Messages in this thread | | | Date | Wed, 17 Apr 2024 14:37:31 -0700 | Subject | Re: [PATCH 6/7] KVM: x86: Implement kvm_arch_vcpu_map_memory() | From | Sean Christopherson <> |
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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); }
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