diff options
-rw-r--r-- | Documentation/virt/kvm/api.rst | 9 | ||||
-rw-r--r-- | arch/arm64/kvm/Kconfig | 1 | ||||
-rw-r--r-- | arch/arm64/kvm/mmu.c | 203 | ||||
-rw-r--r-- | arch/arm64/kvm/nested.c | 41 | ||||
-rw-r--r-- | arch/x86/include/asm/kvm-x86-ops.h | 2 | ||||
-rw-r--r-- | arch/x86/include/asm/kvm_host.h | 6 | ||||
-rw-r--r-- | arch/x86/kvm/Kconfig | 26 | ||||
-rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 142 | ||||
-rw-r--r-- | arch/x86/kvm/mmu/mmu_internal.h | 2 | ||||
-rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 2 | ||||
-rw-r--r-- | arch/x86/kvm/svm/sev.c | 6 | ||||
-rw-r--r-- | arch/x86/kvm/svm/svm.c | 2 | ||||
-rw-r--r-- | arch/x86/kvm/svm/svm.h | 4 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/main.c | 7 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/tdx.c | 5 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/x86_ops.h | 2 | ||||
-rw-r--r-- | arch/x86/kvm/x86.c | 11 | ||||
-rw-r--r-- | include/linux/kvm_host.h | 38 | ||||
-rw-r--r-- | include/uapi/linux/kvm.h | 2 | ||||
-rw-r--r-- | tools/testing/selftests/kvm/Makefile.kvm | 1 | ||||
-rw-r--r-- | tools/testing/selftests/kvm/guest_memfd_test.c | 236 | ||||
-rw-r--r-- | virt/kvm/Kconfig | 15 | ||||
-rw-r--r-- | virt/kvm/Makefile.kvm | 2 | ||||
-rw-r--r-- | virt/kvm/guest_memfd.c | 81 | ||||
-rw-r--r-- | virt/kvm/kvm_main.c | 12 | ||||
-rw-r--r-- | virt/kvm/kvm_mm.h | 4 |
26 files changed, 648 insertions, 214 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 6aa40ee05a4a..c17a87a0a5ac 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6414,6 +6414,15 @@ most one mapping per page, i.e. binding multiple memory regions to a single guest_memfd range is not allowed (any number of memory regions can be bound to a single guest_memfd file, but the bound ranges must not overlap). +When the capability KVM_CAP_GUEST_MEMFD_MMAP is supported, the 'flags' field +supports GUEST_MEMFD_FLAG_MMAP. Setting this flag on guest_memfd creation +enables mmap() and faulting of guest_memfd memory to host userspace. + +When the KVM MMU performs a PFN lookup to service a guest fault and the backing +guest_memfd has the GUEST_MEMFD_FLAG_MMAP set, then the fault will always be +consumed from guest_memfd, regardless of whether it is a shared or a private +fault. + See KVM_SET_USER_MEMORY_REGION2 for additional details. 4.143 KVM_PRE_FAULT_MEMORY diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 713248f240e0..bff62e75d681 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS + select KVM_GUEST_MEMFD help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 1c78864767c5..a36426ccd9b5 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1477,13 +1477,132 @@ static bool kvm_vma_is_cacheable(struct vm_area_struct *vma) } } +static int prepare_mmu_memcache(struct kvm_vcpu *vcpu, bool topup_memcache, + void **memcache) +{ + int min_pages; + + if (!is_protected_kvm_enabled()) + *memcache = &vcpu->arch.mmu_page_cache; + else + *memcache = &vcpu->arch.pkvm_memcache; + + if (!topup_memcache) + return 0; + + min_pages = kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu); + + if (!is_protected_kvm_enabled()) + return kvm_mmu_topup_memory_cache(*memcache, min_pages); + + return topup_hyp_memcache(*memcache, min_pages); +} + +/* + * Potentially reduce shadow S2 permissions to match the guest's own S2. For + * exec faults, we'd only reach this point if the guest actually allowed it (see + * kvm_s2_handle_perm_fault). + * + * Also encode the level of the original translation in the SW bits of the leaf + * entry as a proxy for the span of that translation. This will be retrieved on + * TLB invalidation from the guest and used to limit the invalidation scope if a + * TTL hint or a range isn't provided. + */ +static void adjust_nested_fault_perms(struct kvm_s2_trans *nested, + enum kvm_pgtable_prot *prot, + bool *writable) +{ + *writable &= kvm_s2_trans_writable(nested); + if (!kvm_s2_trans_readable(nested)) + *prot &= ~KVM_PGTABLE_PROT_R; + + *prot |= kvm_encode_nested_level(nested); +} + +#define KVM_PGTABLE_WALK_MEMABORT_FLAGS (KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED) + +static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + struct kvm_s2_trans *nested, + struct kvm_memory_slot *memslot, bool is_perm) +{ + bool write_fault, exec_fault, writable; + enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_MEMABORT_FLAGS; + enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; + struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt; + unsigned long mmu_seq; + struct page *page; + struct kvm *kvm = vcpu->kvm; + void *memcache; + kvm_pfn_t pfn; + gfn_t gfn; + int ret; + + ret = prepare_mmu_memcache(vcpu, true, &memcache); + if (ret) + return ret; + + if (nested) + gfn = kvm_s2_trans_output(nested) >> PAGE_SHIFT; + else + gfn = fault_ipa >> PAGE_SHIFT; + + write_fault = kvm_is_write_fault(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); + + VM_WARN_ON_ONCE(write_fault && exec_fault); + + mmu_seq = kvm->mmu_invalidate_seq; + /* Pairs with the smp_wmb() in kvm_mmu_invalidate_end(). */ + smp_rmb(); + + ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, &page, NULL); + if (ret) { + kvm_prepare_memory_fault_exit(vcpu, fault_ipa, PAGE_SIZE, + write_fault, exec_fault, false); + return ret; + } + + writable = !(memslot->flags & KVM_MEM_READONLY); + + if (nested) + adjust_nested_fault_perms(nested, &prot, &writable); + + if (writable) + prot |= KVM_PGTABLE_PROT_W; + + if (exec_fault || + (cpus_have_final_cap(ARM64_HAS_CACHE_DIC) && + (!nested || kvm_s2_trans_executable(nested)))) + prot |= KVM_PGTABLE_PROT_X; + + kvm_fault_lock(kvm); + if (mmu_invalidate_retry(kvm, mmu_seq)) { + ret = -EAGAIN; + goto out_unlock; + } + + ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault_ipa, PAGE_SIZE, + __pfn_to_phys(pfn), prot, + memcache, flags); + +out_unlock: + kvm_release_faultin_page(kvm, page, !!ret, writable); + kvm_fault_unlock(kvm); + + if (writable && !ret) + mark_page_dirty_in_slot(kvm, memslot, gfn); + + return ret != -EAGAIN ? ret : 0; +} + static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_s2_trans *nested, struct kvm_memory_slot *memslot, unsigned long hva, bool fault_is_perm) { int ret = 0; - bool write_fault, writable, force_pte = false; + bool