Indeed. Good catch. Thanks :-)
On Thu, Sep 03, 2009 at 04:51:52PM +0200, Alexander Graf wrote:
> Thanks to Joerg's previous series of cleanups, we now have almost all
> information we need to decide what to do on #VMEXIT because we get
> the variables from the VMCB on VMRUN.
>
> Unfortunately there's one piece that slipped through the conversion,
> namely the MSR intercept which still tries to map the nested VMCB
> to find out if MSRs are intercepted.
>
> So let's use the cached value, removing the need for two atomic maps
> (which breaks anyways) and fix an oops along the way.
>
> CC: Joerg Roedel <joerg.roedel@xxxxxxx>
> Signed-off-by: Alexander Graf <agraf@xxxxxxx>
Acked-by: Joerg Roedel <joerg.roedel@xxxxxxx>
>
> ---
>
> v1 -> v2:
>
> - Don't break when MSR is not intercepted
> ---
> arch/x86/kvm/svm.c | 15 ++++++---------
> 1 files changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 2df9b45..a5f90c7 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1427,19 +1427,17 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
> {
> u32 param = svm->vmcb->control.exit_info_1 & 1;
> u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
> - struct vmcb *nested_vmcb;
> bool ret = false;
> u32 t0, t1;
> u8 *msrpm;
>
> - nested_vmcb = nested_svm_map(svm, svm->nested.vmcb, KM_USER0);
> - msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER1);
> + if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
> + return false;
>
> - if (!nested_vmcb || !msrpm)
> - goto out;
> + msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER0);
>
> - if (!(nested_vmcb->control.intercept & (1ULL << INTERCEPT_MSR_PROT)))
> - return 0;
> + if (!msrpm)
> + goto out;
>
> switch (msr) {
> case 0 ... 0x1fff:
> @@ -1464,8 +1462,7 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
> ret = msrpm[t1] & ((1 << param) << t0);
>
> out:
> - nested_svm_unmap(nested_vmcb, KM_USER0);
> - nested_svm_unmap(msrpm, KM_USER1);
> + nested_svm_unmap(msrpm, KM_USER0);
>
> return ret;
> }
> --
> 1.6.0.2
>
>
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