Re: [kvm-unit-tests PATCH v3 3/3] x86/emulator: Add some tests for far jmp instruction emulation

[Sean Christopherson <seanjc@google.com>]

On Thu, Feb 10, 2022, Hou Wenlong wrote:
> @@ -76,6 +96,17 @@ static struct far_xfer_test far_ret_test = {
>  		     : "eax", "memory");	\
>  })
>  
> +#define TEST_FAR_JMP_ASM(seg, prefix)		\
> +({						\
> +	*(uint16_t *)(&fep_jmp_buf[1]) = seg;	\
> +	asm volatile("lea 1f(%%rip), %%rax\n\t" \
> +		     "movq $1f, (%[mem])\n\t"	\
> +		      prefix "rex64 ljmp *(%[mem])\n\t"\
> +		     "1:"			\
> +		     : : [mem]"r"(fep_jmp_buf_ptr)\
> +		     : "eax", "memory");	\

Align the backslashes for a given macro, even though it means the two TEST_FAR_*_ASM
macros won't share alignment.  This needs an -fPIC tweak for the movq too, but this
one is easy since RAX already holds what we want.

With the below fixup...

Reviewed-and-tested-by: Sean Christopherson <seanjc@google.com>

---
 x86/emulator.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/x86/emulator.c b/x86/emulator.c
index 22a5c9d..56a263e 100644
--- a/x86/emulator.c
+++ b/x86/emulator.c
@@ -97,15 +97,15 @@ static unsigned long *fep_jmp_buf_ptr = &fep_jmp_buf[0];
 		     : "eax", "memory");	\
 })

-#define TEST_FAR_JMP_ASM(seg, prefix)		\
-({						\
-	*(uint16_t *)(&fep_jmp_buf[1]) = seg;	\
-	asm volatile("lea 1f(%%rip), %%rax\n\t" \
-		     "movq $1f, (%[mem])\n\t"	\
-		      prefix "rex64 ljmp *(%[mem])\n\t"\
-		     "1:"			\
-		     : : [mem]"r"(fep_jmp_buf_ptr)\
-		     : "eax", "memory");	\
+#define TEST_FAR_JMP_ASM(seg, prefix)			\
+({							\
+	*(uint16_t *)(&fep_jmp_buf[1]) = seg;		\
+	asm volatile("lea 1f(%%rip), %%rax\n\t"		\
+		     "movq %%rax, (%[mem])\n\t"		\
+		      prefix "rex64 ljmp *(%[mem])\n\t"	\
+		     "1:"				\
+		     : : [mem]"r"(fep_jmp_buf_ptr)	\
+		     : "eax", "memory");		\
 })

 struct regs {

base-commit: 6bd9c4b6a79ed51c0e3e6a997654f4a9feb9c377
--