topup_memcache; + bool write_fault, writable; bool exec_fault, mte_allowed, is_vma_cacheable; bool s2_force_noncacheable = false, vfio_allow_any_uc = false; unsigned long mmu_seq; @@ -1495,28 +1614,19 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, gfn_t gfn; kvm_pfn_t pfn; bool logging_active = memslot_is_logging(memslot); + bool force_pte = logging_active; long vma_pagesize, fault_granule; enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; struct kvm_pgtable *pgt; struct page *page; vm_flags_t vm_flags; - enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED; + enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_MEMABORT_FLAGS; if (fault_is_perm) fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu); write_fault = kvm_is_write_fault(vcpu); exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); - VM_BUG_ON(write_fault && exec_fault); - - if (fault_is_perm && !write_fault && !exec_fault) { - kvm_err("Unexpected L2 read permission error\n"); - return -EFAULT; - } - - if (!is_protected_kvm_enabled()) - memcache = &vcpu->arch.mmu_page_cache; - else - memcache = &vcpu->arch.pkvm_memcache; + VM_WARN_ON_ONCE(write_fault && exec_fault); /* * Permission faults just need to update the existing leaf entry, @@ -1524,17 +1634,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, * only exception to this is when dirty logging is enabled at runtime * and a write fault needs to collapse a block entry into a table. */ - if (!fault_is_perm || (logging_active && write_fault)) { - int min_pages = kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu); - - if (!is_protected_kvm_enabled()) - ret = kvm_mmu_topup_memory_cache(memcache, min_pages); - else - ret = topup_hyp_memcache(memcache, min_pages); - - if (ret) - return ret; - } + topup_memcache = !fault_is_perm || (logging_active && write_fault); + ret = prepare_mmu_memcache(vcpu, topup_memcache, &memcache); + if (ret) + return ret; /* * Let's check if we will get back a huge page backed by hugetlbfs, or @@ -1548,16 +1651,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, return -EFAULT; } - /* - * logging_active is guaranteed to never be true for VM_PFNMAP - * memslots. - */ - if (logging_active) { - force_pte = true; + if (force_pte) vma_shift = PAGE_SHIFT; - } else { + else vma_shift = get_vma_page_shift(vma, hva); - } switch (vma_shift) { #ifndef __PAGETABLE_PMD_FOLDED @@ -1609,7 +1706,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, max_map_size = PAGE_SIZE; force_pte = (max_map_size == PAGE_SIZE); - vma_pagesize = min(vma_pagesize, (long)max_map_size); + vma_pagesize = min_t(long, vma_pagesize, max_map_size); } /* @@ -1642,7 +1739,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs * with the smp_wmb() in kvm_mmu_invalidate_end(). */ - mmu_seq = vcpu->kvm->mmu_invalidate_seq; + mmu_seq = kvm->mmu_invalidate_seq; mmap_read_unlock(current->mm); pfn = __kvm_faultin_pfn(memslot, gfn, write_fault ? FOLL_WRITE : 0, @@ -1698,24 +1795,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (exec_fault && s2_force_noncacheable) return -ENOEXEC; - /* - * Potentially reduce shadow S2 permissions to match the guest's own - * S2. For exec faults, we'd only reach this point if the guest - * actually allowed it (see kvm_s2_handle_perm_fault). - * - * Also encode the level of the original translation in the SW bits - * of the leaf entry as a proxy for the span of that translation. - * This will be retrieved on TLB invalidation from the guest and - * used to limit the invalidation scope if a TTL hint or a range - * isn't provided. - */ - if (nested) { - writable &= kvm_s2_trans_writable(nested); - if (!kvm_s2_trans_readable(nested)) - prot &= ~KVM_PGTABLE_PROT_R; - - prot |= kvm_encode_nested_level(nested); - } + if (nested) + adjust_nested_fault_perms(nested, &prot, &writable); kvm_fault_lock(kvm); pgt = vcpu->arch.hw_mmu->pgt; @@ -1981,8 +2062,15 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) goto out_unlock; } - ret = user_mem_abort(vcpu, fault_ipa, nested, memslot, hva, - esr_fsc_is_permission_fault(esr)); + VM_WARN_ON_ONCE(kvm_vcpu_trap_is_permission_fault(vcpu) && + !write_fault && !kvm_vcpu_trap_is_exec_fault(vcpu)); + + if (kvm_slot_has_gmem(memslot)) + ret = gmem_abort(vcpu, fault_ipa, nested, memslot, + esr_fsc_is_permission_fault(esr)); + else + ret = user_mem_abort(vcpu, fault_ipa, nested, memslot, hva, + esr_fsc_is_permission_fault(esr)); if (ret == 0) ret = 1; out: @@ -2214,6 +2302,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if ((new->base_gfn + new->npages) > (kvm_phys_size(&kvm->arch.mmu) >> PAGE_SHIFT)) return -EFAULT; + /* + * Only support guest_memfd backed memslots with mappable memory, since + * there aren't any CoCo VMs that support only private memory on arm64. + */ + if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new)) + return -EINVAL; + hva = new->userspace_addr; reg_end = hva + (new->npages << PAGE_SHIFT); diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 153b3e11b115..27ebcae35299 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -1172,8 +1172,9 @@ static u64 read_vncr_el2(struct kvm_vcpu *vcpu) return (u64)sign_extend64(__vcpu_sys_reg(vcpu, VNCR_EL2), 48); } -static int kvm_translate_vncr(struct kvm_vcpu *vcpu) +static int kvm_translate_vncr(struct kvm_vcpu *vcpu, bool *is_gmem) { + struct kvm_memory_slot *memslot; bool write_fault, writable; unsigned long mmu_seq; struct vncr_tlb *vt; @@ -1216,10 +1217,25 @@ static int kvm_translate_vncr(struct kvm_vcpu *vcpu) smp_rmb(); gfn = vt->wr.pa >> PAGE_SHIFT; - pfn = kvm_faultin_pfn(vcpu, gfn, write_fault, &writable, &page); - if (is_error_noslot_pfn(pfn) || (write_fault && !writable)) + memslot = gfn_to_memslot(vcpu->kvm, gfn); + if (!memslot) return -EFAULT; + *is_gmem = kvm_slot_has_gmem(memslot); + if (!