On Wed, Mar 11, 2026 at 12:34:57PM +0100, Magnus Kulke wrote:
> When using the extended request format we can instruct the hypervisor to
> provision enough space for requested XSAVE features. This is required
> for supporting QEMU models provided via the -cpu flag properly.
>
> Signed-off-by: Magnus Kulke <[email protected]>
> ---
> accel/mshv/mshv-all.c | 75 +++++++++++--
> include/hw/hyperv/hvgdk_mini.h | 2 +
> include/hw/hyperv/hvhdk.h | 195 +++++++++++++++++++++++++++++++++
> 3 files changed, 265 insertions(+), 7 deletions(-)
>
> diff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c
> index d4cc7f5371..eab967ff07 100644
> --- a/accel/mshv/mshv-all.c
> +++ b/accel/mshv/mshv-all.c
> @@ -110,21 +110,82 @@ static int resume_vm(int vm_fd)
> return 0;
> }
>
> +static int get_host_partition_property(int mshv_fd, uint32_t feature_bank,
Why not just call the param property_code instead of feature_bank? That
way this function can be used for other properties too.
> + uint64_t *value)
> +{
> + int ret;
> + struct hv_input_get_partition_property in = {0};
> + struct hv_output_get_partition_property out = {0};
> + struct mshv_root_hvcall args = {0};
> +
> + in.property_code = feature_bank;
> +
> + args.code = HVCALL_GET_PARTITION_PROPERTY;
> + args.in_sz = sizeof(in);
> + args.in_ptr = (uint64_t)∈
> + args.out_sz = sizeof(out);
> + args.out_ptr = (uint64_t)&out;
> +
> + ret = ioctl(mshv_fd, MSHV_ROOT_HVCALL, &args);
> + if (ret < 0) {
> + error_report("Failed to get host partition property bank: %s",
> + strerror(errno));
> + return -1;
> + }
> +
> + *value = out.property_value;
> + return 0;
> +}
> +
> static int create_partition(int mshv_fd, int *vm_fd)
> {
> int ret;
> - struct mshv_create_partition args = {0};
> + uint64_t pt_flags, host_proc_features;
> + union hv_partition_processor_xsave_features disabled_xsave_features;
> + struct mshv_create_partition_v2 args = {0};
> + uint32_t feature_banks[] = {
> + HV_PARTITION_PROPERTY_PROCESSOR_FEATURES0,
> + HV_PARTITION_PROPERTY_PROCESSOR_FEATURES1,
> + };
> +
> + QEMU_BUILD_BUG_ON(ARRAY_SIZE(feature_banks) >
> MSHV_NUM_CPU_FEATURES_BANKS);
Is this really useful since we're not using the feature_banks array
anywhere?
Thanks,
Anirudh.
>
> /* Initialize pt_flags with the desired features */
> - uint64_t pt_flags = (1ULL << MSHV_PT_BIT_LAPIC) |
> - (1ULL << MSHV_PT_BIT_X2APIC) |
> - (1ULL << MSHV_PT_BIT_GPA_SUPER_PAGES);
> + pt_flags = (1ULL << MSHV_PT_BIT_LAPIC) |
> + (1ULL << MSHV_PT_BIT_X2APIC) |
> + (1ULL << MSHV_PT_BIT_GPA_SUPER_PAGES) |
> + (1ULL << MSHV_PT_BIT_CPU_AND_XSAVE_FEATURES);
> +
> + /* enable all */
> + disabled_xsave_features.as_uint64 = 0;
> +
> + /*
> + * query host for supported processor features and disable unsupported
> + * features: (0 means supported, 1 means disabled, hence the negation)
> + */
> + ret = get_host_partition_property(mshv_fd,
> +
> HV_PARTITION_PROPERTY_PROCESSOR_FEATURES0,
> + &host_proc_features);
> + if (ret < 0) {
> + error_report("Failed to get host processor feature bank 0");
> + return -1;
> + }
> + args.pt_cpu_fbanks[0] = ~host_proc_features;
>
> - /* Set default isolation type */
> - uint64_t pt_isolation = MSHV_PT_ISOLATION_NONE;
> + ret = get_host_partition_property(mshv_fd,
> +
> HV_PARTITION_PROPERTY_PROCESSOR_FEATURES1,
> + &host_proc_features);
> + if (ret < 0) {
> + error_report("Failed to get host processor feature bank 1");
> + return -1;
> + }
> + args.pt_cpu_fbanks[1] = ~host_proc_features;
>
> + /* populate args structure */
> args.pt_flags = pt_flags;
> - args.pt_isolation = pt_isolation;
> + args.pt_isolation = MSHV_PT_ISOLATION_NONE;
> + args.pt_disabled_xsave = disabled_xsave_features.as_uint64;
> + args.pt_num_cpu_fbanks = MSHV_NUM_CPU_FEATURES_BANKS;
>
