ed ("kvm: nVMX: Split VMCS checks from nested_vmx_run()")
    > >>> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
    > >>> Cc: Jim Mattson <jmattson@google.com>
    > >>> Reviewed-by: Jim Mattson <jmattson@google.com>
    > >>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    > >>> Signed-off-by: Sasha Levin <sashal@kernel.org>
    > >>> ---
    > >>> arch/x86/kvm/vmx.c | 10 +++-------
    > >>> 1 file changed, 3 insertions(+), 7 deletions(-)
    > >>>
    > >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
    > >>> index fe7fdd666f091..bdf019f322117 100644
    > >>> --- a/arch/x86/kvm/vmx.c
    > >>> +++ b/arch/x86/kvm/vmx.c
    > >>> @@ -12694,6 +12694,9 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu *vcpu, u32 *exit_qual)
    > >>> if (likely(!evaluate_pending_interrupts) && kvm_vcpu_apicv_active(vcpu))
    > >>> evaluate_pending_interrupts |= vmx_has_apicv_interrupt(vcpu);
    > >>>
    > >>> + if (from_vmentry && check_vmentry_postreqs(vcpu, vmcs12, exit_qual))
    > >>> + return EXIT_REASON_INVALID_STATE;
    > >>> +
    > >>> enter_guest_mode(vcpu);
    > >>>
    > >>> if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
    > >>> @@ -12836,13 +12839,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
    > >>> */
    > >>> skip_emulated_instruction(vcpu);
    > >>>
    > >>> - ret = check_vmentry_postreqs(vcpu, vmcs12, &exit_qual);
    > >>> - if (ret) {
    > >>> - nested_vmx_entry_failure(vcpu, vmcs12,
    > >>> - EXIT_REASON_INVALID_STATE, exit_qual);
    > >>> - return 1;
    > >>> - }
    > >>> -
    > >>> /*
    > >>> * We're finally done with prerequisite checking, and can start with
    > >>> * the nested entry.
    > >>> --
    > >>> 2.20.1
    > >>>
    > >>>
    > >>>
    > >> Hi all,
    > >>
    > >> This commit caused many kvm-unit-tests regression, cherry-pick
    > >> following commits from 4.20 fix the regression:
    > >> d63907dc7dd1 ("KVM: nVMX: rename enter_vmx_non_root_mode to
    > >> nested_vmx_enter_non_root_mode")
    > >> a633e41e7362 ("KVM: nVMX: assimilate nested_vmx_entry_failure() into
    > >> nested_vmx_enter_non_root_mode()")
    > >
    > > Now queued up, thanks!
    > >
    > > greg k-h
    > >
    >
    > Why was it backported anyway? Can everybody please just stop applying
    > KVM patches to stable kernels unless CCed to stable@vger.kernel.org?
    >
    > I thought I had already asked Sasha to opt out of the autoselect
    > nonsense after catching another bug that would have been introduced.

    Sasha, can you add kvm code to the blacklist? Odds are the fact that
    this is burried down in arch/x86/ it didn't get caught by the blacklist.

    thanks,

    greg k-h

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