From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> Hyper-V exposes GHCB page via SEV ES GHCB MSR for SNP guest to communicate with hypervisor. Map GHCB page for all cpus to read/write MSR register and submit hvcall request via GHCB. Hyper-V also exposes shared memory boundary via cpuid HYPERV_CPUID_ISOLATION_CONFIG and store it in the shared_gpa_boundary of ms_hyperv struct. This prepares to share memory with host for SNP guest. Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> --- arch/x86/hyperv/hv_init.c | 52 +++++++++++++++++++++++++++++++--- arch/x86/kernel/cpu/mshyperv.c | 2 ++ include/asm-generic/mshyperv.h | 14 ++++++++- 3 files changed, 63 insertions(+), 5 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 0db5137d5b81..90e65fbf4c58 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -82,6 +82,9 @@ static int hv_cpu_init(unsigned int cpu) struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()]; void **input_arg; struct page *pg; + u64 ghcb_gpa; + void *ghcb_va; + void **ghcb_base; /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */ pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0); @@ -128,6 +131,17 @@ static int hv_cpu_init(unsigned int cpu) wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val); } + if (ms_hyperv.ghcb_base) { + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); + + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE); + if (!ghcb_va) + return -ENOMEM; + + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base); + *ghcb_base = ghcb_va; + } + return 0; } @@ -223,6 +237,7 @@ static int hv_cpu_die(unsigned int cpu) unsigned long flags; void **input_arg; void *pg; + void **ghcb_va = NULL; local_irq_save(flags); input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); @@ -236,6 +251,13 @@ static int hv_cpu_die(unsigned int cpu) *output_arg = NULL; } + if (ms_hyperv.ghcb_base) { + ghcb_va = (void **)this_cpu_ptr(ms_hyperv.ghcb_base); + if (*ghcb_va) + iounmap(*ghcb_va); + *ghcb_va = NULL; + } + local_irq_restore(flags); free_pages((unsigned long)pg, hv_root_partition ? 1 : 0); @@ -372,6 +394,9 @@ void __init hyperv_init(void) u64 guest_id, required_msrs; union hv_x64_msr_hypercall_contents hypercall_msr; int cpuhp, i; + u64 ghcb_gpa; + void *ghcb_va; + void **ghcb_base; if (x86_hyper_type != X86_HYPER_MS_HYPERV) return; @@ -432,9 +457,24 @@ void __init hyperv_init(void) VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, __builtin_return_address(0)); - if (hv_hypercall_pg == NULL) { - wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); - goto remove_cpuhp_state; + if (hv_hypercall_pg == NULL) + goto clean_guest_os_id; + + if (hv_isolation_type_snp()) { + ms_hyperv.ghcb_base = alloc_percpu(void *); + if (!ms_hyperv.ghcb_base) + goto clean_guest_os_id; + + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE); + if (!ghcb_va) { + free_percpu(ms_hyperv.ghcb_base); + ms_hyperv.ghcb_base = NULL; + goto clean_guest_os_id; + } + + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base); + *ghcb_base = ghcb_va; } rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); @@ -499,7 +539,8 @@ void __init hyperv_init(void) return; -remove_cpuhp_state: +clean_guest_os_id: + wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); cpuhp_remove_state(cpuhp); free_vp_assist_page: kfree(hv_vp_assist_page); @@ -528,6 +569,9 @@ void hyperv_cleanup(void) */ hv_hypercall_pg = NULL; + if (ms_hyperv.ghcb_base) + free_percpu(ms_hyperv.ghcb_base); + /* Reset the hypercall page */ hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 347c32eac8fd..d6c363456cbf 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -330,6 +330,8 @@ static void __init ms_hyperv_init_platform(void) if (ms_hyperv.features_b & HV_ISOLATION) { ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG); ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG); + ms_hyperv.shared_gpa_boundary = + (u64)1 << ms_hyperv.shared_gpa_boundary_bits; pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n", ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b); diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index dff58a3db5d5..ad0e33776668 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -34,7 +34,19 @@ struct ms_hyperv_info { u32 max_vp_index; u32 max_lp_index; u32 isolation_config_a; - u32 isolation_config_b; + union + { + u32 isolation_config_b;; + struct { + u32 cvm_type : 4; + u32 Reserved11 : 1; + u32 shared_gpa_boundary_active : 1; + u32 shared_gpa_boundary_bits : 6; + u32 Reserved12 : 20; + }; + }; + void __percpu **ghcb_base; + u64 shared_gpa_boundary; }; extern struct ms_hyperv_info ms_hyperv; -- 2.25.1