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KVM: x86: clear SMM flags before loading state while leaving SMM 

RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).

Reported-by: Jon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123cb ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2019-04-02 08:03:11 -07:00 committed by Paolo Bonzini
parent c5833c7a43
commit 9ec19493fb
3 changed files with 10 additions and 16 deletions
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12
arch/x86/kvm/emulate.c
View File

@ -2571,6 +2571,12 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
if (ret != X86EMUL_CONTINUE)
return X86EMUL_UNHANDLEABLE;
if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_INSIDE_NMI_MASK) == 0)
ctxt->ops->set_nmi_mask(ctxt, false);
ctxt->ops->set_hflags(ctxt, ctxt->ops->get_hflags(ctxt) &
~(X86EMUL_SMM_INSIDE_NMI_MASK | X86EMUL_SMM_MASK));
/*
* Get back to real mode, to prepare a safe state in which to load
* CR0/CR3/CR4/EFER. It's all a bit more complicated if the vCPU
@ -2624,12 +2630,6 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
return X86EMUL_UNHANDLEABLE;
}
if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_INSIDE_NMI_MASK) == 0)
ctxt->ops->set_nmi_mask(ctxt, false);
ctxt->ops->set_hflags(ctxt, ctxt->ops->get_hflags(ctxt) &
~(X86EMUL_SMM_INSIDE_NMI_MASK | X86EMUL_SMM_MASK));
ctxt->ops->post_leave_smm(ctxt);
return X86EMUL_CONTINUE;

12
arch/x86/kvm/svm.c
View File

@ -6239,21 +6239,17 @@ static int svm_pre_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
struct page *page;
u64 guest;
u64 vmcb;
int ret;
guest = GET_SMSTATE(u64, smstate, 0x7ed8);
vmcb = GET_SMSTATE(u64, smstate, 0x7ee0);
if (guest) {
vcpu->arch.hflags &= ~HF_SMM_MASK;
nested_vmcb = nested_svm_map(svm, vmcb, &page);
if (nested_vmcb)
enter_svm_guest_mode(svm, vmcb, nested_vmcb, page);
else
ret = 1;
vcpu->arch.hflags |= HF_SMM_MASK;
if (!nested_vmcb)
return 1;
enter_svm_guest_mode(svm, vmcb, nested_vmcb, page);
}
return ret;
return 0;
}
static int enable_smi_window(struct kvm_vcpu *vcpu)

2
arch/x86/kvm/vmx/vmx.c
View File

@ -7409,9 +7409,7 @@ static int vmx_pre_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
}
if (vmx->nested.smm.guest_mode) {
vcpu->arch.hflags &= ~HF_SMM_MASK;
ret = nested_vmx_enter_non_root_mode(vcpu, false);
vcpu->arch.hflags |= HF_SMM_MASK;
if (ret)
return ret;