From 37687c403a641f251cb2ef2e7830b88aa0647ba9 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Mon, 13 Sep 2021 17:09:50 +0300 Subject: [PATCH] KVM: x86: reset pdptrs_from_userspace when exiting smm When exiting SMM, pdpts are loaded again from the guest memory. This fixes a theoretical bug, when exit from SMM triggers entry to the nested guest which re-uses some of the migration code which uses this flag as a workaround for a legacy userspace. Signed-off-by: Maxim Levitsky Message-Id: <20210913140954.165665-4-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 11017c94f0aa..ba70e8f11f2c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7658,6 +7658,13 @@ static void kvm_smm_changed(struct kvm_vcpu *vcpu, bool entering_smm) /* Process a latched INIT or SMI, if any. */ kvm_make_request(KVM_REQ_EVENT, vcpu); + + /* + * Even if KVM_SET_SREGS2 loaded PDPTRs out of band, + * on SMM exit we still need to reload them from + * guest memory + */ + vcpu->arch.pdptrs_from_userspace = false; } kvm_mmu_reset_context(vcpu); -- GitLab