From 0cc4f6d9f0b9f20f3f1e1149bdb6737c0b4e134a Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Mon, 25 Oct 2021 08:21:06 -0400 Subject: x86/hyperv: Initialize GHCB page in Isolation VM Hyperv 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 page. Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 68 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 61 insertions(+), 7 deletions(-) (limited to 'arch/x86/hyperv/hv_init.c') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 708a2712a516..a7e922755ad1 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -36,12 +37,42 @@ EXPORT_SYMBOL_GPL(hv_current_partition_id); void *hv_hypercall_pg; EXPORT_SYMBOL_GPL(hv_hypercall_pg); +void __percpu **hv_ghcb_pg; + /* Storage to save the hypercall page temporarily for hibernation */ static void *hv_hypercall_pg_saved; struct hv_vp_assist_page **hv_vp_assist_page; EXPORT_SYMBOL_GPL(hv_vp_assist_page); +static int hyperv_init_ghcb(void) +{ + u64 ghcb_gpa; + void *ghcb_va; + void **ghcb_base; + + if (!hv_isolation_type_snp()) + return 0; + + if (!hv_ghcb_pg) + return -EINVAL; + + /* + * GHCB page is allocated by paravisor. The address + * returned by MSR_AMD64_SEV_ES_GHCB is above shared + * memory boundary and map it here. + */ + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); + ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB); + if (!ghcb_va) + return -ENOMEM; + + ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg); + *ghcb_base = ghcb_va; + + return 0; +} + static int hv_cpu_init(unsigned int cpu) { union hv_vp_assist_msr_contents msr = { 0 }; @@ -85,7 +116,7 @@ static int hv_cpu_init(unsigned int cpu) } } - return 0; + return hyperv_init_ghcb(); } static void (*hv_reenlightenment_cb)(void); @@ -177,6 +208,14 @@ static int hv_cpu_die(unsigned int cpu) { struct hv_reenlightenment_control re_ctrl; unsigned int new_cpu; + void **ghcb_va; + + if (hv_ghcb_pg) { + ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg); + if (*ghcb_va) + memunmap(*ghcb_va); + *ghcb_va = NULL; + } hv_common_cpu_die(cpu); @@ -366,10 +405,16 @@ void __init hyperv_init(void) goto common_free; } + if (hv_isolation_type_snp()) { + hv_ghcb_pg = alloc_percpu(void *); + if (!hv_ghcb_pg) + goto free_vp_assist_page; + } + cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", hv_cpu_init, hv_cpu_die); if (cpuhp < 0) - goto free_vp_assist_page; + goto free_ghcb_page; /* * Setup the hypercall page and enable hypercalls. @@ -383,10 +428,8 @@ 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; rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); hypercall_msr.enable = 1; @@ -456,8 +499,11 @@ void __init hyperv_init(void) hv_query_ext_cap(0); return; -remove_cpuhp_state: +clean_guest_os_id: + wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); cpuhp_remove_state(cpuhp); +free_ghcb_page: + free_percpu(hv_ghcb_pg); free_vp_assist_page: kfree(hv_vp_assist_page); hv_vp_assist_page = NULL; @@ -559,3 +605,11 @@ bool hv_is_isolation_supported(void) { return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; } + +DEFINE_STATIC_KEY_FALSE(isolation_type_snp); + +bool hv_isolation_type_snp(void) +{ + return static_branch_unlikely(&isolation_type_snp); +} +EXPORT_SYMBOL_GPL(hv_isolation_type_snp); -- cgit