Re: [PATCH 01/11] mm: Introduce a function to check for virtualization protection features
On 8/11/21 9:53 AM, Kuppuswamy, Sathyanarayanan wrote: > On 7/27/21 3:26 PM, Tom Lendacky wrote: >> diff --git a/include/linux/protected_guest.h >> b/include/linux/protected_guest.h >> new file mode 100644 >> index ..f8ed7b72967b >> --- /dev/null >> +++ b/include/linux/protected_guest.h >> @@ -0,0 +1,32 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Protected Guest (and Host) Capability checks >> + * >> + * Copyright (C) 2021 Advanced Micro Devices, Inc. >> + * >> + * Author: Tom Lendacky >> + */ >> + >> +#ifndef _PROTECTED_GUEST_H >> +#define _PROTECTED_GUEST_H >> + >> +#ifndef __ASSEMBLY__ > > Can you include headers for bool type and false definition? Can do. Thanks, Tom > > --- a/include/linux/protected_guest.h > +++ b/include/linux/protected_guest.h > @@ -12,6 +12,9 @@ > > #ifndef __ASSEMBLY__ > > +#include > +#include > > Otherwise, I see following errors in multi-config auto testing. > > include/linux/protected_guest.h:40:15: error: unknown type name 'bool' > include/linux/protected_guest.h:40:63: error: 'false' undeclared (first > use in this functi >
Re: [PATCH 01/11] mm: Introduce a function to check for virtualization protection features
On 7/27/21 3:26 PM, Tom Lendacky wrote:
diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
new file mode 100644
index ..f8ed7b72967b
--- /dev/null
+++ b/include/linux/protected_guest.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Protected Guest (and Host) Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky
+ */
+
+#ifndef _PROTECTED_GUEST_H
+#define _PROTECTED_GUEST_H
+
+#ifndef __ASSEMBLY__
Can you include headers for bool type and false definition?
--- a/include/linux/protected_guest.h
+++ b/include/linux/protected_guest.h
@@ -12,6 +12,9 @@
#ifndef __ASSEMBLY__
+#include
+#include
Otherwise, I see following errors in multi-config auto testing.
include/linux/protected_guest.h:40:15: error: unknown type name 'bool'
include/linux/protected_guest.h:40:63: error: 'false' undeclared (first use in
this functi
+
+#define PATTR_MEM_ENCRYPT 0 /* Encrypted memory */
+#define PATTR_HOST_MEM_ENCRYPT 1 /* Host encrypted memory */
+#define PATTR_GUEST_MEM_ENCRYPT2 /* Guest encrypted
memory */
+#define PATTR_GUEST_PROT_STATE 3 /* Guest encrypted state */
+
+#ifdef CONFIG_ARCH_HAS_PROTECTED_GUEST
+
+#include
+
+#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 */
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
Re: [PATCH 01/11] mm: Introduce a function to check for virtualization protection features
On Tue, Jul 27, 2021 at 05:26:04PM -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())). > > Co-developed-by: Andi Kleen > Signed-off-by: Andi Kleen > Co-developed-by: Kuppuswamy Sathyanarayanan > > Signed-off-by: Kuppuswamy Sathyanarayanan > > Signed-off-by: Tom Lendacky Reviewed-by: Joerg Roedel
Re: [PATCH 01/11] mm: Introduce a function to check for virtualization protection features
On Wed, Jul 28, 2021 at 02:17:27PM +0100, Christoph Hellwig wrote: > So common checks obviously make sense, but I really hate the stupid > multiplexer. Having one well-documented helper per feature is much > easier to follow. We had that in x86 - it was called cpu_has_ where xxx is the feature bit. It didn't scale with the sheer amount of feature bits that kept getting added so we do cpu_feature_enabled(X86_FEATURE_XXX) now. The idea behind this is very similar - those protected guest flags will only grow in the couple of tens range - at least - so having a multiplexer is a lot simpler, I'd say, than having a couple of tens of helpers. And those PATTR flags should have good, readable names, btw. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
Re: [PATCH 01/11] mm: Introduce a function to check for virtualization protection features
On Tue, Jul 27, 2021 at 05:26:04PM -0500, Tom Lendacky via iommu 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())). So common checks obviously make sense, but I really hate the stupid multiplexer. Having one well-documented helper per feature is much easier to follow. > +#define PATTR_MEM_ENCRYPT0 /* 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 */ The kerneldoc comments on these individual helpers will give you plenty of space to properly document what they indicate and what a (potential) caller should do based on them. Something the above comments completely fail to.
[PATCH 01/11] mm: Introduce a function to check for virtualization protection features
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())).
Co-developed-by: Andi Kleen
Signed-off-by: Andi Kleen
Co-developed-by: Kuppuswamy Sathyanarayanan
Signed-off-by: Kuppuswamy Sathyanarayanan
Signed-off-by: Tom Lendacky
---
arch/Kconfig| 3 +++
include/linux/protected_guest.h | 32
2 files changed, 35 insertions(+)
create mode 100644 include/linux/protected_guest.h
diff --git a/arch/Kconfig b/arch/Kconfig
index 129df498a8e1..a47cf283f2ff 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 ..f8ed7b72967b
--- /dev/null
+++ b/include/linux/protected_guest.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Protected Guest (and Host) Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky
+ */
+
+#ifndef _PROTECTED_GUEST_H
+#define _PROTECTED_GUEST_H
+
+#ifndef __ASSEMBLY__
+
+#define PATTR_MEM_ENCRYPT 0 /* Encrypted memory */
+#define PATTR_HOST_MEM_ENCRYPT 1 /* Host encrypted memory */
+#define PATTR_GUEST_MEM_ENCRYPT2 /* Guest encrypted
memory */
+#define PATTR_GUEST_PROT_STATE 3 /* Guest encrypted state */
+
+#ifdef CONFIG_ARCH_HAS_PROTECTED_GUEST
+
+#include
+
+#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 */
--
2.32.0