> ret = ioctl(mshv_fd, MSHV_CREATE_PARTITION, &args);
> if (ret < 0) {
> diff --git a/include/hw/hyperv/hvgdk_mini.h b/include/hw/hyperv/hvgdk_mini.h
> index 7d7b2e9b36..a8d4b2b2b1 100644
> --- a/include/hw/hyperv/hvgdk_mini.h
> +++ b/include/hw/hyperv/hvgdk_mini.h
> @@ -456,6 +456,8 @@ typedef struct hv_input_set_vp_registers {
> struct hv_register_assoc elements[];
> } QEMU_PACKED hv_input_set_vp_registers;
>
> +#define MSHV_VP_MAX_REGISTERS 128
> +
> union hv_interrupt_control {
> uint64_t as_uint64;
> struct {
> diff --git a/include/hw/hyperv/hvhdk.h b/include/hw/hyperv/hvhdk.h
> index bf2f8cbc27..a6893f4ca3 100644
> --- a/include/hw/hyperv/hvhdk.h
> +++ b/include/hw/hyperv/hvhdk.h
> @@ -13,6 +13,16 @@
>
> #define HV_PARTITION_SYNTHETIC_PROCESSOR_FEATURES_BANKS 1
>
> +struct hv_input_get_partition_property {
> + uint64_t partition_id;
> + uint32_t property_code; /* enum hv_partition_property_code */
> + uint32_t padding;
> +} QEMU_PACKED;
> +
> +struct hv_output_get_partition_property {
> + uint64_t property_value;
> +} QEMU_PACKED;
> +
> struct hv_input_set_partition_property {
> uint64_t partition_id;
> uint32_t property_code; /* enum hv_partition_property_code */
> @@ -163,6 +173,191 @@ union hv_partition_synthetic_processor_features {
> };
> };
>
> +union hv_partition_processor_xsave_features {
> + struct {
> + uint64_t xsave_support:1;
> + uint64_t xsaveopt_support:1;
> + uint64_t avx_support:1;
> + uint64_t avx2_support:1;
> + uint64_t fma_support:1;
> + uint64_t mpx_support:1;
> + uint64_t avx512_support:1;
> + uint64_t avx512_dq_support:1;
> + uint64_t avx512_cd_support:1;
> + uint64_t avx512_bw_support:1;
> + uint64_t avx512_vl_support:1;
> + uint64_t xsave_comp_support:1;
> + uint64_t xsave_supervisor_support:1;
> + uint64_t xcr1_support:1;
> + uint64_t avx512_bitalg_support:1;
> + uint64_t avx512_i_fma_support:1;
> + uint64_t avx512_v_bmi_support:1;
> + uint64_t avx512_v_bmi2_support:1;
> + uint64_t avx512_vnni_support:1;
> + uint64_t gfni_support:1;
> + uint64_t vaes_support:1;
> + uint64_t avx512_v_popcntdq_support:1;
> + uint64_t vpclmulqdq_support:1;
> + uint64_t avx512_bf16_support:1;
> + uint64_t avx512_vp2_intersect_support:1;
> + uint64_t avx512_fp16_support:1;
> + uint64_t xfd_support:1;
> + uint64_t amx_tile_support:1;
> + uint64_t amx_bf16_support:1;
> + uint64_t amx_int8_support:1;
> + uint64_t avx_vnni_support:1;
> + uint64_t avx_ifma_support:1;
> + uint64_t avx_ne_convert_support:1;
> + uint64_t avx_vnni_int8_support:1;
> + uint64_t avx_vnni_int16_support:1;
> + uint64_t avx10_1_256_support:1;
> + uint64_t avx10_1_512_support:1;
> + uint64_t amx_fp16_support:1;
> + uint64_t reserved1:26;
> + };
> + uint64_t as_uint64;
> +};
> +
> +#define HV_PARTITION_PROCESSOR_FEATURES_BANKS 2
> +#define HV_PARTITION_PROCESSOR_FEATURES_RESERVEDBANK1_BITFIELD_COUNT 4
> +
> +
> +union hv_partition_processor_features {
> + uint64_t as_uint64[HV_PARTITION_PROCESSOR_FEATURES_BANKS];
> + struct {
> + uint64_t sse3_support:1;
> + uint64_t lahf_sahf_support:1;
> + uint64_t ssse3_support:1;
> + uint64_t sse4_1_support:1;
> + uint64_t sse4_2_support:1;
> + uint64_t sse4a_support:1;
> + uint64_t xop_support:1;
> + uint64_t pop_cnt_support:1;
> + uint64_t cmpxchg16b_support:1;
> + uint64_t altmovcr8_support:1;
> + uint64_t lzcnt_support:1;
> + uint64_t mis_align_sse_support:1;
> + uint64_t mmx_ext_support:1;
> + uint64_t amd3dnow_support:1;
> + uint64_t extended_amd3dnow_support:1;
> + uint64_t page_1gb_support:1;
> + uint64_t aes_support:1;
> + uint64_t pclmulqdq_support:1;
> + uint64_t pcid_support:1;
> + uint64_t fma4_support:1;
> + uint64_t f16c_support:1;
> + uint64_t rd_rand_support:1;
> + uint64_t rd_wr_fs_gs_support:1;
> + uint64_t smep_support:1;
> + uint64_t enhanced_fast_string_support:1;
