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SubjectRe: [PATCH 4/5] KVM: SVM: Add correct handling of nested iopm
On 02/25/2010 07:15 PM, Joerg Roedel wrote:
> This patch adds the correct handling of the nested io
> permission bitmap. Old behavior was to not lookup the port
> in the iopm but only reinject an io intercept to the guest.
>
> Signed-off-by: Joerg Roedel<joerg.roedel@amd.com>
> ---
> arch/x86/kvm/svm.c | 25 +++++++++++++++++++++++++
> 1 files changed, 25 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index bb75a44..3859e2c 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -78,6 +78,7 @@ struct nested_state {
>
> /* gpa pointers to the real vectors */
> u64 vmcb_msrpm;
> + u64 vmcb_iopm;
>
> /* A VMEXIT is required but not yet emulated */
> bool exit_required;
> @@ -1603,6 +1604,26 @@ static void nested_svm_unmap(struct page *page)
> kvm_release_page_dirty(page);
> }
>
> +static int nested_svm_intercept_ioio(struct vcpu_svm *svm)
> +{
> + unsigned port;
> + u8 val, bit;
> + u64 gpa;
> +
> + if (!(svm->nested.intercept& (1ULL<< INTERCEPT_IOIO_PROT)))
> + return NESTED_EXIT_HOST;
> +
> + port = svm->vmcb->control.exit_info_1>> 16;
> + gpa = svm->nested.vmcb_iopm + (port / 8);
> + bit = port % 8;
> + val = 0;
> +
> + if (kvm_read_guest(svm->vcpu.kvm, gpa,&val, 1))
> + val&= (1<< bit);
> +
> + return val ? NESTED_EXIT_DONE : NESTED_EXIT_HOST;
> +}
> +
>

A kvm_{test,set,clear}_guest_bit() would be useful, we have several
users already (not a requirement for this patchset).

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.



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