| Message ID | 20240417153450.3608097-7-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Guest Memory Pre-Population API | expand |
On Wed, Apr 17, 2024 at 11:34:49AM -0400, Paolo Bonzini <pbonzini@redhat.com> wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Wire KVM_MAP_MEMORY ioctl to kvm_mmu_map_tdp_page() to populate guest > memory. When KVM_CREATE_VCPU creates vCPU, it initializes the x86 > KVM MMU part by kvm_mmu_create() and kvm_init_mmu(). vCPU is ready to > invoke the KVM page fault handler. As a record for the past discussion and to address Rick comment at https://lore.kernel.org/all/75b213fd73fcb5872703f89a9c6bb67ea91e3bd7.camel@intel.com/ The current implementation supports TDP only because the population with GVA is moot based on the thread [1]. If necessary, this restriction can be relaxed in future. [1] https://lore.kernel.org/all/116179545fafbf39ed01e1f0f5ac76e0467fc09a.camel@intel.com/ > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > Message-ID: <7138a3bc00ea8d3cbe0e59df15f8c22027005b59.1712785629.git.isaku.yamahata@intel.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/x86.c | 43 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 7632fe6e4db9..e58360d368ec 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -44,6 +44,7 @@ config KVM > select KVM_VFIO > select HAVE_KVM_PM_NOTIFIER if PM > select KVM_GENERIC_HARDWARE_ENABLING > + select KVM_GENERIC_MAP_MEMORY > help > Support hosting fully virtualized guest machines using hardware > virtualization extensions. You will need a fairly recent > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 83b8260443a3..f84c75c2a47f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4715,6 +4715,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_MEMORY_FAULT_INFO: > r = 1; > break; > + case KVM_CAP_MAP_MEMORY: > + r = tdp_enabled; > + break; > case KVM_CAP_EXIT_HYPERCALL: > r = KVM_EXIT_HYPERCALL_VALID_MASK; > break; > @@ -5867,6 +5870,46 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, > } > } > > +int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu, > + struct kvm_map_memory *mapping) > +{ > + u64 mapped, end, error_code = 0; > + u8 level = PG_LEVEL_4K; > + int r; > + > + /* > + * Shadow paging uses GVA for kvm page fault. The first implementation > + * supports GPA only to avoid confusion. > + */ > + if (!tdp_enabled) > + return -EOPNOTSUPP; > + > + /* > + * reload is efficient when called repeatedly, so we can do it on > + * every iteration. > + */ > + kvm_mmu_reload(vcpu); > + > + if (kvm_arch_has_private_mem(vcpu->kvm) && > + kvm_mem_is_private(vcpu->kvm, gpa_to_gfn(mapping->base_address))) > + error_code |= PFERR_PRIVATE_ACCESS; > + > + r = kvm_tdp_map_page(vcpu, mapping->base_address, error_code, &level); > + if (r) > + return r; > + > + /* > + * level can be more than the alignment of mapping->base_address if > + * the mapping can use a huge page. > + */ > + end = (mapping->base_address & KVM_HPAGE_MASK(level)) + > + KVM_HPAGE_SIZE(level); end = ALIGN(mapping->base_address, KVM_HPAGE_SIZE(level)); ALIGN() simplifies this as Chao pointed out. https://lore.kernel.org/all/Zh94V8ochIXEkO17@chao-email/ > + mapped = min(mapping->size, end - mapping->base_address); > + mapping->size -= mapped; > + mapping->base_address += mapped; > + return r; > +} > + > long kvm_arch_vcpu_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg) > { > -- > 2.43.0 > > >
On Wed, Apr 17, 2024, Paolo Bonzini wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Wire KVM_MAP_MEMORY ioctl to kvm_mmu_map_tdp_page() to populate guest > memory. When KVM_CREATE_VCPU creates vCPU, it initializes the x86 > KVM MMU part by kvm_mmu_create() and kvm_init_mmu(). vCPU is ready to > invoke the KVM page fault handler. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > Message-ID: <7138a3bc00ea8d3cbe0e59df15f8c22027005b59.1712785629.git.isaku.yamahata@intel.