*is_gmem) { + pfn = __kvm_faultin_pfn(memslot, gfn, write_fault ? FOLL_WRITE : 0, + &writable, &page); + if (is_error_noslot_pfn(pfn) || (write_fault && !writable)) + return -EFAULT; + } else { + ret = kvm_gmem_get_pfn(vcpu->kvm, memslot, gfn, &pfn, &page, NULL); + if (ret) { + kvm_prepare_memory_fault_exit(vcpu, vt->wr.pa, PAGE_SIZE, + write_fault, false, false); + return ret; + } + } + scoped_guard(write_lock, &vcpu->kvm->mmu_lock) { if (mmu_invalidate_retry(vcpu->kvm, mmu_seq)) return -EAGAIN; @@ -1292,23 +1308,36 @@ int kvm_handle_vncr_abort(struct kvm_vcpu *vcpu) if (esr_fsc_is_permission_fault(esr)) { inject_vncr_perm(vcpu); } else if (esr_fsc_is_translation_fault(esr)) { - bool valid; + bool valid, is_gmem = false; int ret; scoped_guard(read_lock, &vcpu->kvm->mmu_lock) valid = kvm_vncr_tlb_lookup(vcpu); if (!valid) - ret = kvm_translate_vncr(vcpu); + ret = kvm_translate_vncr(vcpu, &is_gmem); else ret = -EPERM; switch (ret) { case -EAGAIN: - case -ENOMEM: /* Let's try again... */ break; + case -ENOMEM: + /* + * For guest_memfd, this indicates that it failed to + * create a folio to back the memory. Inform userspace. + */ + if (is_gmem) + return 0; + /* Otherwise, let's try again... */ + break; case -EFAULT: + case -EIO: + case -EHWPOISON: + if (is_gmem) + return 0; + fallthrough; case -EINVAL: case -ENOENT: case -EACCES: diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 18a5c3119e1a..62c3e4de3303 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -145,7 +145,7 @@ KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); KVM_X86_OP_OPTIONAL(get_untagged_addr) KVM_X86_OP_OPTIONAL(alloc_apic_backing_page) KVM_X86_OP_OPTIONAL_RET0(gmem_prepare) -KVM_X86_OP_OPTIONAL_RET0(private_max_mapping_level) +KVM_X86_OP_OPTIONAL_RET0(gmem_max_mapping_level) KVM_X86_OP_OPTIONAL(gmem_invalidate) #undef KVM_X86_OP diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f19a76d3ca0e..c56cc54d682a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1922,7 +1922,7 @@ struct kvm_x86_ops { void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu); int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order); void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end); - int (*private_max_mapping_level)(struct kvm *kvm, kvm_pfn_t pfn); + int (*gmem_max_mapping_level)(struct kvm *kvm, kvm_pfn_t pfn, bool is_private); }; struct kvm_x86_nested_ops { @@ -2276,10 +2276,8 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, int tdp_max_root_level, int tdp_huge_page_level); -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem) -#else -#define kvm_arch_has_private_mem(kvm) false #endif #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 2c86673155c9..4e43923656d0 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -46,8 +46,8 @@ config KVM_X86 select HAVE_KVM_PM_NOTIFIER if PM select KVM_GENERIC_HARDWARE_ENABLING select KVM_GENERIC_PRE_FAULT_MEMORY - select KVM_GENERIC_PRIVATE_MEM if KVM_SW_PROTECTED_VM select KVM_WERROR if WERROR + select KVM_GUEST_MEMFD if X86_64 config KVM tristate "Kernel-based Virtual Machine (KVM) support" @@ -74,7 +74,7 @@ config KVM_WERROR # FRAME_WARN, i.e. KVM_WERROR=y with KASAN=y requires special tuning. # Building KVM with -Werror and KASAN is still doable via enabling # the kernel-wide WERROR=y. - depends on KVM && ((EXPERT && !KASAN) || WERROR) + depends on KVM_X86 && ((EXPERT && !KASAN) || WERROR) help Add -Werror to the build flags for KVM. @@ -83,7 +83,8 @@ config KVM_WERROR config KVM_SW_PROTECTED_VM bool "Enable support for KVM software-protected VMs" depends on EXPERT - depends on KVM && X86_64 + depends on KVM_X86 && X86_64 + select KVM_GENERIC_MEMORY_ATTRIBUTES help Enable support for KVM software-protected VMs. Currently, software- protected VMs are purely a development and testing vehicle for @@ -95,8 +96,6 @@ config KVM_SW_PROTECTED_VM config KVM_INTEL tristate "KVM for Intel (and compatible) processors support" depends on KVM && IA32_FEAT_CTL - select KVM_GENERIC_PRIVATE_MEM if INTEL_TDX_HOST - select KVM_GENERIC_MEMORY_ATTRIBUTES if INTEL_TDX_HOST help Provides support for KVM on processors equipped with Intel's VT extensions, a.k.a. Virtual Machine Extensions (VMX). @@ -135,6 +134,8 @@ config KVM_INTEL_TDX bool "Intel Trust Domain Extensions (TDX) support" default y depends on INTEL_TDX_HOST + select KVM_GENERIC_MEMORY_ATTRIBUTES + select HAVE_KVM_ARCH_GMEM_POPULATE help Provides support for launching Intel Trust Domain Extensions (TDX) confidential VMs on Intel processors. @@ -157,9 +158,10 @@ config KVM_AMD_SEV depends on KVM_AMD && X86_64 depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m) select ARCH_HAS_CC_PLATFORM - select KVM_GENERIC_PRIVATE_MEM + select KVM_GENERIC_MEMORY_ATTRIBUTES select HAVE_KVM_ARCH_GMEM_PREPARE select HAVE_KVM_ARCH_GMEM_INVALIDATE + select HAVE_KVM_ARCH_GMEM_POPULATE help Provides support for launching encrypted VMs which use Secure Encrypted Virtualization (SEV), Secure Encrypted Virtualization with @@ -169,7 +171,7 @@ config KVM_AMD_SEV config KVM_IOAPIC bool "I/O APIC, PIC, and PIT emulation" default y - depends on KVM + depends on KVM_X86 help Provides support for KVM to emulate an I/O APIC, PIC, and PIT, i.e. for full in-kernel APIC emulation. @@ -179,7 +181,7 @@ config KVM_IOAPIC config KVM_SMM bool "System Management Mode emulation" default y - depends on KVM + depends on KVM_X86 help Provides support for KVM to emulate System Management Mode (SMM) in virtual machines. This can be used by the virtual machine @@ -189,7 +191,7 @@ config KVM_SMM config KVM_HYPERV bool "Support for Microsoft Hyper-V emulation" - depends on KVM + depends on KVM_X86 default y help Provides KVM support for emulating Microsoft Hyper-V. This allows KVM @@ -203,7 +205,7 @@ config KVM_HYPERV config KVM_XEN bool "Support for Xen hypercall interface" - depends on KVM + depends on KVM_X86 help Provides KVM support for the hosting Xen HVM guests and passing Xen hypercalls to userspace. @@ -213,7 +215,7 @@ config KVM_XEN config KVM_PROVE_MMU bool "Prove KVM MMU correctness" depends on DEBUG_KERNEL - depends on KVM + depends on KVM_X86 depends on EXPERT help Enables runtime assertions in KVM's MMU that are too costly to enable @@ -228,7 +230,7 @@ config KVM_EXTERNAL_WRITE_TRACKING config KVM_MAX_NR_VCPUS int "Maximum number of vCPUs per KVM guest" - depends on KVM + depends on KVM_X86 range 1024 4096 default 4096 if MAXSMP default 1024 diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6e838cb6c9e1..56c80588efa0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3285,12 +3285,72 @@ out: return level; } -static int __kvm_mmu_max_mapping_level(struct kvm *kvm, - const struct kvm_memory_slot *slot, - gfn_t gfn, int max_level, bool is_private) +static u8 kvm_max_level_for_order(int order) +{ + BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G); + + KVM_MMU_WARN_ON(order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G) && + order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M) && + order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K)); + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G)) + return PG_LEVEL_1G; + + if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M)) + return PG_LEVEL_2M; + + return PG_LEVEL_4K; +} + +static u8 kvm_gmem_max_mapping_level(struct kvm *kvm, struct kvm_page_fault *fault, + const struct kvm_memory_slot *slot, gfn_t gfn, + bool is_private) +{ + u8 max_level, coco_level; + kvm_pfn_t pfn; + + /* For faults, use the gmem information that was resolved earlier. */ + if (fault) { + pfn = fault->pfn; + max_level = fault->max_level; + } else { + /* TODO: Call into guest_memfd once hugepages are supported. */ + WARN_ONCE(1, "Get pfn+order from guest_memfd"); + pfn = KVM_PFN_ERR_FAULT; + max_level = PG_LEVEL_4K; + } + + if (max_level == PG_LEVEL_4K) + return max_level; + + /* + * CoCo may influence the max mapping level, e.g. due to RMP or S-EPT + * restrictions. A return of '0' means "no additional restrictions", to + * allow for using an optional "ret0" static call. + */ + coco_level = kvm_x86_call(gmem_max_mapping_level)(kvm, pfn, is_private); + if (coco_level) + max_level = min(max_level, coco_level); + + return max_level; +} + +int kvm_mmu_max_mapping_level(struct kvm *kvm, struct kvm_page_fault *fault, + const struct kvm_memory_slot *slot, gfn_t gfn) { struct kvm_lpage_info *linfo; - int host_level; + int host_level, max_level; + bool is_private; + + lockdep_assert_held(&kvm->mmu_lock); + + if (fault) { + max_level = fault->max_level; + is_private = fault->is_private; + } else { + max_level = PG_LEVEL_NUM; + is_private = kvm_mem_is_private(kvm, gfn); + } max_level = min(max_level, max_huge_page_level); for ( ; max_level > PG_LEVEL_4K; max_level--) { @@ -3299,25 +3359,17 @@ static int __kvm_mmu_max_mapping_level(struct kvm *kvm, break; } - if (is_private) - return max_level; - if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; - host_level = host_pfn_mapping_level(kvm, gfn, slot); + if (is_private || kvm_memslot_is_gmem_only(slot)) + host_level = kvm_gmem_max_mapping_level(kvm, fault, slot, gfn, + is_private); + else + host_level = host_pfn_mapping_level(kvm, gfn, slot); return min(host_level, max_level); } -int kvm_mmu_max_mapping_level(struct kvm *kvm, - const struct kvm_memory_slot *slot, gfn_t gfn) -{ - bool is_private = kvm_slot_can_be_private(slot) && - kvm_mem_is_private(kvm, gfn); - - return __kvm_mmu_max_mapping_level(kvm, slot, gfn, PG_LEVEL_NUM, is_private); -} - void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { struct kvm_memory_slot *slot = fault->slot; @@ -3338,9 +3390,8 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault * Enforce the iTLB multihit workaround after capturing the requested * level, which will be used to do precise, accurate accounting. */ - fault->req_level = __kvm_mmu_max_mapping_level(vcpu->kvm, slot, - fault->gfn, fault->max_level, - fault->is_private); + fault->req_level = kvm_mmu_max_mapping_level(vcpu->kvm, fault, + fault->slot, fault->gfn); if (fault->req_level == PG_LEVEL_4K || fault->huge_page_disallowed) return; @@ -4503,42 +4554,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) vcpu->stat.pf_fixed++; } -static inline u8 kvm_max_level_for_order(int order) -{ - BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G); - - KVM_MMU_WARN_ON(order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G) && - order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M) && - order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K)); - - if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G)) - return PG_LEVEL_1G; - - if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M)) - return PG_LEVEL_2M; - - return PG_LEVEL_4K; -} - -static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, - u8 max_level, int gmem_order) -{ - u8 req_max_level; - - if (max_level == PG_LEVEL_4K) - return PG_LEVEL_4K; - - max_level = min(kvm_max_level_for_order(gmem_order), max_level); - if (max_level == PG_LEVEL_4K) - return PG_LEVEL_4K; - - req_max_level = kvm_x86_call(private_max_mapping_level)(kvm, pfn); - if (req_max_level) - max_level = min(max_level, req_max_level); - - return max_level; -} - static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, int r) { @@ -4546,12 +4561,12 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu, r == RET_PF_RETRY, fault->map_writable); } -static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, - struct kvm_page_fault *fault) +static int kvm_mmu_faultin_pfn_gmem(struct kvm_vcpu *vcpu, + struct kvm_page_fault *fault) { int max_order, r; - if (!kvm_slot_can_be_private(fault->slot)) { + if (!kvm_slot_has_gmem(fault->slot)) { kvm_mmu_prepare_memory_fault_exit(vcpu, fault); return -EFAULT; } @@ -4564,8 +4579,7 @@ static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, } fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); - fault->max_level = kvm_max_private_mapping_level(vcpu->kvm, fault->pfn, - fault->max_level, max_order); + fault->max_level = kvm_max_level_for_order(max_order); return RET_PF_CONTINUE; } @@ -4575,8 +4589,8 @@ static int __kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu, { unsigned int foll = fault->write ? FOLL_WRITE : 0; - if (fault->is_private) - return kvm_mmu_faultin_pfn_private(vcpu, fault); + if (fault->is_private || kvm_memslot_is_gmem_only(fault->slot)) + return kvm_mmu_faultin_pfn_gmem(vcpu, fault); foll |= FOLL_NOWAIT; fault->pfn = __kvm_faultin_pfn(fault->slot, fault->gfn, foll, @@ -7165,7 +7179,7 @@ restart: * mapping if the indirect sp has level = 1. */ if (sp->role.direct && - sp->role.level < kvm_mmu_max_mapping_level(kvm, slot, sp->gfn)) { + sp->role.level < kvm_mmu_max_mapping_level(kvm, NULL, slot, sp->gfn)) { kvm_zap_one_rmap_spte(kvm, rmap_head, sptep); if (kvm_available_flush_remote_tlbs_range()) diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index 65f3c89d7c5d..b776be783a2f 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -411,7 +411,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, return r; } -int kvm_mmu_max_mapping_level(struct kvm *kvm, +int