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Patch "KVM: nVMX: fix nested EPT detection" has been added to the 4.10-stable tree

PATCH [email protected] 1 participant 1 message Apr 1, 2017

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This is a note to let you know that I've just added the patch titled

KVM: nVMX: fix nested EPT detection

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kvm-nvmx-fix-nested-ept-detection.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 7ad658b693536741c37b16aeb07840a2ce75f5b9 Mon Sep 17 00:00:00 2001

From: Ladi Prosek <[email protected]>
Date: Thu, 23 Mar 2017 07:18:08 +0100
Subject: KVM: nVMX: fix nested EPT detection

From: Ladi Prosek <[email protected]>

commit 7ad658b693536741c37b16aeb07840a2ce75f5b9 upstream.

The nested_ept_enabled flag introduced in commit 7ca29de2136 was not computed correctly. We are interested only in L1's EPT state, not the the combined L0+L1 value.

In particular, if L0 uses EPT but L1 does not, nested_ept_enabled must be false to make sure that PDPSTRs are loaded based on CR3 as usual, because the special case described in 26.3.2.4 Loading Page-Directory- Pointer-Table Entries does not apply.

Fixes 7ca29de21362 ("KVM: nVMX: fix CR3 load if L2 uses PAE paging and EPT")
Cc [email protected]
Reported-by Wanpeng Li <[email protected]>
Reviewed-by David Hildenbrand <[email protected]>
Signed-off-by Ladi Prosek <[email protected]>
Signed-off-by Paolo Bonzini <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/kvm/vmx.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
arch/x86/kvm/vmx.c +1 -3
@@ -10027,7 +10027,6 @@ static int prepare_vmcs02(struct kvm_vcp
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 exec_control;
-	bool nested_ept_enabled = false;
 
 	vmcs_write16(GUEST_ES_SELECTOR, vmcs12->guest_es_selector);
 	vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector);

@@ -10192,7 +10191,6 @@ static int prepare_vmcs02(struct kvm_vcp
 				vmcs12->guest_intr_status);
 		}
 
-		nested_ept_enabled = (exec_control & SECONDARY_EXEC_ENABLE_EPT) != 0;
 		vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
 	}
 

@@ -10344,7 +10342,7 @@ static int prepare_vmcs02(struct kvm_vcp
 	vmx_set_efer(vcpu, vcpu->arch.efer);
 
 	/* Shadow page tables on either EPT or shadow page tables. */
-	if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3, nested_ept_enabled,
+	if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3, nested_cpu_has_ept(vmcs12),
 				entry_failure_code))
 		return 1;

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/kvm-nvmx-fix-nested-ept-detection.patch