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KVM: x86: SVM: don't save SVM state to SMRAM when VM is not long mode capable

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When the guest CPUID doesn't have support for long mode, 32 bit SMRAM
layout is used and it has no support for preserving EFER and/or SVM
state.

Note that this isn't relevant to running 32 bit guests on VM which is
long mode capable - such VM can still run 32 bit guests in compatibility
mode.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221025124741.228045-23-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2022-10-25 15:47:40 +03:00 committed by Paolo Bonzini
parent dd5045fed5
commit 95504c7c98
1 changed files with 8 additions and 0 deletions
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8
arch/x86/kvm/svm/svm.c
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@ -4410,6 +4410,14 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)
if (!is_guest_mode(vcpu))
return 0;
/*
* 32-bit SMRAM format doesn't preserve EFER and SVM state. Userspace is
* responsible for ensuring nested SVM and SMIs are mutually exclusive.
*/
if (!guest_cpuid_has(vcpu, X86_FEATURE_LM))
return 1;
smram->smram64.svm_guest_flag = 1;
smram->smram64.svm_guest_vmcb_gpa = svm->nested.vmcb12_gpa;