On 12/12/18 18:57, Vitaly Kuznetsov wrote: > The TLFS structures are used for hypervisor-guest communication and must > exactly meet the specification. > > Compilers can add alignment padding to structures or reorder struct members > for randomization and optimization, which would break the hypervisor ABI. > > Mark the structures as packed to prevent this. 'struct hv_vp_assist_page' > and 'struct hv_enlightened_vmcs' need to be properly padded to support the > change. > > Suggested-by: Nadav Amit <[email protected]> > Signed-off-by: Vitaly Kuznetsov <[email protected]> > Acked-by: Thomas Gleixner <[email protected]> > Acked-by: Nadav Amit <[email protected]> > Reviewed-by: Michael Kelley <[email protected]> > --- > - Changes since v3: > - Properly pad 'struct hv_vp_assist_page' and 'struct hv_enlightened_vmcs'. > - Add Michael's Reviewed-by tag. > > - This is a follow-up to my "[PATCH v2 0/4] x86/kvm/hyper-v: Implement > Direct Mode for synthetic timers" series, as suggested by Thomas I'm > routing it to KVM tree to avoid merge conflicts. > --- > arch/x86/include/asm/hyperv-tlfs.h | 57 ++++++++++++++++-------------- > 1 file changed, 30 insertions(+), 27 deletions(-) > > diff --git a/arch/x86/include/asm/hyperv-tlfs.h > b/arch/x86/include/asm/hyperv-tlfs.h > index ebfed56976d2..64d2b1914d37 100644 > --- a/arch/x86/include/asm/hyperv-tlfs.h > +++ b/arch/x86/include/asm/hyperv-tlfs.h > @@ -271,7 +271,7 @@ union hv_x64_msr_hypercall_contents { > u64 enable:1; > u64 reserved:11; > u64 guest_physical_address:52; > - }; > + } __packed; > }; > > /* > @@ -283,7 +283,7 @@ struct ms_hyperv_tsc_page { > volatile u64 tsc_scale; > volatile s64 tsc_offset; > u64 reserved2[509]; > -}; > +} __packed; > > /* > * The guest OS needs to register the guest ID with the hypervisor. > @@ -324,7 +324,7 @@ struct hv_reenlightenment_control { > __u64 enabled:1; > __u64 reserved2:15; > __u64 target_vp:32; > -}; > +} __packed; > > #define HV_X64_MSR_TSC_EMULATION_CONTROL 0x40000107 > #define HV_X64_MSR_TSC_EMULATION_STATUS 0x40000108 > @@ -332,12 +332,12 @@ struct hv_reenlightenment_control { > struct hv_tsc_emulation_control { > __u64 enabled:1; > __u64 reserved:63; > -}; > +} __packed; > > struct hv_tsc_emulation_status { > __u64 inprogress:1; > __u64 reserved:63; > -}; > +} __packed; > > #define HV_X64_MSR_HYPERCALL_ENABLE 0x00000001 > #define HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT 12 > @@ -409,7 +409,7 @@ typedef struct _HV_REFERENCE_TSC_PAGE { > __u32 res1; > __u64 tsc_scale; > __s64 tsc_offset; > -} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; > +} __packed HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; > > /* Define the number of synthetic interrupt sources. */ > #define HV_SYNIC_SINT_COUNT (16) > @@ -466,7 +466,7 @@ union hv_message_flags { > struct { > __u8 msg_pending:1; > __u8 reserved:7; > - }; > + } __packed; > }; > > /* Define port identifier type. */ > @@ -475,7 +475,7 @@ union hv_port_id { > struct { > __u32 id:24; > __u32 reserved:8; > - } u; > + } __packed u; > }; > > /* Define synthetic interrupt controller message header. */ > @@ -488,7 +488,7 @@ struct hv_message_header { > __u64 sender; > union hv_port_id port; > }; > -}; > +} __packed; > > /* Define synthetic interrupt controller message format. */ > struct hv_message { > @@ -496,12 +496,12 @@ struct hv_message { > union { > __u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT]; > } u; > -}; > +} __packed; > > /* Define the synthetic interrupt message page layout. */ > struct hv_message_page { > struct hv_message sint_message[HV_SYNIC_SINT_COUNT]; > -}; > +} __packed; > > /* Define timer message payload structure. */ > struct hv_timer_message_payload { > @@ -509,7 +509,7 @@ struct hv_timer_message_payload { > __u32 reserved; > __u64 expiration_time; /* When the timer expired */ > __u64 delivery_time; /* When the message was delivered */ > -}; > +} __packed; > > /* Define virtual processor assist page structure. */ > struct hv_vp_assist_page { > @@ -518,8 +518,9 @@ struct hv_vp_assist_page { > __u64 vtl_control[2]; > __u64 nested_enlightenments_control[2]; > __u32 enlighten_vmentry; > + __u32 padding; > __u64 current_nested_vmcs; > -}; > +} __packed; > > struct hv_enlightened_vmcs { > u32 revision_id; > @@ -533,6 +534,8 @@ struct hv_enlightened_vmcs { > u16 host_gs_selector; > u16 host_tr_selector; > > + u16 padding16_1; > + > u64 host_ia32_pat; > u64 host_ia32_efer; > > @@ -651,7 +654,7 @@ struct hv_enlightened_vmcs { > u64 ept_pointer; > > u16 virtual_processor_id; > - u16 padding16[3]; > + u16 padding16_2[3]; > > u64 padding64_2[5]; > u64 guest_physical_address; > @@ -693,7 +696,7 @@ struct hv_enlightened_vmcs { > u32 nested_flush_hypercall:1; > u32 msr_bitmap:1; > u32 reserved:30; > - } hv_enlightenments_control; > + } __packed hv_enlightenments_control; > u32 hv_vp_id; > > u64 hv_vm_id; > @@ -703,7 +706,7 @@ struct hv_enlightened_vmcs { > u64 padding64_5[7]; > u64 xss_exit_bitmap; > u64 padding64_6[7]; > -}; > +} __packed; > > #define HV_VMX_ENLIGHTENED_CLEAN_FIELD_NONE 0 > #define HV_VMX_ENLIGHTENED_CLEAN_FIELD_IO_BITMAP BIT(0) > @@ -744,7 +747,7 @@ union hv_stimer_config { > u64 reserved_z0:3; > u64 sintx:4; > u64 reserved_z1:44; > - }; > + } __packed; > }; > > > @@ -759,7 +762,7 @@ union hv_synic_scontrol { > struct { > u64 enable:1; > u64 reserved:63; > - }; > + } __packed; > }; > > /* Define synthetic interrupt source. */ > @@ -771,7 +774,7 @@ union hv_synic_sint { > u64 masked:1; > u64 auto_eoi:1; > u64 reserved2:46; > - }; > + } __packed; > }; > > /* Define the format of the SIMP register */ > @@ -781,7 +784,7 @@ union hv_synic_simp { > u64 simp_enabled:1; > u64 preserved:11; > u64 base_simp_gpa:52; > - }; > + } __packed; > }; > > /* Define the format of the SIEFP register */ > @@ -791,34 +794,34 @@ union hv_synic_siefp { > u64 siefp_enabled:1; > u64 preserved:11; > u64 base_siefp_gpa:52; > - }; > + } __packed; > }; > > struct hv_vpset { > u64 format; > u64 valid_bank_mask; > u64 bank_contents[]; > -}; > +} __packed; > > /* HvCallSendSyntheticClusterIpi hypercall */ > struct hv_send_ipi { > u32 vector; > u32 reserved; > u64 cpu_mask; > -}; > +} __packed; > > /* HvCallSendSyntheticClusterIpiEx hypercall */ > struct hv_send_ipi_ex { > u32 vector; > u32 reserved; > struct hv_vpset vp_set; > -}; > +} __packed; > > /* HvFlushGuestPhysicalAddressSpace hypercalls */ > struct hv_guest_mapping_flush { > u64 address_space; > u64 flags; > -}; > +} __packed; > > /* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */ > struct hv_tlb_flush { > @@ -826,7 +829,7 @@ struct hv_tlb_flush { > u64 flags; > u64 processor_mask; > u64 gva_list[]; > -}; > +} __packed; > > /* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */ > struct hv_tlb_flush_ex { > @@ -834,6 +837,6 @@ struct hv_tlb_flush_ex { > u64 flags; > struct hv_vpset hv_vp_set; > u64 gva_list[]; > -}; > +} __packed; > > #endif >
Queued, thanks. I squashed the SynIC parts into "x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h" and kept the rest separate. Paolo
