| Message ID | 20210924163152.289027-32-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: pass arguments on the page fault path via struct kvm_page_fault | expand |
On Fri, Sep 24, 2021 at 12:31:52PM -0400, Paolo Bonzini wrote: > Pass the old SPTE in the same variable that receives the new SPTE. This > reduces the number of arguments from 11 to 10. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/mmu/mmu.c | 18 ++++++++---------- > arch/x86/kvm/mmu/paging_tmpl.h | 2 +- > arch/x86/kvm/mmu/spte.c | 7 ++++--- > arch/x86/kvm/mmu/spte.h | 2 +- > arch/x86/kvm/mmu/tdp_mmu.c | 9 +++++---- > 5 files changed, 19 insertions(+), 19 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 91292009780a..b363433bcd2c 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -2682,8 +2682,8 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, > int was_rmapped = 0; > int ret = RET_PF_FIXED; > bool flush = false; > + u64 spte = *sptep; > bool wrprot; > - u64 spte; > > /* Prefetching always gets a writable pfn. */ > bool host_writable = !fault || fault->map_writable; > @@ -2691,35 +2691,33 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, > bool write_fault = fault && fault->write; > > pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__, > - *sptep, write_fault, gfn); > + spte, write_fault, gfn); > > if (unlikely(is_noslot_pfn(pfn))) { > mark_mmio_spte(vcpu, sptep, gfn, pte_access); > return RET_PF_EMULATE; > } > > - if (is_shadow_present_pte(*sptep)) { > + if (is_shadow_present_pte(spte)) { > /* > * If we overwrite a PTE page pointer with a 2MB PMD, unlink > * the parent of the now unreachable PTE. > */ > - if (level > PG_LEVEL_4K && !is_large_pte(*sptep)) { > + if (level > PG_LEVEL_4K && !is_large_pte(spte)) { > struct kvm_mmu_page *child; > - u64 pte = *sptep; > - > - child = to_shadow_page(pte & PT64_BASE_ADDR_MASK); > + child = to_shadow_page(spte & PT64_BASE_ADDR_MASK); > drop_parent_pte(child, sptep); > flush = true; > - } else if (pfn != spte_to_pfn(*sptep)) { > + } else if (pfn != spte_to_pfn(spte)) { > pgprintk("hfn old %llx new %llx\n", > - spte_to_pfn(*sptep), pfn); > + spte_to_pfn(spte), pfn); > drop_spte(vcpu->kvm, sptep); > flush = true; > } else > was_rmapped = 1; > } > > - wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, *sptep, speculative, > + wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, speculative, > true, host_writable, &spte); > > if (*sptep == spte) { > diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h > index d8889e02c4b7..88551cfd06c6 100644 > --- a/arch/x86/kvm/mmu/paging_tmpl.h > +++ b/arch/x86/kvm/mmu/paging_tmpl.h > @@ -1130,7 +1130,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) > host_writable = spte & shadow_host_writable_mask; > slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); > make_spte(vcpu, sp, slot, pte_access, gfn, > - spte_to_pfn(spte), spte, true, false, > + spte_to_pfn(spte), true, false, > host_writable, &spte); > > flush |= mmu_spte_update(sptep, spte); > diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c > index 871f6114b0fa..91525388032e 100644 > --- a/arch/x86/kvm/mmu/spte.c > +++ b/arch/x86/kvm/mmu/spte.c > @@ -92,10 +92,11 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) > bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > struct kvm_memory_slot *slot, > unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, > - u64 old_spte, bool speculative, bool can_unsync, > - bool host_writable, u64 *new_spte) > + bool speculative, bool can_unsync, > + bool host_writable, u64 *sptep) I'd prefer a different name since `sptep` has specific meaning throughout the mmu code. (It's the address of the spte in the page table.) Case in point, I was going to suggest we can get rid of struct kvm_mmu_page since it can be derived from the sptep and then realized how wrong that was :). Instead of receiving the new spte as a parameter what do you think about changing make_spte to return the new spte? I think that would make the code more readable (but won't reduce the number of arguments because you'd have to add wrprot). > { > int level = sp->role.level; > + u64 old_spte = *sptep; > u64 spte = SPTE_MMU_PRESENT_MASK; > bool wrprot = false; > > @@ -187,7 +188,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > mark_page_dirty_in_slot(vcpu->kvm, slot, gfn); > } > > - *new_spte = spte; > + *sptep = spte; > return wrprot; > } > > diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h > index 7c0b09461349..231531c6015a 100644 > --- a/arch/x86/kvm/mmu/spte.h > +++ b/arch/x86/kvm/mmu/spte.h > @@ -337,7 +337,7 @@ static inline u64 get_mmio_spte_generation(u64 spte) > bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > struct kvm_memory_slot *slot, > unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, > - u64 old_spte, bool speculative, bool can_unsync, > + bool speculative, bool can_unsync, > bool host_writable, u64 *new_spte); > u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); > u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 953f24ded6bc..29b739c7bba4 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -903,13 +903,14 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, > bool wrprot = false; > > WARN_ON(sp->role.level != fault->goal_level); > - if (unlikely(!fault->slot)) > + if (unlikely(!fault->slot)) { > new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); > - else > + } else { > + new_spte = iter->old_spte; > wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn, > - fault->pfn, iter->old_spte, fault->prefault, true, > + fault->pfn, fault->prefault, true, > fault->map_writable, &new_spte); > - > + } > if (new_spte == iter->old_spte) > ret = RET_PF_SPURIOUS; > else if (!tdp_mmu_set_spte_atomic(vcpu->kvm, iter, new_spte)) > -- > 2.27.0 >
