When nested NPT is enabled and KVM_SET_NESTED_STATE is used to restore an
old checkpoint (without a valid gPAT), the current IA32_PAT value must be
used as L2's gPAT.
The current IA32_PAT value may be restored by KVM_SET_MSRS after
KVM_SET_NESTED_STATE. Furthermore, there may be a KVM_GET_NESTED_STATE
before the first KVM_RUN.
Introduce a new boolean, svm->nested.legacy_gpat_semantics. When set, hPAT
updates are also applied to gPAT, preserving the old behavior where L2
shared L1's PAT. svm_vcpu_pre_run() clears this boolean at the first
KVM_RUN.
Signed-off-by: Jim Mattson <jmattson@google.com>
---
arch/x86/kvm/svm/nested.c | 11 ++++++++---
arch/x86/kvm/svm/svm.c | 2 ++
arch/x86/kvm/svm/svm.h | 9 +++++++++
3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 3f512fb630db..a7d6fc1382a7 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1936,9 +1936,14 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
if (ret)
goto out_free;
- if (nested_npt_enabled(svm) &&
- (kvm_state->hdr.svm.flags & KVM_STATE_SVM_VALID_GPAT))
- svm_set_gpat(svm, kvm_state->hdr.svm.gpat);
+ if (nested_npt_enabled(svm)) {
+ if (kvm_state->hdr.svm.flags & KVM_STATE_SVM_VALID_GPAT) {
+ svm_set_gpat(svm, kvm_state->hdr.svm.gpat);
+ } else {
+ svm_set_gpat(svm, vcpu->arch.pat);
+ svm->nested.legacy_gpat_semantics = true;
+ }
+ }
svm->nested.force_msr_bitmap_recalc = true;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b62c32c3942d..a6a44deec82b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4239,6 +4239,8 @@ static int svm_vcpu_pre_run(struct kvm_vcpu *vcpu)
if (to_kvm_sev_info(vcpu->kvm)->need_init)
return -EINVAL;
+ to_svm(vcpu)->nested.legacy_gpat_semantics = false;
+
return 1;
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a0e94a2c51a1..a559cd45c8a9 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -221,6 +221,13 @@ struct svm_nested_state {
* on its side.
*/
bool force_msr_bitmap_recalc;
+
+ /*
+ * Indicates that a legacy nested state was restored (without a
+ * valid gPAT). In this mode, updates to hPAT are also applied to
+ * gPAT, preserving the old behavior where L2 shared L1's PAT.
+ */
+ bool legacy_gpat_semantics;
};
struct vcpu_sev_es_state {
@@ -604,6 +611,8 @@ static inline void svm_set_hpat(struct vcpu_svm *svm, u64 data)
if (is_guest_mode(&svm->vcpu) && !nested_npt_enabled(svm))
svm_set_vmcb_gpat(svm->nested.vmcb02.ptr, data);
}
+ if (svm->nested.legacy_gpat_semantics)
+ svm_set_gpat(svm, data);
}
static inline bool nested_vnmi_enabled(struct vcpu_svm *svm)
--
2.53.0.rc2.204.g2597b5adb4-goog