On Wed, Sep 21, 2022 at 10:35:43AM -0700,
David Matlack <dmatlack@xxxxxxxxxx> wrote:
> Move the initialization of fault.{gfn,slot} earlier in the page fault
> handling code for fully direct MMUs. This will enable a future commit to
> split out TDP MMU page fault handling without needing to duplicate the
> initialization of these 2 fields.
>
> Opportunistically take advantage of the fact that fault.gfn is
> initialized in kvm_tdp_page_fault() rather than recomputing it from
> fault->addr.
>
> No functional change intended.
>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/mmu.c | 5 +----
> arch/x86/kvm/mmu/mmu_internal.h | 5 +++++
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index e3b248385154..dc203973de83 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4241,9 +4241,6 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
> bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
> int r;
>
> - fault->gfn = fault->addr >> PAGE_SHIFT;
> - fault->slot = kvm_vcpu_gfn_to_memslot(vcpu, fault->gfn);
> -
> if (page_fault_handle_page_track(vcpu, fault))
> return RET_PF_EMULATE;
>
> @@ -4347,7 +4344,7 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
> if (shadow_memtype_mask && kvm_arch_has_noncoherent_dma(vcpu->kvm)) {
> for ( ; fault->max_level > PG_LEVEL_4K; --fault->max_level) {
> int page_num = KVM_PAGES_PER_HPAGE(fault->max_level);
> - gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1);
> + gfn_t base = fault->gfn & ~(page_num - 1);
>
> if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
> break;
> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> index 1c0a1e7c796d..1e91f24bd865 100644
> --- a/arch/x86/kvm/mmu/mmu_internal.h
> +++ b/arch/x86/kvm/mmu/mmu_internal.h
> @@ -279,6 +279,11 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
> };
> int r;
>
> + if (vcpu->arch.mmu->root_role.direct) {
> + fault.gfn = fault.addr >> PAGE_SHIFT;
> + fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
> + }
> +
> /*
> * Async #PF "faults", a.k.a. prefetch faults, are not faults from the
> * guest perspective and have already been counted at the time of the
> --
> 2.37.3.998.g577e59143f-goog
>
Reviewed-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
