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New: nVMX: Unchecked setting of cr4 for nested guest

Bug 53701 [email protected] 1 participant 3 messages Feb 12, 2013 – Mar 17, 2015 KVM

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https://bugzilla.kernel.org/show_bug.cgi?id=53701

Summary: nVMX: Unchecked setting of cr4 for nested guest
Product: Virtualization
Version: unspecified
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: enhancement
Priority: P1
Component: kvm
AssignedTo: [email protected]
ReportedBy: [email protected]
Regression: No

On 29 May 2012, Avi Kivity wrote on the KVM mailing list:

It looks like the lines

        vmx_set_cr0(vcpu, vmcs12->guest_cr0);
        vmcs_writel(CR0_READ_SHADOW, nested_read_cr0(vmcs12));

        vmx_set_cr4(vcpu, vmcs12->guest_cr4);
        vmcs_writel(CR4_READ_SHADOW, nested_read_cr4(vmcs12));

in prepare_vmcs02() are too dangerous. They only let the hardware check cr4, but not software, so a future cr4 bit which is not handled correctly by kvm can be set in a nested guest. L1 appears to be protected, we use kvm_set_cr4().

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#1 lore raw

[Bug 53701] nVMX: Unchecked setting of cr4 for nested guest

https://bugzilla.kernel.org/show_bug.cgi?id=53701

Nadav Har'El <[email protected]> changed:

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             Blocks|                            |53601
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