diff options
Diffstat (limited to 'arch/x86/hyperv')
| -rw-r--r-- | arch/x86/hyperv/hv_init.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 1608050e9df9..dd92d8b438d4 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -111,8 +111,17 @@ static int hv_cpu_init(unsigned int cpu) if (!hv_vp_assist_page) return 0; - if (!*hvp) - *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); + /* + * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section + * 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure + * we always write the EOI MSR in hv_apic_eoi_write() *after* the + * EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may + * not be stopped in the case of CPU offlining and the VM will hang. + */ + if (!*hvp) { + *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO, + PAGE_KERNEL); + } if (*hvp) { u64 val; |