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From: bugzilla-daemon@bugzilla.kernel.org
To: kvm@vger.kernel.org
Subject: [Bug 53701] New: nVMX: Unchecked setting of cr4 for nested guest
Date: Tue, 12 Feb 2013 08:49:26 +0000 (UTC)	[thread overview]
Message-ID: <bug-53701-28872@https.bugzilla.kernel.org/> (raw)

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: virtualization_kvm@kernel-bugs.osdl.org
        ReportedBy: nyh@math.technion.ac.il
        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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             reply	other threads:[~2013-02-12  8:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-12  8:49 bugzilla-daemon [this message]
2013-02-12  8:50 ` [Bug 53701] nVMX: Unchecked setting of cr4 for nested guest bugzilla-daemon
2015-03-17  3:53 ` bugzilla-daemon

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