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[v3,3/7] KVM: x86: reset pdptrs_from_userspace when exiting smm

Message ID 20210913140954.165665-4-mlevitsk@redhat.com (mailing list archive)
State New, archived
Headers show
Series KVM: few more SMM fixes | expand

Commit Message

Maxim Levitsky Sept. 13, 2021, 2:09 p.m. UTC
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 <mlevitsk@redhat.com>
---
 arch/x86/kvm/x86.c | 7 +++++++
 1 file changed, 7 insertions(+)
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Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 86539c1686fa..3a61f19455cb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7654,6 +7654,13 @@  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);