Re: [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has()
From: Borislav Petkov <bp@alien8.de>
Date: 2021-08-14 19:08:41
Also in:
amd-gfx, dri-devel, kexec, kvm, linux-efi, linux-fsdevel, linux-iommu, linux-s390, lkml, platform-driver-x86
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
On Fri, Aug 13, 2021 at 11:59:22AM -0500, Tom Lendacky wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/include/asm/protected_guest.h b/arch/x86/include/asm/protected_guest.h new file mode 100644 index 000000000000..51e4eefd9542 --- /dev/null +++ b/arch/x86/include/asm/protected_guest.h@@ -0,0 +1,29 @@ +/* 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 _X86_PROTECTED_GUEST_H +#define _X86_PROTECTED_GUEST_H + +#include <linux/mem_encrypt.h> + +#ifndef __ASSEMBLY__ + +static inline bool prot_guest_has(unsigned int attr) +{ +#ifdef CONFIG_AMD_MEM_ENCRYPT + if (sme_me_mask) + return amd_prot_guest_has(attr); +#endif + + return false; +} + +#endif /* __ASSEMBLY__ */ + +#endif /* _X86_PROTECTED_GUEST_H */
I think this can be simplified more, diff ontop below: - no need for the ifdeffery as amd_prot_guest_has() has versions for both when CONFIG_AMD_MEM_ENCRYPT is set or not. - the sme_me_mask check is pushed there too. - and since this is vendor-specific, I'm checking the vendor bit. Yeah, yeah, cross-vendor but I don't really believe that. ---
diff --git a/arch/x86/include/asm/protected_guest.h b/arch/x86/include/asm/protected_guest.h
index 51e4eefd9542..8541c76d5da4 100644
--- a/arch/x86/include/asm/protected_guest.h
+++ b/arch/x86/include/asm/protected_guest.h@@ -12,18 +12,13 @@ #include <linux/mem_encrypt.h> -#ifndef __ASSEMBLY__ - static inline bool prot_guest_has(unsigned int attr) { -#ifdef CONFIG_AMD_MEM_ENCRYPT - if (sme_me_mask) + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) return amd_prot_guest_has(attr); -#endif return false; } -#endif /* __ASSEMBLY__ */ - #endif /* _X86_PROTECTED_GUEST_H */
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index edc67ddf065d..5a0442a6f072 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c@@ -392,6 +392,9 @@ bool noinstr sev_es_active(void) bool amd_prot_guest_has(unsigned int attr) { + if (!sme_me_mask) + return false; + switch (attr) { case PATTR_MEM_ENCRYPT: return sme_me_mask != 0;
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette