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

Kirill A. Shutemov
2024-05-17T14:20:03Z

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@linux.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