Re: [PATCH RFC 2/7] KVM: nVMX: modify vmcs12 fields to match Hyper-V enlightened VMCS

Jim Mattson
2017-12-18T20:23:05Z

Yikes! This breaks migration to/from older versions of kvm. Will you
be submitting another change to handle dynamic conversion between
formats?

On Mon, Dec 18, 2017 at 9:17 AM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> From: Ladi Prosek <lprosek@redhat.com>
>
> Reorders existing fields and adds fields specific to Hyper-V. The layout
> now matches Hyper-V TLFS 5.0b 16.11.2 Enlightened VMCS.
>
> Fields used by KVM but missing from Hyper-V are placed in the second half
> of the VMCS page to minimize the chances they will clash with future
> enlightened VMCS versions.
>
> Signed-off-by: Ladi Prosek <lprosek@redhat.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> [Vitaly]: Update VMCS12_REVISION to some new arbitrary number.
> ---
> arch/x86/kvm/vmx.c | 321 +++++++++++++++++++++++++++++++----------------------
> 1 file changed, 187 insertions(+), 134 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 8eba631c4dbd..cd5f29a57880 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -239,159 +239,212 @@ struct __packed vmcs12 {
> u32 revision_id;
> u32 abort;
>
> + union {
> + u64 hv_vmcs[255];
> + struct {
> + u16 host_es_selector;
> + u16 host_cs_selector;
> + u16 host_ss_selector;
> + u16 host_ds_selector;
> + u16 host_fs_selector;
> + u16 host_gs_selector;
> + u16 host_tr_selector;
> +
> + u64 host_ia32_pat;
> + u64 host_ia32_efer;
> +
> + /*
> + * To allow migration of L1 (complete with its L2
> + * guests) between machines of different natural widths
> + * (32 or 64 bit), we cannot have unsigned long fields
> + * with no explicit size. We use u64 (aliased
> + * natural_width) instead. Luckily, x86 is
> + * little-endian.
> + */
> + natural_width host_cr0;
> + natural_width host_cr3;
> + natural_width host_cr4;
> +
> + natural_width host_ia32_sysenter_esp;
> + natural_width host_ia32_sysenter_eip;
> + natural_width host_rip;
> + u32 host_ia32_sysenter_cs;
> +
> + u32 pin_based_vm_exec_control;
> + u32 vm_exit_controls;
> + u32 secondary_vm_exec_control;
> +
> + u64 io_bitmap_a;
> + u64 io_bitmap_b;
> + u64 msr_bitmap;
> +
> + u16 guest_es_selector;
> + u16 guest_cs_selector;
> + u16 guest_ss_selector;
> + u16 guest_ds_selector;
> + u16 guest_fs_selector;
> + u16 guest_gs_selector;
> + u16 guest_ldtr_selector;
> + u16 guest_tr_selector;
> +
> + u32 guest_es_limit;
> + u32 guest_cs_limit;
> + u32 guest_ss_limit;
> + u32 guest_ds_limit;
> + u32 guest_fs_limit;
> + u32 guest_gs_limit;
> + u32 guest_ldtr_limit;
> + u32 guest_tr_limit;
> + u32 guest_gdtr_limit;
> + u32 guest_idtr_limit;
> +
> + u32 guest_es_ar_bytes;
> + u32 guest_cs_ar_bytes;
> + u32 guest_ss_ar_bytes;
> + u32 guest_ds_ar_bytes;
> + u32 guest_fs_ar_bytes;
> + u32 guest_gs_ar_bytes;
> + u32 guest_ldtr_ar_bytes;
> + u32 guest_tr_ar_bytes;
> +
> + natural_width guest_es_base;
> + natural_width guest_cs_base;
> + natural_width guest_ss_base;
> + natural_width guest_ds_base;
> + natural_width guest_fs_base;
> + natural_width guest_gs_base;
> + natural_width guest_ldtr_base;
> + natural_width guest_tr_base;
> + natural_width guest_gdtr_base;
> + natural_width guest_idtr_base;
> +
> + u64 padding64_1[3];
> +
> + u64 vm_exit_msr_store_addr;
> + u64 vm_exit_msr_load_addr;
> + u64 vm_entry_msr_load_addr;
> +
> + natural_width cr3_target_value0;
> + natural_width cr3_target_value1;
> + natural_width cr3_target_value2;
> + natural_width cr3_target_value3;
> +
