diff mbox series

[4/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests

Message ID 20221121195151.21812-5-decui@microsoft.com
State New
Headers
Series Support TDX guests on Hyper-V |

Commit Message

Dexuan Cui Nov. 21, 2022, 7:51 p.m. UTC 
  No logic change to SNP/VBS guests.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 arch/x86/hyperv/ivm.c              |  7 +++++++
 arch/x86/include/asm/hyperv-tlfs.h |  3 ++-
 arch/x86/include/asm/mshyperv.h    |  3 +++
 arch/x86/kernel/cpu/mshyperv.c     | 18 ++++++++++++++++--
 drivers/hv/hv_common.c             |  6 ++++++
 5 files changed, 34 insertions(+), 3 deletions(-)

Comments

Dave Hansen Nov. 21, 2022, 9:01 p.m. UTC | #1 
On 11/21/22 11:51, Dexuan Cui wrote:
> +			switch (hv_get_isolation_type()) {
> +			case HV_ISOLATION_TYPE_VBS:
> +			case HV_ISOLATION_TYPE_SNP:
>  				cc_set_vendor(CC_VENDOR_HYPERV);
> +				break;
> +
> +			case HV_ISOLATION_TYPE_TDX:
> +				static_branch_enable(&isolation_type_tdx);
> +				break;

This makes zero logical sense to me.

Running on Hyper-V, a HV_ISOLATION_TYPE_SNP is CC_VENDOR_HYPERV, but a
HV_ISOLATION_TYPE_TDX guest is *NOT* CC_VENDOR_HYPERV?
Borislav Petkov Nov. 21, 2022, 9:48 p.m. UTC | #2 
On Mon, Nov 21, 2022 at 01:01:45PM -0800, Dave Hansen wrote:
> On 11/21/22 11:51, Dexuan Cui wrote:
> > +			switch (hv_get_isolation_type()) {
> > +			case HV_ISOLATION_TYPE_VBS:
> > +			case HV_ISOLATION_TYPE_SNP:
> >  				cc_set_vendor(CC_VENDOR_HYPERV);
> > +				break;
> > +
> > +			case HV_ISOLATION_TYPE_TDX:
> > +				static_branch_enable(&isolation_type_tdx);
> > +				break;
> 
> This makes zero logical sense to me.
> 
> Running on Hyper-V, a HV_ISOLATION_TYPE_SNP is CC_VENDOR_HYPERV, but a
> HV_ISOLATION_TYPE_TDX guest is *NOT* CC_VENDOR_HYPERV?

https://lore.kernel.org/r/Y3uTK3rBV6eXSJnC@zn.tnic
Kuppuswamy Sathyanarayanan Nov. 22, 2022, 12:32 a.m. UTC | #3 
On 11/21/22 11:51 AM, Dexuan Cui wrote:
> No logic change to SNP/VBS guests.

Add some info on how and where you are going to use this function.

> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
>  arch/x86/hyperv/ivm.c              |  7 +++++++
>  arch/x86/include/asm/hyperv-tlfs.h |  3 ++-
>  arch/x86/include/asm/mshyperv.h    |  3 +++
>  arch/x86/kernel/cpu/mshyperv.c     | 18 ++++++++++++++++--
>  drivers/hv/hv_common.c             |  6 ++++++
>  5 files changed, 34 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 1dbcbd9da74d..0c219f163f71 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -269,6 +269,13 @@ bool hv_isolation_type_snp(void)
>  	return static_branch_unlikely(&isolation_type_snp);
>  }
>  
> +DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
> +
> +bool hv_isolation_type_tdx(void)
> +{
> +	return static_branch_unlikely(&isolation_type_tdx);
> +}

Does it need #ifdef CONFIG_INTEL_TDX_GUEST? If not TDX, you can
live with weak reference.