kvm_mmu_max_mapping_level(struct kvm *kvm, struct kvm_page_fault *fault, const struct kvm_memory_slot *slot, gfn_t gfn); void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 7f3d7229b2c1..740cb06accdb 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1813,7 +1813,7 @@ retry: if (iter.gfn < start || iter.gfn >= end) continue; - max_mapping_level = kvm_mmu_max_mapping_level(kvm, slot, iter.gfn); + max_mapping_level = kvm_mmu_max_mapping_level(kvm, NULL, slot, iter.gfn); if (max_mapping_level < iter.level) continue; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 0635bd71c10e..5bac4d20aec0 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2361,7 +2361,7 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) mutex_lock(&kvm->slots_lock); memslot = gfn_to_memslot(kvm, params.gfn_start); - if (!kvm_slot_can_be_private(memslot)) { + if (!kvm_slot_has_gmem(memslot)) { ret = -EINVAL; goto out; } @@ -4715,7 +4715,7 @@ void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code) } slot = gfn_to_memslot(kvm, gfn); - if (!kvm_slot_can_be_private(slot)) { + if (!kvm_slot_has_gmem(slot)) { pr_warn_ratelimited("SEV: Unexpected RMP fault, non-private slot for GPA 0x%llx\n", gpa); return; @@ -4943,7 +4943,7 @@ next_pfn: } } -int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) +int sev_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private) { int level, rc; bool assigned; diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d9931c6c4bc6..8a66e2e985a4 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5180,7 +5180,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .gmem_prepare = sev_gmem_prepare, .gmem_invalidate = sev_gmem_invalidate, - .private_max_mapping_level = sev_private_max_mapping_level, + .gmem_max_mapping_level = sev_gmem_max_mapping_level, }; /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 58b9d168e0c8..70df7c6413cf 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -866,7 +866,7 @@ void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code); void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu); int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order); void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end); -int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn); +int sev_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private); struct vmcb_save_area *sev_decrypt_vmsa(struct kvm_vcpu *vcpu); void sev_free_decrypted_vmsa(struct kvm_vcpu *vcpu, struct vmcb_save_area *vmsa); #else @@ -895,7 +895,7 @@ static inline int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, in return 0; } static inline void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) {} -static inline int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) +static inline int sev_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private) { return 0; } diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c index dbab1c15b0cd..bb5f182f6788 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -831,10 +831,11 @@ static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp) return tdx_vcpu_ioctl(vcpu, argp); } -static int vt_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) +static int vt_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, + bool is_private) { if (is_td(kvm)) - return tdx_gmem_private_max_mapping_level(kvm, pfn); + return tdx_gmem_max_mapping_level(kvm, pfn, is_private); return 0; } @@ -1005,7 +1006,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { .mem_enc_ioctl = vt_op_tdx_only(mem_enc_ioctl), .vcpu_mem_enc_ioctl = vt_op_tdx_only(vcpu_mem_enc_ioctl), - .private_max_mapping_level = vt_op_tdx_only(gmem_private_max_mapping_level) + .gmem_max_mapping_level = vt_op_tdx_only(gmem_max_mapping_level) }; struct kvm_x86_init_ops vt_init_ops __initdata = { diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 66744f5768c8..ca9c8ec7dd01 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -3318,8 +3318,11 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) return ret; } -int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) +int tdx_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private) { + if (!is_private) + return 0; + return PG_LEVEL_4K; } diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h index 2b3424f638db..4c70f56c57c8 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -153,7 +153,7 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp); void tdx_flush_tlb_current(struct kvm_vcpu *vcpu); void tdx_flush_tlb_all(struct kvm_vcpu *vcpu); void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level); -int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn); +int tdx_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private); #endif #endif /* __KVM_X86_VMX_X86_OPS_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 604490b1cb19..33fba801b205 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13521,6 +13521,16 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) } EXPORT_SYMBOL_GPL(kvm_arch_no_poll); +#ifdef CONFIG_KVM_GUEST_MEMFD +/* + * KVM doesn't yet support mmap() on guest_memfd for VMs with private memory + * (the private vs. shared tracking needs to be moved into guest_memfd). + */ +bool kvm_arch_supports_gmem_mmap(struct kvm *kvm) +{ + return !kvm_arch_has_private_mem(kvm); +} + #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order) { @@ -13534,6 +13544,7 @@ void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) kvm_x86_call(gmem_invalidate)(start, end); } #endif +#endif int kvm_spec_ctrl_test_value(u64 value) { diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 15656b7fba6c..8b47891adca1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -52,9 +52,10 @@ /* * The bit 16 ~ bit 31 of kvm_userspace_memory_region::flags are internally * used in kvm, other bits are visible for userspace which are defined in - * include/linux/kvm_h. + * include/uapi/linux/kvm.h. */ -#define KVM_MEMSLOT_INVALID (1UL << 16) +#define KVM_MEMSLOT_INVALID (1UL << 16) +#define KVM_MEMSLOT_GMEM_ONLY (1UL << 17) /* * Bit 63 of the memslot generation number is an "update in-progress flag", @@ -602,7 +603,7 @@ struct kvm_memory_slot { short id; u16 as_id; -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD struct { /* * Writes protected by kvm->slots_lock. Acquiring a @@ -615,7 +616,7 @@ struct kvm_memory_slot { #endif }; -static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) +static inline bool kvm_slot_has_gmem(const struct kvm_memory_slot *slot) { return slot && (slot->flags & KVM_MEM_GUEST_MEMFD); } @@ -719,17 +720,17 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) } #endif -/* - * Arch code must define kvm_arch_has_private_mem if support for private memory - * is enabled. - */ -#if !defined(kvm_arch_has_private_mem) && !IS_ENABLED(CONFIG_KVM_PRIVATE_MEM) +#ifndef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES static inline bool kvm_arch_has_private_mem(struct kvm *kvm) { return false; } #endif +#ifdef CONFIG_KVM_GUEST_MEMFD +bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); +#endif + #ifndef kvm_arch_has_readonly_mem static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm) { @@ -860,7 +861,7 @@ struct kvm { struct notifier_block pm_notifier; #endif #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES - /* Protected by slots_locks (for writes) and RCU (for reads) */ + /* Protected by slots_lock (for writes) and RCU (for reads) */ struct xarray mem_attr_array; #endif char stats_id[KVM_STATS_NAME_SIZE]; @@ -2490,6 +2491,14 @@ static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_PRIVATE; } +static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot) +{ + if (!IS_ENABLED(CONFIG_KVM_GUEST_MEMFD)) + return false; + + return slot->flags & KVM_MEMSLOT_GMEM_ONLY; +} + #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn) { @@ -2505,8 +2514,7 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) { - return IS_ENABLED(CONFIG_KVM_PRIVATE_MEM) && - kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; + return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; } #else static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) @@ -2515,7 +2523,7 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) } #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, struct page **page, int *max_order); @@ -2528,13 +2536,13 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm, KVM_BUG_ON(1, kvm); return -EIO; } -#endif /* CONFIG_KVM_PRIVATE_MEM */ +#endif /* CONFIG_KVM_GUEST_MEMFD */ #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order); #endif -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE /** * kvm_gmem_populate() - Populate/prepare a GPA range with guest data * diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index f0f0d49d2544..6efa98a57ec1 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -962,6 +962,7 @@ struct kvm_enable_cap { #define KVM_CAP_ARM_EL2_E2H0 241 #define KVM_CAP_RISCV_MP_STATE_RESET 242 #define KVM_CAP_ARM_CACHEABLE_PFNMAP_SUPPORTED 243 +#define KVM_CAP_GUEST_MEMFD_MMAP 244 struct kvm_irq_routing_irqchip { __u32 irqchip; @@ -1598,6 +1599,7 @@ struct kvm_memory_attributes { #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) #define KVM_CREATE_GUEST_MEMFD _IOWR(KVMIO, 0xd4, struct kvm_create_guest_memfd) +#define GUEST_MEMFD_FLAG_MMAP (1ULL << 0) struct kvm_create_guest_memfd { __u64 size; diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index f6fe7a07a0a2..90f03f00cb04 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -174,6 +174,7 @@ TEST_GEN_PROGS_arm64 += arch_timer TEST_GEN_PROGS_arm64 += coalesced_io_test TEST_GEN_PROGS_arm64 += dirty_log_perf_test TEST_GEN_PROGS_arm64 += get-reg-list +TEST_GEN_PROGS_arm64 += guest_memfd_test TEST_GEN_PROGS_arm64 += memslot_modification_stress_test TEST_GEN_PROGS_arm64 += memslot_perf_test TEST_GEN_PROGS_arm64 += mmu_stress_test diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index ce687f8d248f..b3ca6737f304 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -13,12 +13,16 @@ #include <linux/bitmap.h> #include <linux/falloc.h> +#include <linux/sizes.h> +#include <setjmp.h> +#include <signal.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include "kvm_util.h" #include "test_util.h" +#include "ucall_common.h" static void test_file_read_write(int fd) { @@ -34,12 +38,83 @@ static void test_file_read_write(int fd) "pwrite on a guest_mem fd should fail"); } -static void test_mmap(int fd, size_t page_size) +static void test_mmap_supported(int fd, size_t page_size, size_t total_size) +{ + const char val = 0xaa; + char *mem; + size_t i; + int ret; + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + TEST_ASSERT(mem == MAP_FAILED, "Copy-on-write not allowed by guest_memfd."); + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() for guest_memfd should succeed."); + + memset(mem, val, total_size); + for (i = 0; i < total_size; i++) + TEST_ASSERT_EQ(READ_ONCE(mem[i]), val); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, + page_size); + TEST_ASSERT(!ret, "fallocate the first page should succeed."); + + for (i = 0; i < page_size; i++) + TEST_ASSERT_EQ(READ_ONCE(mem[i]), 0x00); + for (; i < total_size; i++) + TEST_ASSERT_EQ(READ_ONCE(mem[i]), val); + + memset(mem, val, page_size); + for (i = 0; i < total_size; i++) + TEST_ASSERT_EQ(READ_ONCE(mem[i]), val); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap() should succeed."); +} + +static sigjmp_buf jmpbuf; +void fault_sigbus_handler(int signum) +{ + siglongjmp(jmpbuf, 1); +} + +static void test_fault_overflow(int fd, size_t page_size, size_t total_size) +{ + struct sigaction sa_old, sa_new = { + .sa_handler = fault_sigbus_handler, + }; + size_t map_size = total_size * 4; + const char val = 0xaa; + char *mem; + size_t i; + int ret; + + mem = mmap(NULL, map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() for guest_memfd should succeed."); + + sigaction(SIGBUS, &sa_new, &sa_old); + if (sigsetjmp(jmpbuf, 1) == 0) { + memset(mem, 0xaa, map_size); + TEST_ASSERT(false, "memset() should have triggered SIGBUS."); + } + sigaction(SIGBUS, &sa_old, NULL); + + for (i = 0; i < total_size; i++) + TEST_ASSERT_EQ(READ_ONCE(mem[i]), val); + + ret = munmap(mem, map_size); + TEST_ASSERT(!ret, "munmap() should succeed."); +} + +static void test_mmap_not_supported(int fd, size_t page_size, size_t total_size) { char *mem; mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); TEST_ASSERT_EQ(mem, MAP_FAILED); + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT_EQ(mem, MAP_FAILED); } static void test_file_size(int fd, size_t page_size, size_t total_size) @@ -120,80 +195,187 @@ static void test_invalid_punch_hole(int fd, size_t page_size, size_t total_size) } } -static void test_create_guest_memfd_invalid(struct kvm_vm *vm) +static void test_create_guest_memfd_invalid_sizes(struct kvm_vm *vm, + uint64_t guest_memfd_flags, + size_t page_size) { - size_t page_size = getpagesize(); - uint64_t flag; size_t size; int fd; for (size = 1; size < page_size; size++) { - fd = __vm_create_guest_memfd(vm, size, 0); - TEST_ASSERT(fd == -1 && errno == EINVAL, + fd = __vm_create_guest_memfd(vm, size, guest_memfd_flags); + TEST_ASSERT(fd < 0 && errno == EINVAL, "guest_memfd() with non-page-aligned page size '0x%lx' should fail with EINVAL", size); } - - for (flag = BIT(0); flag; flag <<= 1) { - fd = __vm_create_guest_memfd(vm, page_size, flag); - TEST_ASSERT(fd == -1 && errno == EINVAL, - "guest_memfd() with flag '0x%lx' should fail with EINVAL", - flag); - } } static void test_create_guest_memfd_multiple(struct kvm_vm *vm) { int fd1, fd2, ret; struct stat st1, st2; + size_t page_size = getpagesize(); - fd1 = __vm_create_guest_memfd(vm, 4096, 0); + fd1 = __vm_create_guest_memfd(vm, page_size, 0); TEST_ASSERT(fd1 != -1, "memfd creation should succeed"); ret = fstat(fd1, &st1); TEST_ASSERT(ret != -1, "memfd fstat should succeed"); - TEST_ASSERT(st1.st_size == 4096, "memfd st_size should match requested size"); + TEST_ASSERT(st1.st_size == page_size, "memfd st_size should match requested size"); - fd2 = __vm_create_guest_memfd(vm, 8192, 0); + fd2 = __vm_create_guest_memfd(vm, page_size * 2, 0); TEST_ASSERT(fd2 != -1, "memfd creation should succeed"); ret = fstat(fd2, &st2); TEST_ASSERT(ret != -1, "memfd fstat should succeed"); - TEST_ASSERT(st2.st_size == 8192, "second memfd st_size should match requested size"); + TEST_ASSERT(st2.st_size == page_size * 2, "second memfd st_size should match requested size"); ret = fstat(fd1, &st1); TEST_ASSERT(ret != -1, "memfd fstat should succeed"); - TEST_ASSERT(st1.st_size == 4096, "first memfd st_size should still match requested size"); + TEST_ASSERT(st1.st_size == page_size, "first memfd st_size should still match requested size"); TEST_ASSERT(st1.st_ino != st2.st_ino, "different memfd should have different inode numbers"); close(fd2); close(fd1); } -int main(int argc, char *argv[]) +static void test_guest_memfd_flags(struct kvm_vm *vm, uint64_t valid_flags) { - size_t page_size; - size_t total_size; + size_t page_size = getpagesize(); + uint64_t flag; int fd; - struct kvm_vm *vm; - TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD)); + for (flag = BIT(0); flag; flag <<= 1) { + fd = __vm_create_guest_memfd(vm, page_size, flag); + if (flag & valid_flags) { + TEST_ASSERT(fd >= 0, + "guest_memfd() with flag '0x%lx' should succeed", + flag); + close(fd); + } else { + TEST_ASSERT(fd < 0 && errno == EINVAL, + "guest_memfd() with flag '0x%lx' should fail with EINVAL", + flag); + } + } +} + +static void test_guest_memfd(unsigned long vm_type) +{ + uint64_t flags = 0; + struct kvm_vm *vm; + size_t total_size; + size_t page_size; + int fd; page_size = getpagesize(); total_size = page_size * 4; - vm = vm_create_barebones(); + vm = vm_create_barebones_type(vm_type); + + if (vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP)) + flags |= GUEST_MEMFD_FLAG_MMAP; - test_create_guest_memfd_invalid(vm); test_create_guest_memfd_multiple(vm); + test_create_guest_memfd_invalid_sizes(vm, flags, page_size); - fd = vm_create_guest_memfd(vm, total_size, 0); + fd = vm_create_guest_memfd(vm, total_size, flags); test_file_read_write(fd); - test_mmap(fd, page_size); + + if (flags & GUEST_MEMFD_FLAG_MMAP) { + test_mmap_supported(fd, page_size, total_size); + test_fault_overflow(fd, page_size, total_size); + } else { + test_mmap_not_supported(fd, page_size, total_size); + } + test_file_size(fd, page_size, total_size); test_fallocate(fd, page_size, total_size); test_invalid_punch_hole(fd, page_size, total_size); + test_guest_memfd_flags(vm, flags); + close(fd); + kvm_vm_free(vm); +} + +static void guest_code(uint8_t *mem, uint64_t size) +{ + size_t i; + + for (i = 0; i < size; i++) + __GUEST_ASSERT(mem[i] == 0xaa, + "Guest expected 0xaa at offset %lu, got 0x%x", i, mem[i]); + + memset(mem, 0xff, size); + GUEST_DONE(); +} + +static void test_guest_memfd_guest(void) +{ + /* + * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back + * the guest's code, stack, and page tables, and low memory contains + * the PCI hole and other MMIO regions that need to be avoided. + */ + const uint64_t gpa = SZ_4G; + const int slot = 1; + + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + uint8_t *mem; + size_t size; + int fd, i; + + if (!kvm_has_cap(KVM_CAP_GUEST_MEMFD_MMAP)) + return; + + vm = __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, guest_code); + + TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP), + "Default VM type should always support guest_memfd mmap()"); + + size = vm->page_size; + fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP); + vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0); + + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); + memset(mem, 0xaa, size); + munmap(mem, size); + + virt_pg_map(vm, gpa, gpa); + vcpu_args_set(vcpu, 2, gpa, size); + vcpu_run(vcpu); + + TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE); + + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); + for (i = 0; i < size; i++) + TEST_ASSERT_EQ(mem[i], 0xff); + + close(fd); + kvm_vm_free(vm); +} + +int main(int argc, char *argv[]) +{ + unsigned long vm_types, vm_type; + + TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD)); + + /* + * Not all architectures support KVM_CAP_VM_TYPES. However, those that + * support guest_memfd have that support for the default VM type. + */ + vm_types = kvm_check_cap(KVM_CAP_VM_TYPES); + if (!vm_types) + vm_types = BIT(VM_TYPE_DEFAULT); + + for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types)) + test_guest_memfd(vm_type); + + test_guest_memfd_guest(); } diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 727b542074e7..1b7d5be0b6c4 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -112,19 +112,18 @@ config KVM_GENERIC_MEMORY_ATTRIBUTES depends on KVM_GENERIC_MMU_NOTIFIER bool -config KVM_PRIVATE_MEM +config KVM_GUEST_MEMFD select XARRAY_MULTI