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Thu, 10 Oct 2024 11:26:00 -0700 (PDT) Date: Thu, 10 Oct 2024 11:23:35 -0700 In-Reply-To: <20241010182427.1434605-1-seanjc@google.com> Mime-Version: 1.0 References: <20241010182427.1434605-1-seanjc@google.com> X-Mailer: git-send-email 2.47.0.rc1.288.g06298d1525-goog Message-ID: <20241010182427.1434605-34-seanjc@google.com> Subject: [PATCH v13 33/85] KVM: Pass in write/dirty to kvm_vcpu_map(), not kvm_vcpu_unmap() From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, " =?utf-8?q?Alex_Benn=C3=A9e?= " , Yan Zhao , David Matlack , David Stevens , Andrew Jones X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241010_112602_607528_3192C04A X-CRM114-Status: GOOD ( 16.44 ) X-Spam-Score: -9.5 (---------) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Now that all kvm_vcpu_{,un}map() users pass "true" for @dirty, have them pass "true" as a @writable param to kvm_vcpu_map(), and thus create a read-only mapping when possible. Note, creating read-only mappings can be theoretically slower, as they don't play nice with fast GUP due to the need to break CoW before mapping the underlying PFN. But practically speaking, creating [...] Content analysis details: (-9.5 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:114a listed in] [list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM welcome-list -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.0 DKIMWL_WL_MED DKIMwl.org - Medium trust sender X-BeenThere: kvm-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Sean Christopherson Sender: "kvm-riscv" Errors-To: kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Now that all kvm_vcpu_{,un}map() users pass "true" for @dirty, have them pass "true" as a @writable param to kvm_vcpu_map(), and thus create a read-only mapping when possible. Note, creating read-only mappings can be theoretically slower, as they don't play nice with fast GUP due to the need to break CoW before mapping the underlying PFN. But practically speaking, creating a mapping isn't a super hot path, and getting a writable mapping for reading is weird and confusing. Tested-by: Alex Bennée Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/nested.c | 4 ++-- arch/x86/kvm/svm/sev.c | 2 +- arch/x86/kvm/svm/svm.c | 8 ++++---- arch/x86/kvm/vmx/nested.c | 16 ++++++++-------- include/linux/kvm_host.h | 20 ++++++++++++++++++-- virt/kvm/kvm_main.c | 12 +++++++----- 6 files changed, 40 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index d5314cb7dff4..9f9478bdecfc 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -922,7 +922,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu) nested_svm_vmexit(svm); out: - kvm_vcpu_unmap(vcpu, &map, true); + kvm_vcpu_unmap(vcpu, &map); return ret; } @@ -1126,7 +1126,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm) vmcb12->control.exit_int_info_err, KVM_ISA_SVM); - kvm_vcpu_unmap(vcpu, &map, true); + kvm_vcpu_unmap(vcpu, &map); nested_svm_transition_tlb_flush(vcpu); diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 0b851ef937f2..4557ff3804ae 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3468,7 +3468,7 @@ void sev_es_unmap_ghcb(struct vcpu_svm *svm) sev_es_sync_to_ghcb(svm); - kvm_vcpu_unmap(&svm->vcpu, &svm->sev_es.ghcb_map, true); + kvm_vcpu_unmap(&svm->vcpu, &svm->sev_es.ghcb_map); svm->sev_es.ghcb = NULL; } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9df3e1e5ae81..c1e29307826b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2299,7 +2299,7 @@ static int vmload_vmsave_interception(struct kvm_vcpu *vcpu, bool vmload) svm_copy_vmloadsave_state(vmcb12, svm->vmcb); } - kvm_vcpu_unmap(vcpu, &map, true); + kvm_vcpu_unmap(vcpu, &map); return ret; } @@ -4714,7 +4714,7 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram) svm_copy_vmrun_state(map_save.hva + 0x400, &svm->vmcb01.ptr->save); - kvm_vcpu_unmap(vcpu, &map_save, true); + kvm_vcpu_unmap(vcpu, &map_save); return 0; } @@ -4774,9 +4774,9 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram) svm->nested.nested_run_pending = 1; unmap_save: - kvm_vcpu_unmap(vcpu, &map_save, true); + kvm_vcpu_unmap(vcpu, &map_save); unmap_map: - kvm_vcpu_unmap(vcpu, &map, true); + kvm_vcpu_unmap(vcpu, &map); return ret; } diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index ff83b56fe2fa..259fe445e695 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -231,7 +231,7 @@ static