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x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn

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Unlike CALL instruction, VMMCALL does not push to the stack, so it's
OK to allow the compiler to insert it before the frame pointer gets
set up by the containing function. ASM_CALL_CONSTRAINT is for CALLs
that must be inserted after the frame pointer is set up, so it is
over-constraining here and can be removed.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Uros Bizjak 2025-11-21 15:14:11 +01:00 committed by Wei Liu
parent 834ef6aa09
commit 885e78d71f
1 changed files with 1 additions and 1 deletions
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2
arch/x86/hyperv/ivm.c
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@ -392,7 +392,7 @@ u64 hv_snp_hypercall(u64 control, u64 param1, u64 param2)
register u64 __r8 asm("r8") = param2;
asm volatile("vmmcall"
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
: "=a" (hv_status),
"+c" (control), "+d" (param1), "+r" (__r8)
: : "cc", "memory", "r9", "r10", "r11");