> + u32 page_fault_error_code_mask;
> + u32 page_fault_error_code_match;
> +
> + u32 cr3_target_count;
> + u32 vm_exit_msr_store_count;
> + u32 vm_exit_msr_load_count;
> + u32 vm_entry_msr_load_count;
> +
> + u64 tsc_offset;
> + u64 virtual_apic_page_addr;
> + u64 vmcs_link_pointer;
> +
> + u64 guest_ia32_debugctl;
> + u64 guest_ia32_pat;
> + u64 guest_ia32_efer;
> +
> + u64 guest_pdptr0;
> + u64 guest_pdptr1;
> + u64 guest_pdptr2;
> + u64 guest_pdptr3;
> +
> + natural_width guest_pending_dbg_exceptions;
> + natural_width guest_sysenter_esp;
> + natural_width guest_sysenter_eip;
> +
> + u32 guest_activity_state;
> + u32 guest_sysenter_cs;
> +
> + natural_width cr0_guest_host_mask;
> + natural_width cr4_guest_host_mask;
> + natural_width cr0_read_shadow;
> + natural_width cr4_read_shadow;
> + natural_width guest_cr0;
> + natural_width guest_cr3;
> + natural_width guest_cr4;
> + natural_width guest_dr7;
> +
> + natural_width host_fs_base;
> + natural_width host_gs_base;
> + natural_width host_tr_base;
> + natural_width host_gdtr_base;
> + natural_width host_idtr_base;
> + natural_width host_rsp;
> +
> + u64 ept_pointer;
> +
> + u16 virtual_processor_id;
> + u16 padding16[3];
> +
> + u64 padding64_2[5];
> + u64 guest_physical_address;
> +
> + u32 vm_instruction_error;
> + u32 vm_exit_reason;
> + u32 vm_exit_intr_info;
> + u32 vm_exit_intr_error_code;
> + u32 idt_vectoring_info_field;
> + u32 idt_vectoring_error_code;
> + u32 vm_exit_instruction_len;
> + u32 vmx_instruction_info;
> +
> + natural_width exit_qualification;
> + natural_width padding64_3[4];
> +
> + natural_width guest_linear_address;
> + natural_width guest_rsp;
> + natural_width guest_rflags;
> +
> + u32 guest_interruptibility_info;
> + u32 cpu_based_vm_exec_control;
> + u32 exception_bitmap;
> + u32 vm_entry_controls;
> + u32 vm_entry_intr_info_field;
> + u32 vm_entry_exception_error_code;
> + u32 vm_entry_instruction_len;
> + u32 tpr_threshold;
> +
> + natural_width guest_rip;
> +
> + u32 hv_clean_fields;
> + u32 hv_padding_32;
> + u32 hv_synthetic_controls;
> + u32 hv_enlightenments_control;
> + u32 hv_vp_id;
> +
> + u64 hv_vm_id;
> + u64 partition_assist_page;
> + u64 padding64_4[4];
> + u64 guest_bndcfgs;
> + u64 padding64_5[7];
> + u64 xss_exit_bitmap;
> + u64 padding64_6[7];
> + };
> + };
> +
> + /* Synthetic and KVM-specific fields: */
> u32 launch_state; /* set to 0 by VMCLEAR, to 1 by VMLAUNCH */
> u32 padding[7]; /* room for future expansion */
>
> - u64 io_bitmap_a;
> - u64 io_bitmap_b;
> - u64 msr_bitmap;
> - u64 vm_exit_msr_store_addr;
> - u64 vm_exit_msr_load_addr;
> - u64 vm_entry_msr_load_addr;
> - u64 tsc_offset;
> - u64 virtual_apic_page_addr;
> u64 apic_access_addr;
> u64 posted_intr_desc_addr;
> u64 vm_function_control;
> - u64 ept_pointer;
> u64 eoi_exit_bitmap0;
> 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;
> u64 pml_address;
> - u64 guest_ia32_debugctl;
> - u64 guest_ia32_pat;
> - u64 guest_ia32_efer;
> u64 guest_ia32_perf_global_ctrl;
> - u64 guest_pdptr0;
> - u64 guest_pdptr1;
> - u64 guest_pdptr2;
> - u64 guest_pdptr3;
> - u64 guest_bndcfgs;
> - u64 host_ia32_pat;
> - u64 host_ia32_efer;
> u64 host_ia32_perf_global_ctrl;
> u64 padding64[8]; /* room for future expansion */
> - /*
> - * To allow migration of L1 (complete with its L2 guests) between
> - * machines of different natural widths (32 or 64 bit), we cannot have
> - * unsigned long fields with no explict size. We use u64 (aliased
> - * natural_width) instead. Luckily, x86 is little-endian.
