linux-kernel - [PATCH v13 05/22] x86/virt/tdx: Handle SEAMCALL no entropy error in common code

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Message-ID: <c945c9a8db98b7a304c404a7ef18aa2f7770ffaf.1692962263.git.kai.huang@intel.com>
Date:   Sat, 26 Aug 2023 00:14:24 +1200
From:   Kai Huang <kai.huang@...el.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     x86@...nel.org, dave.hansen@...el.com,
        kirill.shutemov@...ux.intel.com, tony.luck@...el.com,
        peterz@...radead.org, tglx@...utronix.de, bp@...en8.de,
        mingo@...hat.com, hpa@...or.com, seanjc@...gle.com,
        pbonzini@...hat.com, david@...hat.com, dan.j.williams@...el.com,
        rafael.j.wysocki@...el.com, ashok.raj@...el.com,
        reinette.chatre@...el.com, len.brown@...el.com, ak@...ux.intel.com,
        isaku.yamahata@...el.com, ying.huang@...el.com, chao.gao@...el.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com, nik.borisov@...e.com,
        bagasdotme@...il.com, sagis@...gle.com, imammedo@...hat.com,
        kai.huang@...el.com
Subject: [PATCH v13 05/22] x86/virt/tdx: Handle SEAMCALL no entropy error in common code

Some SEAMCALLs use the RDRAND hardware and can fail for the same reasons
as RDRAND.  Use the kernel RDRAND retry logic for them.

There are three __seamcall*() variants.  Add a macro to do the SEAMCALL
retry in the common code and define a wrapper for each __seamcall*()
variant.

Signed-off-by: Kai Huang <kai.huang@...el.com>
---

v12 -> v13:
 - New implementation due to TDCALL assembly series.

---
 arch/x86/include/asm/tdx.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index a252328734c7..cfae8b31a2e9 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -24,6 +24,11 @@
 #define TDX_SEAMCALL_GP			(TDX_SW_ERROR | X86_TRAP_GP)
 #define TDX_SEAMCALL_UD			(TDX_SW_ERROR | X86_TRAP_UD)
 
+/*
+ * TDX module SEAMCALL leaf function error codes
+ */
+#define TDX_RND_NO_ENTROPY	0x8000020300000000ULL
+
 #ifndef __ASSEMBLY__
 
 /*
@@ -82,6 +87,28 @@ u64 __seamcall(u64 fn, struct tdx_module_args *args);
 u64 __seamcall_ret(u64 fn, struct tdx_module_args *args);
 u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args);
 
+#include <asm/archrandom.h>
+
+#define SEAMCALL_NO_ENTROPY_RETRY(__seamcall_func, __fn, __args)	\
+({									\
+	int ___retry = RDRAND_RETRY_LOOPS;				\
+	u64 ___sret;							\
+									\
+	do {								\
+		___sret = __seamcall_func((__fn), (__args));		\
+	} while (___sret == TDX_RND_NO_ENTROPY && --___retry);		\
+	___sret;							\
+})
+
+#define seamcall(__fn, __args)						\
+	SEAMCALL_NO_ENTROPY_RETRY(__seamcall, (__fn), (__args))
+
+#define seamcall_ret(__fn, __args)					\
+	SEAMCALL_NO_ENTROPY_RETRY(__seamcall_ret, (__fn), (__args))
+
+#define seamcall_saved_ret(__fn, __args)				\
+	SEAMCALL_NO_ENTROPY_RETRY(__seamcall_saved_ret, (__fn), (__args))
+
 bool platform_tdx_enabled(void);
 #else
 static inline bool platform_tdx_enabled(void) { return false; }
-- 
2.41.0