linux-kernel - [tip: x86/tdx] x86/tdx: Wrap exit reason with hcall

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Date:   Tue, 23 May 2023 14:14:59 -0000
From:   "tip-bot2 for Nikolay Borisov" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Nikolay Borisov <nik.borisov@...e.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/tdx] x86/tdx: Wrap exit reason with hcall_func()

The following commit has been merged into the x86/tdx branch of tip:

Commit-ID:     122333d6bd229af279cdb35d1b874b71b3b9ccfb
Gitweb:        https://git.kernel.org/tip/122333d6bd229af279cdb35d1b874b71b3b9ccfb
Author:        Nikolay Borisov <nik.borisov@...e.com>
AuthorDate:    Fri, 05 May 2023 15:03:32 +03:00
Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Tue, 23 May 2023 07:01:45 -07:00

x86/tdx: Wrap exit reason with hcall_func()

TDX reuses VMEXIT "reasons" in its guest->host hypercall ABI.  This is
confusing because there might not be a VMEXIT involved at *all*.
These instances are supposed to document situation and reduce confusion
by wrapping VMEXIT reasons with hcall_func().

The decompression code does not follow this convention.

Unify the TDX decompression code with the other TDX use of VMEXIT reasons.
No functional changes.

Signed-off-by: Nikolay Borisov <nik.borisov@...e.com>
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Link: https://lore.kernel.org/all/20230505120332.1429957-1-nik.borisov%40suse.com
---
 arch/x86/boot/compressed/tdx.c    |  4 ++--
 arch/x86/coco/tdx/tdx.c           | 11 -----------
 arch/x86/include/asm/shared/tdx.h | 11 +++++++++++
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c
index 2d81d3c..8841b94 100644
--- a/arch/x86/boot/compressed/tdx.c
+++ b/arch/x86/boot/compressed/tdx.c
@@ -20,7 +20,7 @@ static inline unsigned int tdx_io_in(int size, u16 port)
 {
 	struct tdx_hypercall_args args = {
 		.r10 = TDX_HYPERCALL_STANDARD,
-		.r11 = EXIT_REASON_IO_INSTRUCTION,
+		.r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION),
 		.r12 = size,
 		.r13 = 0,
 		.r14 = port,
@@ -36,7 +36,7 @@ static inline void tdx_io_out(int size, u16 port, u32 value)
 {
 	struct tdx_hypercall_args args = {
 		.r10 = TDX_HYPERCALL_STANDARD,
-		.r11 = EXIT_REASON_IO_INSTRUCTION,
+		.r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION),
 		.r12 = size,
 		.r13 = 1,
 		.r14 = port,
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index e146b59..15569bd 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -76,17 +76,6 @@ noinstr void __tdx_hypercall_failed(void)
 	panic("TDVMCALL failed. TDX module bug?");
 }
 
-/*
- * The TDG.VP.VMCALL-Instruction-execution sub-functions are defined
- * independently from but are currently matched 1:1 with VMX EXIT_REASONs.
- * Reusing the KVM EXIT_REASON macros makes it easier to connect the host and
- * guest sides of these calls.
- */
-static __always_inline u64 hcall_func(u64 exit_reason)
-{
-	return exit_reason;
-}
-
 #ifdef CONFIG_KVM_GUEST
 long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2,
 		       unsigned long p3, unsigned long p4)
diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index 2631e01..b415a24 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h
@@ -40,5 +40,16 @@ u64 __tdx_hypercall_ret(struct tdx_hypercall_args *args);
 /* Called from __tdx_hypercall() for unrecoverable failure */
 void __tdx_hypercall_failed(void);
 
+/*
+ * The TDG.VP.VMCALL-Instruction-execution sub-functions are defined
+ * independently from but are currently matched 1:1 with VMX EXIT_REASONs.
+ * Reusing the KVM EXIT_REASON macros makes it easier to connect the host and
+ * guest sides of these calls.
+ */
+static __always_inline u64 hcall_func(u64 exit_reason)
+{
+        return exit_reason;
+}
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASM_X86_SHARED_TDX_H */