On 09/08/19 18:00, Adalbert Lazăr wrote:
> It should complete the commit fd34a9518173 ("kvm: x86: consult the page tracking from kvm_mmu_get_page() and __direct_map()")
>
> Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 65b6acba82da..fd64cf1115da 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2660,6 +2660,9 @@ static void clear_sp_write_flooding_count(u64 *spte)
> static unsigned int kvm_mmu_page_track_acc(struct kvm_vcpu *vcpu, gfn_t gfn,
> unsigned int acc)
> {
> + if (!kvmi_tracked_gfn(vcpu, gfn))
> + return acc;
> +
> if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_PREREAD))
> acc &= ~ACC_USER_MASK;
> if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_PREWRITE) ||
>
If this patch is always needed, then the function should be named
something like kvm_mmu_apply_introspection_access and kvmi_tracked_gfn
should be tested from the moment it is introduced.
But the commit message says nothing about _why_ it is needed, so I
cannot guess. I would very much avoid it however. Is it just an
optimization?
Paolo
