diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2025-04-14 10:10:51 +0200 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-04-24 11:23:07 -0700 |
| commit | 798b9b1cb0e55c10fe761f42de5e28ecec8ef1f4 (patch) | |
| tree | ea2d4cd4d47c1fbc86e919a19e1a39b0d6274d59 | |
| parent | 17a2c62fbf1ea46f3ae32c601350488d2b6df730 (diff) | |
KVM: VMX: Use LEAVE in vmx_do_interrupt_irqoff()
Micro-optimize vmx_do_interrupt_irqoff() by substituting
MOV %RBP,%RSP; POP %RBP instruction sequence with equivalent
LEAVE instruction. GCC compiler does this by default for
a generic tuning and for all modern processors:
DEF_TUNE (X86_TUNE_USE_LEAVE, "use_leave",
m_386 | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_ZHAOXIN
| m_TREMONT | m_CORE_HYBRID | m_CORE_ATOM | m_GENERIC)
The new code also saves a couple of bytes, from:
27: 48 89 ec mov %rbp,%rsp
2a: 5d pop %rbp
to:
27: c9 leave
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20250414081131.97374-2-ubizjak@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/vmx/vmenter.S | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index f6986dee6f8c..0a6cf5bff2aa 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -59,8 +59,7 @@ * without the explicit restore, thinks the stack is getting walloped. * Using an unwind hint is problematic due to x86-64's dynamic alignment. */ - mov %_ASM_BP, %_ASM_SP - pop %_ASM_BP + leave RET .endm |