On 29/09/21 01:20, David Matlack wrote: >> bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, >> struct kvm_memory_slot *slot, >> unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, >> - u64 old_spte, bool speculative, bool can_unsync, >> - bool host_writable, u64 *new_spte) >> + bool speculative, bool can_unsync, >> + bool host_writable, u64 *sptep) > I'd prefer a different name since `sptep` has specific meaning > throughout the mmu code. (It's the address of the spte in the page > table.) > > Case in point, I was going to suggest we can get rid of struct > kvm_mmu_page since it can be derived from the sptep and then realized > how wrong that was:). > > Instead of receiving the new spte as a parameter what do you think about > changing make_spte to return the new spte? I think that would make the > code more readable (but won't reduce the number of arguments because > you'd have to add wrprot). > You have a point. I've dropped this patch for now. Paolo
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 91292009780a..b363433bcd2c 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2682,8 +2682,8 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, int was_rmapped = 0; int ret = RET_PF_FIXED; bool flush = false; + u64 spte = *sptep; bool wrprot; - u64 spte; /* Prefetching always gets a writable pfn. */ bool host_writable = !fault || fault->map_writable; @@ -2691,35 +2691,33 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, bool write_fault = fault && fault->write; pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__, - *sptep, write_fault, gfn); + spte, write_fault, gfn); if (unlikely(is_noslot_pfn(pfn))) { mark_mmio_spte(vcpu, sptep, gfn, pte_access); return RET_PF_EMULATE; } - if (is_shadow_present_pte(*sptep)) { + if (is_shadow_present_pte(spte)) { /* * If we overwrite a PTE page pointer with a 2MB PMD, unlink * the parent of the now unreachable PTE. */ - if (level > PG_LEVEL_4K && !is_large_pte(*sptep)) { + if (level > PG_LEVEL_4K && !is_large_pte(spte)) { struct kvm_mmu_page *child; - u64 pte = *sptep; - - child = to_shadow_page(pte & PT64_BASE_ADDR_MASK); + child = to_shadow_page(spte & PT64_BASE_ADDR_MASK); drop_parent_pte(child, sptep); flush = true; - } else if (pfn != spte_to_pfn(*sptep)) { + } else if (pfn != spte_to_pfn(spte)) { pgprintk("hfn old %llx new %llx\n", - spte_to_pfn(*sptep), pfn); + spte_to_pfn(spte), pfn); drop_spte(vcpu->kvm, sptep); flush = true; } else was_rmapped = 1; } - wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, *sptep, speculative, + wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, speculative, true, host_writable, &spte); if (*sptep == spte) { diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index d8889e02c4b7..88551cfd06c6 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -1130,7 +1130,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) host_writable = spte & shadow_host_writable_mask; slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); make_spte(vcpu, sp, slot, pte_access, gfn, - spte_to_pfn(spte), spte, true, false, + spte_to_pfn(spte), true, false, host_writable, &spte); flush |= mmu_spte_update(sptep, spte); diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 871f6114b0fa..91525388032e 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -92,10 +92,11 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct kvm_memory_slot *slot, unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, - u64 old_spte, bool speculative, bool can_unsync, - bool host_writable, u64 *new_spte) + bool speculative, bool can_unsync, + bool host_writable, u64 *sptep) { int level = sp->role.level; + u64 old_spte = *sptep; u64 spte = SPTE_MMU_PRESENT_MASK; bool wrprot = false; @@ -187,7 +188,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, mark_page_dirty_in_slot(vcpu->kvm, slot, gfn); } - *new_spte = spte; + *sptep = spte; return wrprot; } diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 7c0b09461349..231531c6015a 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -337,7 +337,7 @@ static inline u64 get_mmio_spte_generation(u64 spte) bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct kvm_memory_slot *slot, unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, - u64 old_spte, bool speculative, bool can_unsync, + bool speculative, bool can_unsync, bool host_writable, u64 *new_spte); u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 953f24ded6bc..29b739c7bba4 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -903,13 +903,14 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, bool wrprot = false; WARN_ON(sp->role.level != fault->goal_level); - if (unlikely(!fault->slot)) + if (unlikely(!fault->slot)) { new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); - else + } else { + new_spte = iter->old_spte; wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn, - fault->pfn, iter->old_spte, fault->prefault, true, + fault->pfn, fault->prefault, true, fault->map_writable, &new_spte); - + } if (new_spte == iter->old_spte) ret = RET_PF_SPURIOUS; else if (!tdp_mmu_set_spte_atomic(vcpu->kvm, iter, new_spte))
Pass the old SPTE in the same variable that receives the new SPTE. This reduces the number of arguments from 11 to 10. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/mmu/mmu.c | 18 ++++++++---------- arch/x86/kvm/mmu/paging_tmpl.h | 2 +- arch/x86/kvm/mmu/spte.c | 7 ++++--- arch/x86/kvm/mmu/spte.h | 2 +- arch/x86/kvm/mmu/tdp_mmu.c | 9 +++++---- 5 files changed, 19 insertions(+), 19 deletions(-)