diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2026-01-14 22:18:15 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2026-01-15 11:44:29 +0100 |
| commit | 31911d3c394d6556a67ff63cf0093049ef6dcdd7 (patch) | |
| tree | 023699fe35083bdd83395da2a4e0af73a14cded5 | |
| parent | baea32b242be8ff857cc27b910c6c325c24a7247 (diff) | |
x86/paravirt: Use XOR r32,r32 to clear register in pv_vcpu_is_preempted()
x86_64 zero extends 32bit operations, so for 64bit operands, XOR r32,r32 is
functionally equal to XOR r64,r64, but avoids a REX prefix byte when legacy
registers are used.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Alexey Makhalov <alexey.makhalov@broadcom.com>
Link: https://patch.msgid.link/20260114211948.74774-2-ubizjak@gmail.com
| -rw-r--r-- | arch/x86/include/asm/paravirt-spinlock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/paravirt-spinlock.h b/arch/x86/include/asm/paravirt-spinlock.h index 458b888aba84..7beffcb08ed6 100644 --- a/arch/x86/include/asm/paravirt-spinlock.h +++ b/arch/x86/include/asm/paravirt-spinlock.h @@ -45,7 +45,7 @@ static __always_inline void pv_queued_spin_unlock(struct qspinlock *lock) static __always_inline bool pv_vcpu_is_preempted(long cpu) { return PVOP_ALT_CALLEE1(bool, pv_ops_lock, vcpu_is_preempted, cpu, - "xor %%" _ASM_AX ", %%" _ASM_AX, + "xor %%eax, %%eax", ALT_NOT(X86_FEATURE_VCPUPREEMPT)); } |