[PATCH 12/20] x86/tdx: Rewrite tdx_kvm_hypercall() without __tdx_hypercall()

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

tdx_kvm_hypercall() issues KVM hypercall. Rewrite it without using
__tdx_hypercall(). Use tdvmcall_trampoline() instead.

It cuts code bloat substantially:

Function old new delta
tdx_kvm_hypercall 160 53 -107

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/coco/tdx/tdx.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index b7299e668564..e7ffe1cd6d32 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -49,15 +49,15 @@ noinstr void __noreturn __tdx_hypercall_failed(void)
long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2,
unsigned long p3, unsigned long p4)
{
- struct tdx_module_args args = {
- .r10 = nr,
- .r11 = p1,
- .r12 = p2,
- .r13 = p3,
- .r14 = p4,
- };
+ long ret;

- return __tdx_hypercall(&args);
+ asm("call tdvmcall_trampoline\n\t"
+ "movq %%r10, %0\n\t"
+ : "=r" (ret)
+ : "a" (nr), "b" (p1), "D" (p2), "S"(p3), "d"(p4), "c" (0)
+ : "r12", "r13", "r14", "r15");
+
+ return ret;
}
EXPORT_SYMBOL_GPL(tdx_kvm_hypercall);
#endif
--
2.43.0