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authorKai Huang <kai.huang@intel.com>2023-08-15 14:02:00 +0300
committerDave Hansen <dave.hansen@linux.intel.com>2023-09-12 02:33:51 +0300
commit12f34ed8622aafd3bbd9d8aa4550dcb7016ea1e6 (patch)
treede9b82710da67007a27f2e54c95c88218bb63601 /arch/x86/coco
parent57a420bb8186d1d0178b857e5dd5026093641654 (diff)
downloadlinux-12f34ed8622aafd3bbd9d8aa4550dcb7016ea1e6.tar.xz
x86/tdx: Extend TDX_MODULE_CALL to support more TDCALL/SEAMCALL leafs
The TDX guest live migration support (TDX 1.5) adds new TDCALL/SEAMCALL leaf functions. Those new TDCALLs/SEAMCALLs take additional registers for input (R10-R13) and output (R12-R13). TDG.SERVTD.RD is an example. Also, the current TDX_MODULE_CALL doesn't aim to handle TDH.VP.ENTER SEAMCALL, which monitors the TDG.VP.VMCALL in input/output registers when it returns in case of VMCALL from TDX guest. With those new TDCALLs/SEAMCALLs and the TDH.VP.ENTER covered, the TDX_MODULE_CALL macro basically needs to handle the same input/output registers as the TDX_HYPERCALL does. And as a result, they also share similar logic in the assembly, thus should be unified to use one common assembly. Extend the TDX_MODULE_CALL asm to support the new TDCALLs/SEAMCALLs and also the TDH.VP.ENTER SEAMCALL. Eventually it will be unified with the TDX_HYPERCALL. The new input/output registers fit with the "callee-saved" registers in the x86 calling convention. Add a new "saved" parameter to support those new TDCALLs/SEAMCALLs and TDH.VP.ENTER and keep the existing TDCALLs/SEAMCALLs minimally impacted. For TDH.VP.ENTER, after it returns the registers shared by the guest contain guest's values. Explicitly clear them to prevent speculative use of guest's values. Note most TDX live migration related SEAMCALLs may also clobber AVX* state ("AVX, AVX2 and AVX512 state: may be reset to the architectural INIT state" -- see TDH.EXPORT.MEM for example). And TDH.VP.ENTER also clobbers XMM0-XMM15 when the corresponding bit is set in RCX. Don't handle them in the TDX_MODULE_CALL macro but let the caller save and restore when needed. This is basically based on Peter's code. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/all/d4785de7c392f7c5684407f6c24a73b92148ec49.1692096753.git.kai.huang%40intel.com
Diffstat (limited to 'arch/x86/coco')
-rw-r--r--arch/x86/coco/tdx/tdcall.S4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S
index 56b9cd32895e..faf731d2b66a 100644
--- a/arch/x86/coco/tdx/tdcall.S
+++ b/arch/x86/coco/tdx/tdcall.S
@@ -48,6 +48,8 @@
* @fn (RDI) - TDCALL Leaf ID, moved to RAX
* @args (RSI) - struct tdx_module_args for input
*
+ * Only RCX/RDX/R8-R11 are used as input registers.
+ *
* Return status of TDCALL via RAX.
*/
SYM_FUNC_START(__tdcall)
@@ -64,6 +66,8 @@ SYM_FUNC_END(__tdcall)
* @fn (RDI) - TDCALL Leaf ID, moved to RAX
* @args (RSI) - struct tdx_module_args for input and output
*
+ * Only RCX/RDX/R8-R11 are used as input/output registers.
+ *
* Return status of TDCALL via RAX.
*/
SYM_FUNC_START(__tdcall_ret)