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| author | Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> | 2021-12-06 16:55:03 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-12-08 18:49:42 +0300 |
| commit | 8260b9820f7050461b8969305bbd8cb5654f0c74 (patch) | |
| tree | 81ab83711298a1e04d4b819ce783a7393b31541c /arch/x86/include/asm/io.h | |
| parent | 75cc9a84c9eb36e436e3fcee5158fe31d1dfd78f (diff) | |
| download | linux-8260b9820f7050461b8969305bbd8cb5654f0c74.tar.xz | |
x86/sev: Use CC_ATTR attribute to generalize string I/O unroll
INS/OUTS are not supported in TDX guests and cause #UD. Kernel has to
avoid them when running in TDX guest. To support existing usage, string
I/O operations are unrolled using IN/OUT instructions.
AMD SEV platform implements this support by adding unroll
logic in ins#bwl()/outs#bwl() macros with SEV-specific checks.
Since TDX VM guests will also need similar support, use
CC_ATTR_GUEST_UNROLL_STRING_IO and generic cc_platform_has() API to
implement it.
String I/O helpers were the last users of sev_key_active() interface and
sev_enable_key static key. Remove them.
[ bp: Move comment too and do not delete it. ]
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211206135505.75045-2-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/include/asm/io.h')
| -rw-r--r-- | arch/x86/include/asm/io.h | 20 |
1 files changed, 3 insertions, 17 deletions
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 5c6a4af0b911..f6d91ecb8026 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -40,6 +40,7 @@ #include <linux/string.h> #include <linux/compiler.h> +#include <linux/cc_platform.h> #include <asm/page.h> #include <asm/early_ioremap.h> #include <asm/pgtable_types.h> @@ -256,21 +257,6 @@ static inline void slow_down_io(void) #endif -#ifdef CONFIG_AMD_MEM_ENCRYPT -#include <linux/jump_label.h> - -extern struct static_key_false sev_enable_key; -static inline bool sev_key_active(void) -{ - return static_branch_unlikely(&sev_enable_key); -} - -#else /* !CONFIG_AMD_MEM_ENCRYPT */ - -static inline bool sev_key_active(void) { return false; } - -#endif /* CONFIG_AMD_MEM_ENCRYPT */ - #define BUILDIO(bwl, bw, type) \ static inline void out##bwl(unsigned type value, int port) \ { \ @@ -301,7 +287,7 @@ static inline unsigned type in##bwl##_p(int port) \ \ static inline void outs##bwl(int port, const void *addr, unsigned long count) \ { \ - if (sev_key_active()) { \ + if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { \ unsigned type *value = (unsigned type *)addr; \ while (count) { \ out##bwl(*value, port); \ @@ -317,7 +303,7 @@ static inline void outs##bwl(int port, const void *addr, unsigned long count) \ \ static inline void ins##bwl(int port, void *addr, unsigned long count) \ { \ - if (sev_key_active()) { \ + if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { \ unsigned type *value = (unsigned type *)addr; \ while (count) { \ *value = in##bwl(port); \ |