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/x86.c | 43 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 7632fe6e4db9..e58360d368ec 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -44,6 +44,7 @@ config KVM > select KVM_VFIO > select HAVE_KVM_PM_NOTIFIER if PM > select KVM_GENERIC_HARDWARE_ENABLING > + select KVM_GENERIC_MAP_MEMORY > help > Support hosting fully virtualized guest machines using hardware > virtualization extensions. You will need a fairly recent > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 83b8260443a3..f84c75c2a47f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4715,6 +4715,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_MEMORY_FAULT_INFO: > r = 1; > break; > + case KVM_CAP_MAP_MEMORY: > + r = tdp_enabled; > + break; > case KVM_CAP_EXIT_HYPERCALL: > r = KVM_EXIT_HYPERCALL_VALID_MASK; > break; > @@ -5867,6 +5870,46 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, > } > } > > +int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu, > + struct kvm_map_memory *mapping) > +{ > + u64 mapped, end, error_code = 0; Maybe add PFERR_GUEST_FINAL_MASK to the error code? KVM doesn't currently consume that except in svm_check_emulate_instruction(), which isn't reachable, but it seems logical? > + u8 level = PG_LEVEL_4K; > + int r; > + > + /* > + * Shadow paging uses GVA for kvm page fault. The first implementation > + * supports GPA only to avoid confusion. > + */ > + if (!tdp_enabled) Eh, I'd omit this explicit check since kvm_tdp_map_page() has a more complete check. Actually, why is this a separate function and a separate patch? Just implement kvm_arch_vcpu_map_memory() in mmu.c, in a single patch, e.g. int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu, struct kvm_map_memory *mapping) { u64 mapped, end, error_code = 0; u8 level = PG_LEVEL_4K; int r; if (vcpu->arch.mmu->page_fault != kvm_tdp_page_fault) return -EOPNOTSUPP; kvm_mmu_reload(vcpu); if (kvm_arch_has_private_mem(vcpu->kvm) && kvm_mem_is_private(vcpu->kvm, gpa_to_gfn(mapping->base_address))) error_code |= PFERR_PRIVATE_ACCESS; r = __kvm_mmu_do_page_fault(vcpu, mapping->gpa, error_code, true, NULL, &level); if (r < 0) return r; switch (r) { case RET_PF_RETRY: return -EAGAIN; case RET_PF_FIXED: case RET_PF_SPURIOUS: break; case RET_PF_EMULATE: return -EBUSY; case RET_PF_CONTINUE: case RET_PF_INVALID: default: WARN_ON_ONCE(r); return -EIO; } /* * Adjust the GPA down when accounting for the page size, as KVM could * have created a hugepage that covers @gpa, but doesn't start at @gpa. */ end = (mapping->gpa & KVM_HPAGE_MASK(level)) + KVM_HPAGE_SIZE(level); return min(mapping->size, end - mapping->gpa); }
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 7632fe6e4db9..e58360d368ec 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -44,6 +44,7 @@ config KVM select KVM_VFIO select HAVE_KVM_PM_NOTIFIER if PM select KVM_GENERIC_HARDWARE_ENABLING + select KVM_GENERIC_MAP_MEMORY help Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 83b8260443a3..f84c75c2a47f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4715,6 +4715,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_MEMORY_FAULT_INFO: r = 1; break; + case KVM_CAP_MAP_MEMORY: + r = tdp_enabled; + break; case KVM_CAP_EXIT_HYPERCALL: r = KVM_EXIT_HYPERCALL_VALID_MASK; break; @@ -5867,6 +5870,46 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, } } +int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu, + struct kvm_map_memory *mapping) +{ + u64 mapped, end, error_code = 0; + u8 level = PG_LEVEL_4K; + int r; + + /* + * Shadow paging uses GVA for kvm page fault. The first implementation + * supports GPA only to avoid confusion. + */ + if (!tdp_enabled) + return -EOPNOTSUPP; + + /* + * reload is efficient when called repeatedly, so we can do it on + * every iteration. + */ + kvm_mmu_reload(vcpu); + + if (kvm_arch_has_private_mem(vcpu->kvm) && + kvm_mem_is_private(vcpu->kvm, gpa_to_gfn(mapping->base_address))) + error_code |= PFERR_PRIVATE_ACCESS; + + r = kvm_tdp_map_page(vcpu, mapping->base_address, error_code, &level); + if (r) + return r; + + /* + * level can be more than the alignment of mapping->base_address if + * the mapping can use a huge page. + */ + end = (mapping->base_address & KVM_HPAGE_MASK(level)) + + KVM_HPAGE_SIZE(level); + mapped = min(mapping->size, end - mapping->base_address); + mapping->size -= mapped; + mapping->base_address += mapped; + return r; +} + long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) {