RE: [PATCH v4 3/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests

[Michael Kelley (LINUX)]

From: Dexuan Cui <decui@xxxxxxxxxxxxx> Sent: Saturday, April 8, 2023 1:48 PM
> 
> No logic change to SNP/VBS guests.
> 
> hv_isolation_type_tdx() wil be used to instruct a TDX guest on Hyper-V to
> do some TDX-specific operations, e.g. hv_do_hypercall() should use
> __tdx_hypercall(), and a TDX guest on Hyper-V should handle the Hyper-V
> Event/Message/Monitor pages specially.
> 
> Reviewed-by: Kuppuswamy Sathyanarayanan
> <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> ---
>  arch/x86/hyperv/ivm.c              | 6 ++++++
>  arch/x86/include/asm/hyperv-tlfs.h | 3 ++-
>  arch/x86/include/asm/mshyperv.h    | 3 +++
>  arch/x86/kernel/cpu/mshyperv.c     | 2 ++
>  drivers/hv/hv_common.c             | 6 ++++++
>  5 files changed, 19 insertions(+), 1 deletion(-)
> 
> Changes in v2:
>   Added "#ifdef CONFIG_INTEL_TDX_GUEST and #endif" for
>     hv_isolation_type_tdx() in arch/x86/hyperv/ivm.c.
> 
>     Simplified the changes in ms_hyperv_init_platform().
> 
> Changes in v3:
>   Added Kuppuswamy's Reviewed-by.
> 
> Changes in v4:
>   A minor rebase to Michael's v7 DDA patchset.
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 127d5b7b63de1..3658ade4f4121 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -400,6 +400,7 @@ bool hv_is_isolation_supported(void)
>  }
> 
>  DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
> +DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
> 
>  /*
>   * hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
> @@ -409,3 +410,8 @@ bool hv_isolation_type_snp(void)
>  {
>  	return static_branch_unlikely(&isolation_type_snp);
>  }
> +
> +bool hv_isolation_type_tdx(void)
> +{
> +	return static_branch_unlikely(&isolation_type_tdx);
> +}
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index b4fb75bd10138..338f383c721c9 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -169,7 +169,8 @@
>  enum hv_isolation_type {
>  	HV_ISOLATION_TYPE_NONE	= 0,
>  	HV_ISOLATION_TYPE_VBS	= 1,
> -	HV_ISOLATION_TYPE_SNP	= 2
> +	HV_ISOLATION_TYPE_SNP	= 2,
> +	HV_ISOLATION_TYPE_TDX	= 3
>  };
> 
>  /* Hyper-V specific model specific registers (MSRs) */
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index e3cef98a01420..de7ceae9e65e9 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -22,6 +22,7 @@
>  union hv_ghcb;
> 
>  DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
> +DECLARE_STATIC_KEY_FALSE(isolation_type_tdx);
> 
>  typedef int (*hyperv_fill_flush_list_func)(
>  		struct hv_guest_mapping_flush_list *flush,
> @@ -38,6 +39,8 @@ extern u64 hv_current_partition_id;
> 
>  extern union hv_ghcb * __percpu *hv_ghcb_pg;
> 
> +extern bool hv_isolation_type_tdx(void);
> +
>  int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
>  int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
>  int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index ff348ebb6ae28..a87fb934cd4b4 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -405,6 +405,8 @@ static void __init ms_hyperv_init_platform(void)
> 
>  		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
>  			static_branch_enable(&isolation_type_snp);
> +		else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX)
> +			static_branch_enable(&isolation_type_tdx);
>  	}
> 
>  	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index 6d40b6c7b23b9..c55db7ea6580b 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -271,6 +271,12 @@ bool __weak hv_isolation_type_snp(void)
>  }
>  EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
> 
> +bool __weak hv_isolation_type_tdx(void)
> +{
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
> +
>  void __weak hv_setup_vmbus_handler(void (*handler)(void))
>  {
>  }
> --
> 2.25.1

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>