On 20.09.23 06:52, Saurabh Sengar wrote:
> 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 <[email protected]>
> Closes:
> https://lore.kernel.org/lkml/[email protected]/
> Signed-off-by: Saurabh Sengar <[email protected]>
> ---
> This patch is dependent on :
> https://lore.kernel.org/lkml/[email protected]/
>
> 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();
> +
As the kernel's console will already be initialized when this code gets
executed, the possible panic() in hv_vtl_early_init() will actually be
visible, thereby...
> 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>
Acked-by: Mathias Krause <[email protected]>
Thanks!
