From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH v2 0/5] Fix EFER.NX=0 with EPT
Date: Thu, 6 May 2010 16:43:17 -0300 [thread overview]
Message-ID: <20100506194317.GC3432@amt.cnet> (raw)
In-Reply-To: <1272793734-455-1-git-send-email-avi@redhat.com>
On Sun, May 02, 2010 at 12:48:49PM +0300, Avi Kivity wrote:
> Currently we run with EFER.NX=1 on the guest even if the guest value is 0.
> This is fine with shadow, since we check bit 63 when instantiating a page
> table, and fault if bit 63 is set while EFER.NX is clear.
>
> This doesn't work with EPT, since we no longer get the change to check guest
> ptes. So we need to run with EFER.NX=0.
>
> This is complicated by the fact that if we switch EFER.NX on the host, we'll
> trap immediately, since some host pages are mapped with the NX bit set. As
> a result, we need to switch the MSR atomically during guest entry and exit.
>
> This patchset implements the complications described above.
>
> v2:
> Fix transition from long mode to legacy mode
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
prev parent reply other threads:[~2010-05-06 20:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-02 9:48 [PATCH v2 0/5] Fix EFER.NX=0 with EPT Avi Kivity
2010-05-02 9:48 ` [PATCH v2 1/5] KVM: Let vcpu structure alignment be determined at runtime Avi Kivity
2010-05-02 9:48 ` [PATCH v2 2/5] KVM: VMX: Add definition for msr autoload entry Avi Kivity
2010-05-02 9:48 ` [PATCH v2 3/5] KVM: VMX: Add definitions for guest and host EFER autoswitch vmcs entries Avi Kivity
2010-05-02 9:48 ` [PATCH v2 4/5] KVM: VMX: Add facility to atomically switch MSRs on guest entry/exit Avi Kivity
2010-05-02 9:48 ` [PATCH v2 5/5] KVM: VMX: Atomically switch efer if EPT && !EFER.NX Avi Kivity
2010-05-06 19:43 ` Marcelo Tosatti [this message]
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