From 535f7ef2ab7dbfbcfe732ee7634faca21417a777 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 15 Sep 2020 12:15:04 -0700 Subject: KVM: VMX: Move IRQ invocation to assembly subroutine Move the asm blob that invokes the appropriate IRQ handler after VM-Exit into a proper subroutine. Unconditionally create a stack frame in the subroutine so that, as objtool sees things, the function has standard stack behavior. The dynamic stack adjustment makes using unwind hints problematic. Suggested-by: Josh Poimboeuf Cc: Uros Bizjak Signed-off-by: Sean Christopherson Message-Id: <20200915191505.10355-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmenter.S | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'arch/x86/kvm/vmx/vmenter.S') diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index 799db084a336..90ad7a6246e3 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -4,6 +4,7 @@ #include #include #include +#include #define WORD_SIZE (BITS_PER_LONG / 8) @@ -294,3 +295,36 @@ SYM_FUNC_START(vmread_error_trampoline) ret SYM_FUNC_END(vmread_error_trampoline) + +SYM_FUNC_START(vmx_do_interrupt_nmi_irqoff) + /* + * Unconditionally create a stack frame, getting the correct RSP on the + * stack (for x86-64) would take two instructions anyways, and RBP can + * be used to restore RSP to make objtool happy (see below). + */ + push %_ASM_BP + mov %_ASM_SP, %_ASM_BP + +#ifdef CONFIG_X86_64 + /* + * Align RSP to a 16-byte boundary (to emulate CPU behavior) before + * creating the synthetic interrupt stack frame for the IRQ/NMI. + */ + and $-16, %rsp + push $__KERNEL_DS + push %rbp +#endif + pushf + push $__KERNEL_CS + CALL_NOSPEC _ASM_ARG1 + + /* + * "Restore" RSP from RBP, even though IRET has already unwound RSP to + * the correct value. objtool doesn't know the callee will IRET and, + * 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 + ret +SYM_FUNC_END(vmx_do_interrupt_nmi_irqoff) -- cgit v1.2.3