> +
>  /*
>   * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
>   *
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index 6d9368ea3701..6c0a04d078f5 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -161,7 +161,8 @@
>  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 fc09b6739922..9d593ab2be26 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -14,6 +14,7 @@
>  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,
> @@ -32,6 +33,8 @@ 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 831613959a92..9ad0b0abf0e0 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -338,9 +338,23 @@ static void __init ms_hyperv_init_platform(void)
>  #endif
>  		}
>  		/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
> -		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
> -			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
> +		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) ||
> +		    IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) {
> +
> +			switch (hv_get_isolation_type()) {
> +			case HV_ISOLATION_TYPE_VBS:
> +			case HV_ISOLATION_TYPE_SNP:
>  				cc_set_vendor(CC_VENDOR_HYPERV);
> +				break;
> +
> +			case HV_ISOLATION_TYPE_TDX:
> +				static_branch_enable(&isolation_type_tdx);
> +				break;
> +

It is not clear why you need special handling for TDX?

> +			default:
> +				WARN_ON(1);
> +				break;
> +			}
>  		}
>  	}
>  
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index ae68298c0dca..a9a03ab04b97 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -268,6 +268,12 @@ 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))
>  {
>  }
Dexuan Cui Nov. 23, 2022, 7:13 p.m. UTC | #4 
> From: Sathyanarayanan Kuppuswamy
> <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> On 11/21/22 11:51 AM, Dexuan Cui wrote:
> > No logic change to SNP/VBS guests.
> 
> Add some info on how and where you are going to use this function.

Will do.

> > +DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
> > +
> > +bool hv_isolation_type_tdx(void)
> > +{
> > +	return static_branch_unlikely(&isolation_type_tdx);
> > +}
> 
> Does it need #ifdef CONFIG_INTEL_TDX_GUEST? If not TDX, you can
> live with weak reference.

Will add the #ifdef.

> > -		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
> > -			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
> > +		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) ||
> > +		    IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) {
> > +
> > +			switch (hv_get_isolation_type()) {
> > +			case HV_ISOLATION_TYPE_VBS:
> > +			case HV_ISOLATION_TYPE_SNP:
> >  				cc_set_vendor(CC_VENDOR_HYPERV);
> > +				break;
> > +
> > +			case HV_ISOLATION_TYPE_TDX:
> > +				static_branch_enable(&isolation_type_tdx);
> > +				break;
> > +
> 
> It is not clear why you need special handling for TDX?

It's being discussed in another thread:
https://lwn.net/ml/linux-kernel/BYAPR21MB16886FF8B35F51964A515CD5D70C9@BYAPR21MB1688.namprd21.prod.outlook.com/

I'll wait for Michael Kelley's v4 and rebase my patches accordingly.
diff mbox series

Patch

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 1dbcbd9da74d..0c219f163f71 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -269,6 +269,13 @@  bool hv_isolation_type_snp(void)
 	return static_branch_unlikely(&isolation_type_snp);
 }
 
+DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
+
+bool hv_isolation_type_tdx(void)
+{
+	return static_branch_unlikely(&isolation_type_tdx);
+}
+
 /*
  * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
  *
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 6d9368ea3701..6c0a04d078f5 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -161,7 +161,8 @@ 
 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 fc09b6739922..9d593ab2be26 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -14,6 +14,7 @@ 
 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,
@@ -32,6 +33,8 @@  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 831613959a92..9ad0b0abf0e0 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -338,9 +338,23 @@  static void __init ms_hyperv_init_platform(void)
 #endif
 		}
 		/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
-		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
+		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) ||
+		    IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) {
+
+			switch (hv_get_isolation_type()) {
+			case HV_ISOLATION_TYPE_VBS:
+			case HV_ISOLATION_TYPE_SNP:
 				cc_set_vendor(CC_VENDOR_HYPERV);
+				break;
+
+			case HV_ISOLATION_TYPE_TDX:
+				static_branch_enable(&isolation_type_tdx);
+				break;
+
+			default:
+				WARN_ON(1);
+				break;
+			}
 		}
 	}
 
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298c0dca..a9a03ab04b97 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -268,6 +268,12 @@  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))
 {
 }