linux-kernel - [PATCH 08/20] x86/tdx: Convert MMIO handling to use new TDVMCALL macros

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Date: Fri, 17 May 2024 17:19:26 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>,
	Dexuan Cui <decui@...rosoft.com>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>
Cc: linux-coco@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 08/20] x86/tdx: Convert MMIO handling to use new TDVMCALL macros

Use newly introduced TDVMCALL_0() and TDVMCALL_1() instead of
__tdx_hypercall() to handle MMIO emulation.

It cuts code bloat substantially:

Function                                     old     new   delta
tdx_handle_virt_exception                   1747    1383    -364

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 arch/x86/coco/tdx/tdx.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index c436cab355e0..df3e10d899b3 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -438,38 +438,34 @@ static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve)
 	return ve_instr_len(ve);
 }
 
-static bool mmio_read(int size, unsigned long addr, unsigned long *val)
+static bool mmio_read(int size, unsigned long gpa, u64 *val)
 {
-	struct tdx_module_args args = {
-		.r10 = TDX_HYPERCALL_STANDARD,
-		.r11 = hcall_func(EXIT_REASON_EPT_VIOLATION),
-		.r12 = size,
-		.r13 = EPT_READ,
-		.r14 = addr,
-		.r15 = *val,
-	};
+	bool ret;
+	u64 out;
 
-	if (__tdx_hypercall(&args))
-		return false;
+	ret = !TDVMCALL_1(hcall_func(EXIT_REASON_EPT_VIOLATION),
+			  size, EPT_READ, gpa, 0, out);
+	if (ret)
+		*val = out;
 
-	*val = args.r11;
-	return true;
+	return ret;
 }
 
-static bool mmio_write(int size, unsigned long addr, unsigned long val)
+static bool mmio_write(int size, u64 gpa, u64 val)
 {
-	return !_tdx_hypercall(hcall_func(EXIT_REASON_EPT_VIOLATION), size,
-			       EPT_WRITE, addr, val);
+	return !TDVMCALL_0(hcall_func(EXIT_REASON_EPT_VIOLATION),
+			 size, EPT_WRITE, gpa, val);
 }
 
 static int handle_mmio(struct pt_regs *regs, struct ve_info *ve)
 {
-	unsigned long *reg, val, vaddr;
+	unsigned long *reg, vaddr;
 	char buffer[MAX_INSN_SIZE];
 	enum insn_mmio_type mmio;
 	struct insn insn = {};
 	int size, extend_size;
 	u8 extend_val = 0;
+	u64 val;
 
 	/* Only in-kernel MMIO is supported */
 	if (WARN_ON_ONCE(user_mode(regs)))
-- 
2.43.0