| Message ID | 20220321224358.1305530-9-bgardon@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86/MMU: Optimize disabling dirty logging | expand |
On Mon, Mar 21, 2022, Ben Gardon wrote: > Export kvm_is_mmio_pfn from spte.c. It will be used in a subsequent > commit for in-place lpage promotion when disabling dirty logging. Rather than force the promotion path to call kvm_is_mmio_pfn(), what about: a. Truly exporting the helper, i.e. EXPORT_SYMBOL_GPL b. Move this patch earlier in the series, before "KVM: x86/mmu: Factor out part of vmx_get_mt_mask which does not depend on vcpu" c. In the same patch, drop the "is_mmio" param from kvm_x86_ops.get_mt_mask() and have vmx_get_mt_mask() call it directly. That way the call to kvm_is_mmio_pfn() is avoided when running on AMD hosts (ignoring the shadow_me_mask thing, which I have a separate tweak for). The worst case scenario for a lookup is actually quite expensive, e.g. retpoline and a spinlock. > Signed-off-by: Ben Gardon <bgardon@google.com> > --- > arch/x86/kvm/mmu/spte.c | 2 +- > arch/x86/kvm/mmu/spte.h | 1 + > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c > index 45e9c0c3932e..8e9b827c4ed5 100644 > --- a/arch/x86/kvm/mmu/spte.c > +++ b/arch/x86/kvm/mmu/spte.c > @@ -69,7 +69,7 @@ u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access) > return spte; > } > > -static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) > +bool kvm_is_mmio_pfn(kvm_pfn_t pfn) > { > if (pfn_valid(pfn)) > return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) && > diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h > index cee02fe63429..e058a85e6c66 100644 > --- a/arch/x86/kvm/mmu/spte.h > +++ b/arch/x86/kvm/mmu/spte.h > @@ -443,4 +443,5 @@ u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn); > > void kvm_mmu_reset_all_pte_masks(void); > > +bool kvm_is_mmio_pfn(kvm_pfn_t pfn); > #endif > -- > 2.35.1.894.gb6a874cedc-goog >
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 45e9c0c3932e..8e9b827c4ed5 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -69,7 +69,7 @@ u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access) return spte; } -static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) +bool kvm_is_mmio_pfn(kvm_pfn_t pfn) { if (pfn_valid(pfn)) return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) && diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index cee02fe63429..e058a85e6c66 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -443,4 +443,5 @@ u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn); void kvm_mmu_reset_all_pte_masks(void); +bool kvm_is_mmio_pfn(kvm_pfn_t pfn); #endif
Export kvm_is_mmio_pfn from spte.c. It will be used in a subsequent commit for in-place lpage promotion when disabling dirty logging. Signed-off-by: Ben Gardon <bgardon@google.com> --- arch/x86/kvm/mmu/spte.c | 2 +- arch/x86/kvm/mmu/spte.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-)