diff mbox series

[v2,02/12] mm: Introduce a function to check for virtualization protection features

Message ID 482fe51f1671c1cd081039801b03db7ec0036332.1628873970.git.thomas.lendacky@amd.com (mailing list archive)
State Not Applicable
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Series Implement generic prot_guest_has() helper function | expand
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Commit Message

Tom Lendacky Aug. 13, 2021, 4:59 p.m. UTC
In prep for other protected virtualization technologies, introduce a
generic helper function, prot_guest_has(), that can be used to check
for specific protection attributes, like memory encryption. This is
intended to eliminate having to add multiple technology-specific checks
to the code (e.g. if (sev_active() || tdx_active())).

Reviewed-by: Joerg Roedel <jroedel@suse.de>
Co-developed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/Kconfig                    |  3 +++
 include/linux/protected_guest.h | 35 +++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 include/linux/protected_guest.h

Comments

Kuppuswamy Sathyanarayanan Aug. 13, 2021, 5:19 p.m. UTC | #1
On 8/13/21 9:59 AM, Tom Lendacky wrote:
> In prep for other protected virtualization technologies, introduce a
> generic helper function, prot_guest_has(), that can be used to check
> for specific protection attributes, like memory encryption. This is
> intended to eliminate having to add multiple technology-specific checks
> to the code (e.g. if (sev_active() || tdx_active())).
> 
> Reviewed-by: Joerg Roedel<jroedel@suse.de>
> Co-developed-by: Andi Kleen<ak@linux.intel.com>
> Signed-off-by: Andi Kleen<ak@linux.intel.com>
> Co-developed-by: Kuppuswamy Sathyanarayanan<sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Kuppuswamy Sathyanarayanan<sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Tom Lendacky<thomas.lendacky@amd.com>
> ---
>   arch/Kconfig                    |  3 +++
>   include/linux/protected_guest.h | 35 +++++++++++++++++++++++++++++++++
>   2 files changed, 38 insertions(+)
>   create mode 100644 include/linux/protected_guest.h

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Borislav Petkov Aug. 14, 2021, 6:32 p.m. UTC | #2
On Fri, Aug 13, 2021 at 11:59:21AM -0500, Tom Lendacky wrote:
> In prep for other protected virtualization technologies, introduce a
> generic helper function, prot_guest_has(), that can be used to check
> for specific protection attributes, like memory encryption. This is
> intended to eliminate having to add multiple technology-specific checks
> to the code (e.g. if (sev_active() || tdx_active())).
> 
> Reviewed-by: Joerg Roedel <jroedel@suse.de>
> Co-developed-by: Andi Kleen <ak@linux.intel.com>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/Kconfig                    |  3 +++
>  include/linux/protected_guest.h | 35 +++++++++++++++++++++++++++++++++
>  2 files changed, 38 insertions(+)
>  create mode 100644 include/linux/protected_guest.h
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 98db63496bab..bd4f60c581f1 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1231,6 +1231,9 @@ config RELR
>  config ARCH_HAS_MEM_ENCRYPT
>  	bool
>  
> +config ARCH_HAS_PROTECTED_GUEST
> +	bool
> +
>  config HAVE_SPARSE_SYSCALL_NR
>         bool
>         help
> diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
> new file mode 100644
> index 000000000000..43d4dde94793
> --- /dev/null
> +++ b/include/linux/protected_guest.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Protected Guest (and Host) Capability checks
> + *
> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> + *
> + * Author: Tom Lendacky <thomas.lendacky@amd.com>
> + */
> +
> +#ifndef _PROTECTED_GUEST_H
> +#define _PROTECTED_GUEST_H
> +
> +#ifndef __ASSEMBLY__
	   ^^^^^^^^^^^^^

