[tip: x86/asm] KVM: VMX: Use named operands in inline asm

From: tip-bot2 for Josh Poimboeuf
Date: Tue Mar 04 2025 - 05:37:54 EST


The following commit has been merged into the x86/asm branch of tip:

Commit-ID: e1c49eaee52384ec9e3734138b3929a35b64e0c3
Gitweb: https://git.kernel.org/tip/e1c49eaee52384ec9e3734138b3929a35b64e0c3
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Sun, 02 Mar 2025 17:20:59 -08:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 04 Mar 2025 11:21:39 +01:00

KVM: VMX: Use named operands in inline asm

Convert the non-asm-goto version of the inline asm in __vmcs_readl() to
use named operands, similar to its asm-goto version.

Do this in preparation of changing the ASM_CALL_CONSTRAINT primitive.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
arch/x86/kvm/vmx/vmx_ops.h | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx_ops.h b/arch/x86/kvm/vmx/vmx_ops.h
index 633c87e..9667757 100644
--- a/arch/x86/kvm/vmx/vmx_ops.h
+++ b/arch/x86/kvm/vmx/vmx_ops.h
@@ -118,7 +118,7 @@ do_exception:

#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */

- asm volatile("1: vmread %2, %1\n\t"
+ asm volatile("1: vmread %[field], %[output]\n\t"
".byte 0x3e\n\t" /* branch taken hint */
"ja 3f\n\t"

@@ -127,24 +127,26 @@ do_exception:
* @field, and bounce through the trampoline to preserve
* volatile registers.
*/
- "xorl %k1, %k1\n\t"
+ "xorl %k[output], %k[output]\n\t"
"2:\n\t"
- "push %1\n\t"
- "push %2\n\t"
+ "push %[output]\n\t"
+ "push %[field]\n\t"
"call vmread_error_trampoline\n\t"

/*
* Unwind the stack. Note, the trampoline zeros out the
* memory for @fault so that the result is '0' on error.
*/
- "pop %2\n\t"
- "pop %1\n\t"
+ "pop %[field]\n\t"
+ "pop %[output]\n\t"
"3:\n\t"

/* VMREAD faulted. As above, except push '1' for @fault. */
- _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_ONE_REG, %1)
+ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_ONE_REG, %[output])

- : ASM_CALL_CONSTRAINT, "=&r"(value) : "r"(field) : "cc");
+ : ASM_CALL_CONSTRAINT, [output] "=&r" (value)
+ : [field] "r" (field)
+ : "cc");
return value;

#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */