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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 /include/linux/cc_platform.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 'include/linux/cc_platform.h')
| -rw-r--r-- | include/linux/cc_platform.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h index a075b70b9a70..efd8205282da 100644 --- a/include/linux/cc_platform.h +++ b/include/linux/cc_platform.h @@ -61,6 +61,17 @@ enum cc_attr { * Examples include SEV-ES. */ CC_ATTR_GUEST_STATE_ENCRYPT, + + /** + * @CC_ATTR_GUEST_UNROLL_STRING_IO: String I/O is implemented with + * IN/OUT instructions + * + * The platform/OS is running as a guest/virtual machine and uses + * IN/OUT instructions in place of string I/O. + * + * Examples include TDX guest & SEV. + */ + CC_ATTR_GUEST_UNROLL_STRING_IO, }; #ifdef CONFIG_ARCH_HAS_CC_PLATFORM |