pve-kernel-lowlatency-qoup/patches/kernel/0022-KVM-x86-SVM-don-t-save-SVM-state-to-SMRAM-when-VM-is.patch
Thomas Lamprecht d0141aeccb update to v5.15.83
with v5.15.78 from ubuntu's master-next and the v5.15.78..v5.15.83
part cherry-picked from upstream stable linux-5.15.y branch

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
2022-12-14 14:07:14 +01:00

41 lines
1.3 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <mlevitsk@redhat.com>
Date: Wed, 3 Aug 2022 18:50:10 +0300
Subject: [PATCH] KVM: x86: SVM: don't save SVM state to SMRAM when VM is not
long mode capable
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>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
arch/x86/kvm/svm/svm.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 8742bb38b40f..b11f03673d07 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4308,6 +4308,15 @@ 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.
+ * SVM should not be enabled by the userspace without marking
+ * the CPU as at least long mode capable.
+ */
+
+ 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;