> + uint64_t bmi1_support:1;
> + uint64_t bmi2_support:1;
> + uint64_t hle_support_deprecated:1;
> + uint64_t rtm_support_deprecated:1;
> + uint64_t movbe_support:1;
> + uint64_t npiep1_support:1;
> + uint64_t dep_x87_fpu_save_support:1;
> + uint64_t rd_seed_support:1;
> + uint64_t adx_support:1;
> + uint64_t intel_prefetch_support:1;
> + uint64_t smap_support:1;
> + uint64_t hle_support:1;
> + uint64_t rtm_support:1;
> + uint64_t rdtscp_support:1;
> + uint64_t clflushopt_support:1;
> + uint64_t clwb_support:1;
> + uint64_t sha_support:1;
> + uint64_t x87_pointers_saved_support:1;
> + uint64_t invpcid_support:1;
> + uint64_t ibrs_support:1;
> + uint64_t stibp_support:1;
> + uint64_t ibpb_support:1;
> + uint64_t unrestricted_guest_support:1;
> + uint64_t mdd_support:1;
> + uint64_t fast_short_rep_mov_support:1;
> + uint64_t l1dcache_flush_support:1;
> + uint64_t rdcl_no_support:1;
> + uint64_t ibrs_all_support:1;
> + uint64_t skip_l1df_support:1;
> + uint64_t ssb_no_support:1;
> + uint64_t rsb_a_no_support:1;
> + uint64_t virt_spec_ctrl_support:1;
> + uint64_t rd_pid_support:1;
> + uint64_t umip_support:1;
> + uint64_t mbs_no_support:1;
> + uint64_t mb_clear_support:1;
> + uint64_t taa_no_support:1;
> + uint64_t tsx_ctrl_support:1;
> + uint64_t reserved_bank0:1;
> +
> + /* N.B. Begin bank 1 processor features. */
> + uint64_t a_count_m_count_support:1;
> + uint64_t tsc_invariant_support:1;
> + uint64_t cl_zero_support:1;
> + uint64_t rdpru_support:1;
> + uint64_t la57_support:1;
> + uint64_t mbec_support:1;
> + uint64_t nested_virt_support:1;
> + uint64_t psfd_support:1;
> + uint64_t cet_ss_support:1;
> + uint64_t cet_ibt_support:1;
> + uint64_t vmx_exception_inject_support:1;
> + uint64_t enqcmd_support:1;
> + uint64_t umwait_tpause_support:1;
> + uint64_t movdiri_support:1;
> + uint64_t movdir64b_support:1;
> + uint64_t cldemote_support:1;
> + uint64_t serialize_support:1;
> + uint64_t tsc_deadline_tmr_support:1;
> + uint64_t tsc_adjust_support:1;
> + uint64_t fzl_rep_movsb:1;
> + uint64_t fs_rep_stosb:1;
> + uint64_t fs_rep_cmpsb:1;
> + uint64_t tsx_ld_trk_support:1;
> + uint64_t vmx_ins_outs_exit_info_support:1;
> + uint64_t hlat_support:1;
> + uint64_t sbdr_ssdp_no_support:1;
> + uint64_t fbsdp_no_support:1;
> + uint64_t psdp_no_support:1;
> + uint64_t fb_clear_support:1;
> + uint64_t btc_no_support:1;
> + uint64_t ibpb_rsb_flush_support:1;
> + uint64_t stibp_always_on_support:1;
> + uint64_t perf_global_ctrl_support:1;
> + uint64_t npt_execute_only_support:1;
> + uint64_t npt_ad_flags_support:1;
> + uint64_t npt1_gb_page_support:1;
> + uint64_t amd_processor_topology_node_id_support:1;
> + uint64_t local_machine_check_support:1;
> + uint64_t extended_topology_leaf_fp256_amd_support:1;
> + uint64_t gds_no_support:1;
> + uint64_t cmpccxadd_support:1;
> + uint64_t tsc_aux_virtualization_support:1;
> + uint64_t rmp_query_support:1;
> + uint64_t bhi_no_support:1;
> + uint64_t bhi_dis_support:1;
> + uint64_t prefetch_i_support:1;
> + uint64_t sha512_support:1;
> + uint64_t mitigation_ctrl_support:1;
> + uint64_t rfds_no_support:1;
> + uint64_t rfds_clear_support:1;
> + uint64_t sm3_support:1;
> + uint64_t sm4_support:1;
> + uint64_t secure_avic_support:1;
> + uint64_t guest_intercept_ctrl_support:1;
> + uint64_t sbpb_supported:1;
> + uint64_t ibpb_br_type_supported:1;
> + uint64_t srso_no_supported:1;
> + uint64_t srso_user_kernel_no_supported:1;
> + uint64_t vrew_clear_supported:1;
> + uint64_t tsa_l1_no_supported:1;
> + uint64_t tsa_sq_no_supported:1;
> + uint64_t lass_support:1;
> + uint64_t idle_hlt_intercept_support:1;
> + uint64_t msr_list_support:1;
> + };
> +};
> +
> enum hv_translate_gva_result_code {
> HV_TRANSLATE_GVA_SUCCESS = 0,
>
> --
> 2.34.1
>
>