> - */
> - natural_width cr0_guest_host_mask;
> - natural_width cr4_guest_host_mask;
> - natural_width cr0_read_shadow;
> - natural_width cr4_read_shadow;
> - natural_width cr3_target_value0;
> - natural_width cr3_target_value1;
> - natural_width cr3_target_value2;
> - natural_width cr3_target_value3;
> - natural_width exit_qualification;
> - natural_width guest_linear_address;
> - natural_width guest_cr0;
> - natural_width guest_cr3;
> - natural_width guest_cr4;
> - natural_width guest_es_base;
> - natural_width guest_cs_base;
> - natural_width guest_ss_base;
> - natural_width guest_ds_base;
> - natural_width guest_fs_base;
> - natural_width guest_gs_base;
> - natural_width guest_ldtr_base;
> - natural_width guest_tr_base;
> - natural_width guest_gdtr_base;
> - natural_width guest_idtr_base;
> - natural_width guest_dr7;
> - natural_width guest_rsp;
> - natural_width guest_rip;
> - natural_width guest_rflags;
> - natural_width guest_pending_dbg_exceptions;
> - natural_width guest_sysenter_esp;
> - natural_width guest_sysenter_eip;
> - natural_width host_cr0;
> - natural_width host_cr3;
> - natural_width host_cr4;
> - natural_width host_fs_base;
> - natural_width host_gs_base;
> - natural_width host_tr_base;
> - natural_width host_gdtr_base;
> - natural_width host_idtr_base;
> - natural_width host_ia32_sysenter_esp;
> - natural_width host_ia32_sysenter_eip;
> - natural_width host_rsp;
> - natural_width host_rip;
> - natural_width paddingl[8]; /* room for future expansion */
> - u32 pin_based_vm_exec_control;
> - u32 cpu_based_vm_exec_control;
> - u32 exception_bitmap;
> - u32 page_fault_error_code_mask;
> - u32 page_fault_error_code_match;
> - u32 cr3_target_count;
> - u32 vm_exit_controls;
> - u32 vm_exit_msr_store_count;
> - u32 vm_exit_msr_load_count;
> - u32 vm_entry_controls;
> - u32 vm_entry_msr_load_count;
> - u32 vm_entry_intr_info_field;
> - u32 vm_entry_exception_error_code;
> - u32 vm_entry_instruction_len;
> - u32 tpr_threshold;
> - u32 secondary_vm_exec_control;
> - u32 vm_instruction_error;
> - u32 vm_exit_reason;
> - u32 vm_exit_intr_info;
> - u32 vm_exit_intr_error_code;
> - u32 idt_vectoring_info_field;
> - u32 idt_vectoring_error_code;
> - u32 vm_exit_instruction_len;
> - u32 vmx_instruction_info;
> - u32 guest_es_limit;
> - u32 guest_cs_limit;
> - u32 guest_ss_limit;
> - u32 guest_ds_limit;
> - u32 guest_fs_limit;
> - u32 guest_gs_limit;
> - u32 guest_ldtr_limit;
> - u32 guest_tr_limit;
> - u32 guest_gdtr_limit;
> - u32 guest_idtr_limit;
> - u32 guest_es_ar_bytes;
> - u32 guest_cs_ar_bytes;
> - u32 guest_ss_ar_bytes;
> - u32 guest_ds_ar_bytes;
> - u32 guest_fs_ar_bytes;
> - u32 guest_gs_ar_bytes;
> - u32 guest_ldtr_ar_bytes;
> - u32 guest_tr_ar_bytes;
> - u32 guest_interruptibility_info;
> - u32 guest_activity_state;
> - u32 guest_sysenter_cs;
> - u32 host_ia32_sysenter_cs;
> u32 vmx_preemption_timer_value;
> u32 padding32[7]; /* room for future expansion */
> - u16 virtual_processor_id;
> u16 posted_intr_nv;
> - u16 guest_es_selector;
> - u16 guest_cs_selector;
> - u16 guest_ss_selector;
> - u16 guest_ds_selector;
> - u16 guest_fs_selector;
> - u16 guest_gs_selector;
> - u16 guest_ldtr_selector;
> - u16 guest_tr_selector;
> u16 guest_intr_status;
> u16 guest_pml_index;
> - u16 host_es_selector;
> - u16 host_cs_selector;
> - u16 host_ss_selector;
> - u16 host_ds_selector;
> - u16 host_fs_selector;
> - u16 host_gs_selector;
> - u16 host_tr_selector;
> };
>
> /*
> @@ -399,7 +452,7 @@ struct __packed vmcs12 {
> * layout of struct vmcs12 is changed. MSR_IA32_VMX_BASIC returns this id, and
> * VMPTRLD verifies that the VMCS region that L1 is loading contains this id.
> */
> -#define VMCS12_REVISION 0x11e57ed0
> +#define VMCS12_REVISION 0x11e586b1
>
> /*
> * VMCS12_SIZE is the number of bytes L1 should allocate for the VMXON region
> --
> 2.14.3
>