From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Monday, June 26, 2023 8:23 PM > > In the AMD SEV-SNP guest, AP needs to be started up via sev es > save area and Hyper-V requires to call HVCALL_START_VP hypercall > to pass the gpa of sev es save area with AP's vp index and VTL(Virtual > trust level) parameters. Override wakeup_secondary_cpu_64 callback > with hv_snp_boot_ap. > > Signed-off-by: Tianyu Lan <tiala@xxxxxxxxxxxxx> > --- > arch/x86/hyperv/ivm.c | 95 +++++++++++++++++++++++++++++++ > arch/x86/include/asm/mshyperv.h | 9 +++ > arch/x86/kernel/cpu/mshyperv.c | 13 ++++- > include/asm-generic/hyperv-tlfs.h | 1 + > 4 files changed, 116 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c > index b1639ec07155..9b307f99b540 100644 > --- a/arch/x86/hyperv/ivm.c > +++ b/arch/x86/hyperv/ivm.c > @@ -22,11 +22,15 @@ > #include <asm/sev.h> > #include <asm/realmode.h> > #include <asm/e820/api.h> > +#include <asm/desc.h> > > #ifdef CONFIG_AMD_MEM_ENCRYPT > > #define GHCB_USAGE_HYPERV_CALL 1 > > +static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE); > +static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE); > + > union hv_ghcb { > struct ghcb ghcb; > struct { > @@ -449,6 +453,97 @@ __init void hv_sev_init_mem_and_cpu(void) > } > } > > +#define hv_populate_vmcb_seg(seg, gdtr_base) \ > +do { \ > + if (seg.selector) { \ > + seg.base = 0; \ > + seg.limit = HV_AP_SEGMENT_LIMIT; \ > + seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5); \ > + seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \ > + } \ > +} while (0) \ > + > +int hv_snp_boot_ap(int cpu, unsigned long start_ip) > +{ > + struct sev_es_save_area *vmsa = (struct sev_es_save_area *) > + __get_free_page(GFP_KERNEL | __GFP_ZERO); > + struct desc_ptr gdtr; > + u64 ret, rmp_adjust, retry = 5; > + struct hv_enable_vp_vtl *start_vp_input; > + unsigned long flags; > + > + native_store_gdt(&gdtr); > + > + vmsa->gdtr.base = gdtr.address; > + vmsa->gdtr.limit = gdtr.size; > + > + asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector)); > + hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base); > + > + asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector)); > + hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base); > + > + asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector)); > + hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base); > + > + asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector)); > + hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base); > + > + vmsa->efer = native_read_msr(MSR_EFER); > + > + asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4)); > + asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3)); > + asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0)); > + > + vmsa->xcr0 = 1; > + vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT; > + vmsa->rip = (u64)secondary_startup_64_no_verify; > + vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE]; > + > + /* > + * Set the SNP-specific fields for this VMSA: > + * VMPL level > + * SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits) > + */ > + vmsa->vmpl = 0; > + vmsa->sev_features = sev_status >> 2; > + > + /* > + * Running at VMPL0 allows the kernel to change the VMSA bit for a page > + * using the RMPADJUST instruction. However, for the instruction to > + * succeed it must target the permissions of a lesser privileged > + * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST > + * instruction in the AMD64 APM Volume 3). > + */ > + rmp_adjust = RMPADJUST_VMSA_PAGE_BIT | 1; > + ret = rmpadjust((unsigned long)vmsa, RMP_PG_SIZE_4K, > + rmp_adjust); > + if (ret != 0) { > + pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret); > + return ret; > + } > + > + local_irq_save(flags); > + start_vp_input = > + (struct hv_enable_vp_vtl *)ap_start_input_arg; > + memset(start_vp_input, 0, sizeof(*start_vp_input)); > + start_vp_input->partition_id = -1; > + start_vp_input->vp_index = cpu; > + start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl; > + *(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1; > + > + do { > + ret = hv_do_hypercall(HVCALL_START_VP, > + start_vp_input, NULL); > + } while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--); > + > + local_irq_restore(flags); > + > + if (!hv_result_success(ret)) > + pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret); > + return ret; > +} > + > void __init hv_vtom_init(void) > { > /* > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index 7a9a6cdc2ae9..804c67475054 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -65,6 +65,13 @@ struct memory_map_entry { > u32 reserved; > }; > > +/* > + * DEFAULT INIT GPAT and SEGMENT LIMIT value in struct VMSA > + * to start AP in enlightened SEV guest. > + */ > +#define HV_AP_INIT_GPAT_DEFAULT 0x0007040600070406ULL > +#define HV_AP_SEGMENT_LIMIT 0xffffffff > + > int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); > int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); > int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); > @@ -271,6 +278,7 @@ bool hv_ghcb_negotiate_protocol(void); > void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason); > void hv_vtom_init(void); > void hv_sev_init_mem_and_cpu(void); > +int hv_snp_boot_ap(int cpu, unsigned long start_ip); > #else > static inline void hv_ghcb_msr_write(u64 msr, u64 value) {} > static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} > @@ -278,6 +286,7 @@ static inline bool hv_ghcb_negotiate_protocol(void) { return false; } > static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {} > static inline void hv_vtom_init(void) {} > static inline void hv_sev_init_mem_and_cpu(void) {} > +static int hv_snp_boot_ap(int cpu, unsigned long start_ip) {} > #endif > > extern bool hv_isolation_type_snp(void); > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index d3bb921ee7fe..8e1d9ed6a1e0 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -295,6 +295,16 @@ static void __init hv_smp_prepare_cpus(unsigned int > max_cpus) > > native_smp_prepare_cpus(max_cpus); > > + /* > + * Override wakeup_secondary_cpu_64 callback for SEV-SNP > + * enlightened guest. > + */ > + if (hv_isolation_type_en_snp()) > + apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap; > + > + if (!hv_root_partition) > + return; > + > #ifdef CONFIG_X86_64 > for_each_present_cpu(i) { > if (i == 0) > @@ -502,8 +512,7 @@ static void __init ms_hyperv_init_platform(void) > > # ifdef CONFIG_SMP > smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; > - if (hv_root_partition) > - smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus; > + smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus; > # endif > > /* > diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h > index f4e4cc4f965f..fdac4a1714ec 100644 > --- a/include/asm-generic/hyperv-tlfs.h > +++ b/include/asm-generic/hyperv-tlfs.h > @@ -223,6 +223,7 @@ enum HV_GENERIC_SET_FORMAT { > #define HV_STATUS_INVALID_PORT_ID 17 > #define HV_STATUS_INVALID_CONNECTION_ID 18 > #define HV_STATUS_INSUFFICIENT_BUFFERS 19 > +#define HV_STATUS_TIME_OUT 120 > #define HV_STATUS_VTL_ALREADY_ENABLED 134 > > /* > -- > 2.25.1 Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>