Re: [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 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:

Hi Jack - can you be more specific about the failing tests? What type of environment and which tests failed, which version of kvm-unit-tests? Do you have any logs available? I ask because we do run kvm-unit-tests on x86 and arm64 but we did not see these regressions.

Thanks, Dan

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()")

Regards, Jack Wang 1 & 1 IONOS SE