linux-kernel - [PATCH 4.19 043/131] KVM: nVMX: Always sync GUEST

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Date:   Tue, 28 Apr 2020 20:24:15 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Liran Alon <liran.alon@...cle.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Ben Hutchings <ben.hutchings@...ethink.co.uk>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 043/131] KVM: nVMX: Always sync GUEST_BNDCFGS when it comes from vmcs01

From: Sean Christopherson <sean.j.christopherson@...el.com>

commit 3b013a2972d5bc344d6eaa8f24fdfe268211e45f upstream.

If L1 does not set VM_ENTRY_LOAD_BNDCFGS, then L1's BNDCFGS value must
be propagated to vmcs02 since KVM always runs with VM_ENTRY_LOAD_BNDCFGS
when MPX is supported.  Because the value effectively comes from vmcs01,
vmcs02 must be updated even if vmcs12 is clean.

Fixes: 62cf9bd8118c4 ("KVM: nVMX: Fix emulation of VM_ENTRY_LOAD_BNDCFGS")
Cc: Liran Alon <liran.alon@...cle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
[bwh: Backported to 4.19: adjust filename, context]
Signed-off-by: Ben Hutchings <ben.hutchings@...ethink.co.uk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/vmx.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e4d0ad06790e1..ccbddc80ad55f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -12137,13 +12137,9 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 
 	set_cr4_guest_host_mask(vmx);
 
-	if (kvm_mpx_supported()) {
-		if (vmx->nested.nested_run_pending &&
-			(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
-			vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
-		else
-			vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs);
-	}
+	if (kvm_mpx_supported() && vmx->nested.nested_run_pending &&
+	    (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
+		vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
 
 	if (enable_vpid) {
 		if (nested_cpu_has_vpid(vmcs12) && vmx->nested.vpid02)
@@ -12207,6 +12203,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 		kvm_set_dr(vcpu, 7, vcpu->arch.dr7);
 		vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl);
 	}
+	if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending ||
+	    !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)))
+		vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs);
 	if (vmx->nested.nested_run_pending) {
 		vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
 			     vmcs12->vm_entry_intr_info_field);
-- 
2.20.1