There has been cases reported where HYPERV_VTL_MODE is enabled by mistake, on a non Hyper-V platforms. This causes the hv_vtl_early_init function to be called in an non Hyper-V/VTL platforms which results the memory corruption.
Remove the early_initcall for vhv_vtl_early_init and call it at the end of hyperv_init to make sure it is never called in a non Hyper-V platform by mistake. Reported-by: Mathias Krause <mini...@grsecurity.net> Closes: https://lore.kernel.org/lkml/40467722-f4ab-19a5-4989-308225b1f...@grsecurity.net/ Signed-off-by: Saurabh Sengar <ssen...@linux.microsoft.com> --- This patch is dependent on : https://lore.kernel.org/lkml/1695182675-13405-1-git-send-email-ssen...@linux.microsoft.com/ arch/x86/hyperv/hv_init.c | 3 +++ arch/x86/hyperv/hv_vtl.c | 3 +-- arch/x86/include/asm/mshyperv.h | 2 ++ 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index f0128fd4031d..608f4fe41fb7 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -610,6 +610,9 @@ void __init hyperv_init(void) /* Find the VTL */ ms_hyperv.vtl = get_vtl(); + if (ms_hyperv.vtl > 0) /* non default VTL */ + hv_vtl_early_init(); + return; clean_guest_os_id: diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 36a562218010..999f5ac82fe9 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -215,7 +215,7 @@ static int hv_vtl_wakeup_secondary_cpu(int apicid, unsigned long start_eip) return hv_vtl_bringup_vcpu(vp_id, start_eip); } -static int __init hv_vtl_early_init(void) +int __init hv_vtl_early_init(void) { /* * `boot_cpu_has` returns the runtime feature support, @@ -230,4 +230,3 @@ static int __init hv_vtl_early_init(void) return 0; } -early_initcall(hv_vtl_early_init); diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 033b53f993c6..83019c3aaae9 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -340,8 +340,10 @@ static inline u64 hv_get_non_nested_register(unsigned int reg) { return 0; } #ifdef CONFIG_HYPERV_VTL_MODE void __init hv_vtl_init_platform(void); +int __init hv_vtl_early_init(void); #else static inline void __init hv_vtl_init_platform(void) {} +static int __init hv_vtl_early_init(void) {} #endif #include <asm-generic/mshyperv.h> -- 2.34.1