bool -config KVM_GENERIC_PRIVATE_MEM - select KVM_GENERIC_MEMORY_ATTRIBUTES - select KVM_PRIVATE_MEM - bool - config HAVE_KVM_ARCH_GMEM_PREPARE bool - depends on KVM_PRIVATE_MEM + depends on KVM_GUEST_MEMFD config HAVE_KVM_ARCH_GMEM_INVALIDATE bool - depends on KVM_PRIVATE_MEM + depends on KVM_GUEST_MEMFD + +config HAVE_KVM_ARCH_GMEM_POPULATE + bool + depends on KVM_GUEST_MEMFD diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm index 724c89af78af..d047d4cf58c9 100644 --- a/virt/kvm/Makefile.kvm +++ b/virt/kvm/Makefile.kvm @@ -12,4 +12,4 @@ kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o kvm-$(CONFIG_HAVE_KVM_DIRTY_RING) += $(KVM)/dirty_ring.o kvm-$(CONFIG_HAVE_KVM_PFNCACHE) += $(KVM)/pfncache.o -kvm-$(CONFIG_KVM_PRIVATE_MEM) += $(KVM)/guest_memfd.o +kvm-$(CONFIG_KVM_GUEST_MEMFD) += $(KVM)/guest_memfd.o diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 7d85cc33c0bb..08a6bc7d25b6 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -312,7 +312,74 @@ static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn) return gfn - slot->base_gfn + slot->gmem.pgoff; } +static bool kvm_gmem_supports_mmap(struct inode *inode) +{ + const u64 flags = (u64)inode->i_private; + + return flags & GUEST_MEMFD_FLAG_MMAP; +} + +static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf) +{ + struct inode *inode = file_inode(vmf->vma->vm_file); + struct folio *folio; + vm_fault_t ret = VM_FAULT_LOCKED; + + if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) + return VM_FAULT_SIGBUS; + + folio = kvm_gmem_get_folio(inode, vmf->pgoff); + if (IS_ERR(folio)) { + int err = PTR_ERR(folio); + + if (err == -EAGAIN) + return VM_FAULT_RETRY; + + return vmf_error(err); + } + + if (WARN_ON_ONCE(folio_test_large(folio))) { + ret = VM_FAULT_SIGBUS; + goto out_folio; + } + + if (!folio_test_uptodate(folio)) { + clear_highpage(folio_page(folio, 0)); + kvm_gmem_mark_prepared(folio); + } + + vmf->page = folio_file_page(folio, vmf->pgoff); + +out_folio: + if (ret != VM_FAULT_LOCKED) { + folio_unlock(folio); + folio_put(folio); + } + + return ret; +} + +static const struct vm_operations_struct kvm_gmem_vm_ops = { + .fault = kvm_gmem_fault_user_mapping, +}; + +static int kvm_gmem_mmap(struct file *file, struct vm_area_struct *vma) +{ + if (!kvm_gmem_supports_mmap(file_inode(file))) + return -ENODEV; + + if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) != + (VM_SHARED | VM_MAYSHARE)) { + return -EINVAL; + } + + vma->vm_ops = &kvm_gmem_vm_ops; + + return 0; +} + static struct file_operations kvm_gmem_fops = { + .mmap = kvm_gmem_mmap, .open = generic_file_open, .release = kvm_gmem_release, .fallocate = kvm_gmem_fallocate, @@ -391,6 +458,11 @@ static const struct inode_operations kvm_gmem_iops = { .setattr = kvm_gmem_setattr, }; +bool __weak kvm_arch_supports_gmem_mmap(struct kvm *kvm) +{ + return true; +} + static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) { const char *anon_name = "[kvm-gmem]"; @@ -452,6 +524,9 @@ int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args) u64 flags = args->flags; u64 valid_flags = 0; + if (kvm_arch_supports_gmem_mmap(kvm)) + valid_flags |= GUEST_MEMFD_FLAG_MMAP; + if (flags & ~valid_flags) return -EINVAL; @@ -508,6 +583,8 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, */ WRITE_ONCE(slot->gmem.file, file); slot->gmem.pgoff = start; + if (kvm_gmem_supports_mmap(inode)) + slot->flags |= KVM_MEMSLOT_GMEM_ONLY; xa_store_range(&gmem->bindings, start, end - 1, slot, GFP_KERNEL); filemap_invalidate_unlock(inode->i_mapping); @@ -627,7 +704,7 @@ out: } EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn); -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages, kvm_gmem_populate_cb post_populate, void *opaque) { @@ -643,7 +720,7 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long return -EINVAL; slot = gfn_to_memslot(kvm, start_gfn); - if (!kvm_slot_can_be_private(slot)) + if (!kvm_slot_has_gmem(slot)) return -EINVAL; file = kvm_gmem_get_file(slot); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6c07dd423458..18f29ef93543 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -331,7 +331,7 @@ void kvm_flush_remote_tlbs_memslot(struct kvm *kvm, * All current use cases for flushing the TLBs for a specific memslot * are related to dirty logging, and many do the TLB flush out of * mmu_lock. The interaction between the various operations on memslot - * must be serialized by slots_locks to ensure the TLB flush from one + * must be serialized by slots_lock to ensure the TLB flush from one * operation is observed by any other operation on the same memslot. */ lockdep_assert_held(&kvm->slots_lock); @@ -1588,7 +1588,7 @@ static int check_memory_region_flags(struct kvm *kvm, { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; - if (kvm_arch_has_private_mem(kvm)) + if (IS_ENABLED(CONFIG_KVM_GUEST_MEMFD)) valid_flags |= KVM_MEM_GUEST_MEMFD; /* Dirty logging private memory is not currently supported. */ @@ -4915,9 +4915,11 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) case KVM_CAP_MEMORY_ATTRIBUTES: return kvm_supported_mem_attributes(kvm); #endif -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD case KVM_CAP_GUEST_MEMFD: - return !kvm || kvm_arch_has_private_mem(kvm); + return 1; + case KVM_CAP_GUEST_MEMFD_MMAP: + return !kvm || kvm_arch_supports_gmem_mmap(kvm); #endif default: break; @@ -5352,7 +5354,7 @@ static long kvm_vm_ioctl(struct file *filp, case KVM_GET_STATS_FD: r = kvm_vm_ioctl_get_stats_fd(kvm); break; -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD case KVM_CREATE_GUEST_MEMFD: { struct kvm_create_guest_memfd guest_memfd; diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h index acef3f5c582a..31defb08ccba 100644 --- a/virt/kvm/kvm_mm.h +++ b/virt/kvm/kvm_mm.h @@ -67,7 +67,7 @@ static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, } #endif /* HAVE_KVM_PFNCACHE */ -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD void kvm_gmem_init(struct module *module); int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args); int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, @@ -91,6 +91,6 @@ static inline void kvm_gmem_unbind(struct kvm_memory_slot *slot) { WARN_ON_ONCE(1); } -#endif /* CONFIG_KVM_PRIVATE_MEM */ +#endif /* CONFIG_KVM_GUEST_MEMFD */ #endif /* __KVM_MM_H__ */ |