Do you really need that guard? It builds fine without it too. Or
something coming later does need it...?
Tom Lendacky Aug. 14, 2021, 6:49 p.m. UTC | #3
On 8/14/21 1:32 PM, Borislav Petkov wrote:
> On Fri, Aug 13, 2021 at 11:59:21AM -0500, Tom Lendacky wrote:
>> diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
>> new file mode 100644
>> index 000000000000..43d4dde94793
>> --- /dev/null
>> +++ b/include/linux/protected_guest.h
>> @@ -0,0 +1,35 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Protected Guest (and Host) Capability checks
>> + *
>> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
>> + *
>> + * Author: Tom Lendacky <thomas.lendacky@amd.com>
>> + */
>> +
>> +#ifndef _PROTECTED_GUEST_H
>> +#define _PROTECTED_GUEST_H
>> +
>> +#ifndef __ASSEMBLY__
> 	   ^^^^^^^^^^^^^
> 
> Do you really need that guard? It builds fine without it too. Or
> something coming later does need it...?

No, I probably did it out of habit. I can remove it in the next version.

Thanks,
Tom

>
Christoph Hellwig Aug. 19, 2021, 9:46 a.m. UTC | #4
On Fri, Aug 13, 2021 at 11:59:21AM -0500, Tom Lendacky wrote:
> +#define PATTR_MEM_ENCRYPT		0	/* Encrypted memory */
> +#define PATTR_HOST_MEM_ENCRYPT		1	/* Host encrypted memory */
> +#define PATTR_GUEST_MEM_ENCRYPT		2	/* Guest encrypted memory */
> +#define PATTR_GUEST_PROT_STATE		3	/* Guest encrypted state */

Please write an actual detailed explanaton of what these mean, that
is what implications it has on the kernel.
Tom Lendacky Aug. 19, 2021, 4:39 p.m. UTC | #5
On 8/19/21 4:46 AM, Christoph Hellwig wrote:
> On Fri, Aug 13, 2021 at 11:59:21AM -0500, Tom Lendacky wrote:
>> +#define PATTR_MEM_ENCRYPT		0	/* Encrypted memory */
>> +#define PATTR_HOST_MEM_ENCRYPT		1	/* Host encrypted memory */
>> +#define PATTR_GUEST_MEM_ENCRYPT		2	/* Guest encrypted memory */
>> +#define PATTR_GUEST_PROT_STATE		3	/* Guest encrypted state */
> 
> Please write an actual detailed explanaton of what these mean, that
> is what implications it has on the kernel.

Will do.

Thanks,
Tom

>
diff mbox series

Patch

diff --git a/arch/Kconfig b/arch/Kconfig
index 98db63496bab..bd4f60c581f1 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1231,6 +1231,9 @@  config RELR
 config ARCH_HAS_MEM_ENCRYPT
 	bool
 
+config ARCH_HAS_PROTECTED_GUEST
+	bool
+
 config HAVE_SPARSE_SYSCALL_NR
        bool
        help
diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
new file mode 100644
index 000000000000..43d4dde94793
--- /dev/null
+++ b/include/linux/protected_guest.h
@@ -0,0 +1,35 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Protected Guest (and Host) Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ */
+
+#ifndef _PROTECTED_GUEST_H
+#define _PROTECTED_GUEST_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+
+#define PATTR_MEM_ENCRYPT		0	/* Encrypted memory */
+#define PATTR_HOST_MEM_ENCRYPT		1	/* Host encrypted memory */
+#define PATTR_GUEST_MEM_ENCRYPT		2	/* Guest encrypted memory */
+#define PATTR_GUEST_PROT_STATE		3	/* Guest encrypted state */
+
+#ifdef CONFIG_ARCH_HAS_PROTECTED_GUEST
+
+#include <asm/protected_guest.h>
+
+#else	/* !CONFIG_ARCH_HAS_PROTECTED_GUEST */
+
+static inline bool prot_guest_has(unsigned int attr) { return false; }
+
+#endif	/* CONFIG_ARCH_HAS_PROTECTED_GUEST */
+
+#endif	/* __ASSEMBLY__ */
+
+#endif	/* _PROTECTED_GUEST_H */