KVM: x86: avoid loading PDPTRs after migration when possible
if new KVM_*_SREGS2 ioctls are used, the PDPTRs are
a part of the migration state and are correctly
restored by those ioctls.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210607090203.133058-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 601e008..3831069 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -862,6 +862,12 @@ struct kvm_vcpu_arch {
/* Protected Guests */
bool guest_state_protected;
+ /*
+ * Set when PDPTS were loaded directly by the userspace without
+ * reading the guest memory
+ */
+ bool pdptrs_from_userspace;
+
#if IS_ENABLED(CONFIG_HYPERV)
hpa_t hv_root_tdp;
#endif
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index e917eba..c902ace 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1367,7 +1367,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu)
if (WARN_ON(!is_guest_mode(vcpu)))
return true;
- if (!nested_npt_enabled(svm) && is_pae_paging(vcpu))
+ if (!vcpu->arch.pdptrs_from_userspace &&
+ !nested_npt_enabled(svm) && is_pae_paging(vcpu))
/*
* Reload the guest's PDPTRs since after a migration
* the guest CR3 might be restored prior to setting the nested
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index ac30667..1a2f000 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3122,7 +3122,8 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
struct page *page;
u64 hpa;
- if (!nested_cpu_has_ept(vmcs12) && is_pae_paging(vcpu)) {
+ if (!vcpu->arch.pdptrs_from_userspace &&
+ !nested_cpu_has_ept(vmcs12) && is_pae_paging(vcpu)) {
/*
* Reload the guest's PDPTRs since after a migration
* the guest CR3 might be restored prior to setting the nested
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8085ab8..1727178 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -820,6 +820,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
memcpy(mmu->pdptrs, pdpte, sizeof(mmu->pdptrs));
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
+ vcpu->arch.pdptrs_from_userspace = false;
+
out:
return ret;
@@ -10265,6 +10267,7 @@ static int __set_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2)
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
mmu_reset_needed = 1;
+ vcpu->arch.pdptrs_from_userspace = true;
}
if (mmu_reset_needed)
kvm_mmu_reset_context(vcpu);