On 07/07/2017 01:03, Bandan Das wrote: > When L2 uses vmfunc, L0 utilizes the associated vmexit to > emulate a switching of the ept pointer by reloading the > guest MMU. > > Signed-off-by: Paolo Bonzini <[email protected]> > Signed-off-by: Bandan Das <[email protected]> > --- > arch/x86/include/asm/vmx.h | 6 +++++ > arch/x86/kvm/vmx.c | 55 > +++++++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 58 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h > index da5375e..5f63a2e 100644 > --- a/arch/x86/include/asm/vmx.h > +++ b/arch/x86/include/asm/vmx.h > @@ -115,6 +115,10 @@ > #define VMX_MISC_SAVE_EFER_LMA 0x00000020 > #define VMX_MISC_ACTIVITY_HLT 0x00000040 > > +/* VMFUNC functions */ > +#define VMX_VMFUNC_EPTP_SWITCHING 0x00000001 > +#define VMFUNC_EPTP_ENTRIES 512 > + > static inline u32 vmx_basic_vmcs_revision_id(u64 vmx_basic) > { > return vmx_basic & GENMASK_ULL(30, 0); > @@ -200,6 +204,8 @@ enum vmcs_field { > EOI_EXIT_BITMAP2_HIGH = 0x00002021, > EOI_EXIT_BITMAP3 = 0x00002022, > EOI_EXIT_BITMAP3_HIGH = 0x00002023, > + EPTP_LIST_ADDRESS = 0x00002024, > + EPTP_LIST_ADDRESS_HIGH = 0x00002025, > VMREAD_BITMAP = 0x00002026, > VMWRITE_BITMAP = 0x00002028, > XSS_EXIT_BITMAP = 0x0000202C, > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 7364678..3a4aa68 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -246,6 +246,7 @@ struct __packed vmcs12 { > u64 eoi_exit_bitmap1; > u64 eoi_exit_bitmap2; > u64 eoi_exit_bitmap3; > + u64 eptp_list_address; > u64 xss_exit_bitmap; > u64 guest_physical_address; > u64 vmcs_link_pointer; > @@ -771,6 +772,7 @@ static const unsigned short vmcs_field_to_offset_table[] > = { > FIELD64(EOI_EXIT_BITMAP1, eoi_exit_bitmap1), > FIELD64(EOI_EXIT_BITMAP2, eoi_exit_bitmap2), > FIELD64(EOI_EXIT_BITMAP3, eoi_exit_bitmap3), > + FIELD64(EPTP_LIST_ADDRESS, eptp_list_address), > FIELD64(XSS_EXIT_BITMAP, xss_exit_bitmap), > FIELD64(GUEST_PHYSICAL_ADDRESS, guest_physical_address), > FIELD64(VMCS_LINK_POINTER, vmcs_link_pointer), > @@ -1402,6 +1404,13 @@ static inline bool nested_cpu_has_vmfunc(struct vmcs12 > *vmcs12) > return nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENABLE_VMFUNC); > } > > +static inline bool nested_cpu_has_eptp_switching(struct vmcs12 *vmcs12) > +{ > + return nested_cpu_has_vmfunc(vmcs12) && > + (vmcs12->vm_function_control & > + VMX_VMFUNC_EPTP_SWITCHING); > +} > + > static inline bool is_nmi(u32 intr_info) > { > return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK)) > @@ -2791,7 +2800,12 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx > *vmx) > if (cpu_has_vmx_vmfunc()) { > vmx->nested.nested_vmx_secondary_ctls_high |= > SECONDARY_EXEC_ENABLE_VMFUNC; > - vmx->nested.nested_vmx_vmfunc_controls = 0; > + /* > + * Advertise EPTP switching unconditionally > + * since we emulate it > + */ > + vmx->nested.nested_vmx_vmfunc_controls = > + VMX_VMFUNC_EPTP_SWITCHING; > } > > /* > @@ -7772,6 +7786,9 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu) > struct vcpu_vmx *vmx = to_vmx(vcpu); > struct vmcs12 *vmcs12; > u32 function = vcpu->arch.regs[VCPU_REGS_RAX]; > + u32 index = vcpu->arch.regs[VCPU_REGS_RCX]; > + struct page *page = NULL; > + u64 *l1_eptp_list; > > /* > * VMFUNC is only supported for nested guests, but we always enable the > @@ -7784,11 +7801,43 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu) > } > > vmcs12 = get_vmcs12(vcpu); > - if ((vmcs12->vm_function_control & (1 << function)) == 0) > + if (((vmcs12->vm_function_control & (1 << function)) == 0) || > + WARN_ON_ONCE(function)) > + goto fail; > + > + if (!nested_cpu_has_ept(vmcs12) || > + !nested_cpu_has_eptp_switching(vmcs12)) > + goto fail; > + > + if (!vmcs12->eptp_list_address || index >= VMFUNC_EPTP_ENTRIES) > + goto fail; > + > + page = nested_get_page(vcpu, vmcs12->eptp_list_address); > + if (!page) > + goto fail; > + > + l1_eptp_list = kmap(page); > + if (!l1_eptp_list[index]) > goto fail; > - WARN(1, "VMCS12 VM function control should have been zero"); > + > + /* > + * If the (L2) guest does a vmfunc to the currently > + * active ept pointer, we don't have to do anything else > + */ > + if (vmcs12->ept_pointer != l1_eptp_list[index]) { > + kvm_mmu_unload(vcpu); > + /* > + * TODO: Verify that guest ept satisfies vmentry prereqs > + */ > + vmcs12->ept_pointer = l1_eptp_list[index]; > + kvm_mmu_reload(vcpu); > + kunmap(page); > + }
Missing nested_release_page_clean, here and at the "fail" label. The TODO is a symptom of a bigger problem, so I guess it's okay for now. Paolo > + return kvm_skip_emulated_instruction(vcpu); > > fail: > + if (page) > + kunmap(page); > nested_vmx_vmexit(vcpu, vmx->exit_reason, > vmcs_read32(VM_EXIT_INTR_INFO), > vmcs_readl(EXIT_QUALIFICATION)); >
