| Message ID | cbc875b1d2113225c2b44a2384d5b303d0453cf7.1627424774.git.thomas.lendacky@amd.com (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | Implement generic prot_guest_has() helper function | expand |
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_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 */ 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.
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_<xxx> 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.
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 <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> Reviewed-by: Joerg Roedel <jroedel@suse.de>
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 000000000000..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<thomas.lendacky@amd.com> > + */ > + > +#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 <linux/types.h> +#include <linux/stddef.h> 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_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 */
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 000000000000..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<thomas.lendacky@amd.com> >> + */ >> + >> +#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 <linux/types.h> > +#include <linux/stddef.h> > > 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 >
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 000000000000..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 <thomas.lendacky@amd.com> + */ + +#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_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 */