inline void nested_release_evmcs(struct kvm_vcpu *vcpu) struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu); - kvm_vcpu_unmap(vcpu, &vmx->nested.hv_evmcs_map, true); + kvm_vcpu_unmap(vcpu, &vmx->nested.hv_evmcs_map); vmx->nested.hv_evmcs = NULL; vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID; @@ -318,9 +318,9 @@ static void nested_put_vmcs12_pages(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map, true); - kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true); - kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true); + kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map); + kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map); + kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map); vmx->nested.pi_desc = NULL; } @@ -624,7 +624,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, int msr; unsigned long *msr_bitmap_l1; unsigned long *msr_bitmap_l0 = vmx->nested.vmcs02.msr_bitmap; - struct kvm_host_map msr_bitmap_map; + struct kvm_host_map map; /* Nothing to do if the MSR bitmap is not in use. */ if (!cpu_has_vmx_msr_bitmap() || @@ -647,10 +647,10 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, return true; } - if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), &msr_bitmap_map)) + if (kvm_vcpu_map_readonly(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), &map)) return false; - msr_bitmap_l1 = (unsigned long *)msr_bitmap_map.hva; + msr_bitmap_l1 = (unsigned long *)map.hva; /* * To keep the control flow simple, pay eight 8-byte writes (sixteen @@ -714,7 +714,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0, MSR_IA32_FLUSH_CMD, MSR_TYPE_W); - kvm_vcpu_unmap(vcpu, &msr_bitmap_map, false); + kvm_vcpu_unmap(vcpu, &map); vmx->nested.force_msr_bitmap_recalc = false; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 8739b905d85b..9263375d0362 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -285,6 +285,7 @@ struct kvm_host_map { void *hva; kvm_pfn_t pfn; kvm_pfn_t gfn; + bool writable; }; /* @@ -1312,8 +1313,23 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn); struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu); struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn); kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn); -int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_host_map *map); -void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty); + +int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_host_map *map, + bool writable); +void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map); + +static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, + struct kvm_host_map *map) +{ + return __kvm_vcpu_map(vcpu, gpa, map, true); +} + +static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gpa_t gpa, + struct kvm_host_map *map) +{ + return __kvm_vcpu_map(vcpu, gpa, map, false); +} + unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn); unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable); int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, int offset, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 40a59526d466..080740f65061 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3116,7 +3116,8 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_page); -int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map) +int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map, + bool writable) { struct kvm_follow_pfn kfp = { .slot = gfn_to_memslot(vcpu->kvm, gfn), @@ -3130,6 +3131,7 @@ int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map) map->page = NULL; map->hva = NULL; map->gfn = gfn; + map->writable = writable; map->pfn = kvm_follow_pfn(&kfp); if (is_error_noslot_pfn(map->pfn)) @@ -3146,9 +3148,9 @@ int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map) return map->hva ? 0 : -EFAULT; } -EXPORT_SYMBOL_GPL(kvm_vcpu_map); +EXPORT_SYMBOL_GPL(__kvm_vcpu_map); -void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty) +void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map) { if (!map->hva) return; @@ -3160,11 +3162,11 @@ void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty) memunmap(map->hva); #endif - if (dirty) + if (map->writable) kvm_vcpu_mark_page_dirty(vcpu, map->gfn); if (map->pinned_page) { - if (dirty) + if (map->writable) kvm_set_page_dirty(map->pinned_page); kvm_set_page_accessed(map->pinned_page); unpin_user_page(map->pinned_page);