Commit 3b895ef4 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: VMX: Preserve callee-save registers in vCPU-run asm sub-routine 



...to make it callable from C code.

Note that because KVM chooses to be ultra paranoid about guest register
values, all callee-save registers are still cleared after VM-Exit even
though the host's values are now reloaded from the stack.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e75c3c3a

arch/x86/kvm/vmx/vmenter.S

+21 −0
Original line number Diff line number Diff line
@@ -92,6 +92,16 @@ ENDPROC(vmx_vmexit) 
ENTRY(__vmx_vcpu_run)

	push %_ASM_BP

	mov  %_ASM_SP, %_ASM_BP

#ifdef CONFIG_X86_64

	push %r15

	push %r14

	push %r13

	push %r12

#else

	push %edi

	push %esi

#endif

	push %_ASM_BX



	/*

	 * Save @regs, _ASM_ARG2 may be modified by vmx_update_host_rsp() and
@@ -195,6 +205,17 @@ ENTRY(__vmx_vcpu_run) 


	/* "POP" @regs. */

	add $WORD_SIZE, %_ASM_SP

	pop %_ASM_BX



#ifdef CONFIG_X86_64

	pop %r12

	pop %r13

	pop %r14

	pop %r15

#else

	pop %esi

	pop %edi

#endif

	pop %_ASM_BP

	ret

arch/x86/kvm/vmx/vmx.c

+1 −4
Original line number Diff line number Diff line
@@ -6456,10 +6456,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) 
#endif

	      : "cc", "memory"

#ifdef CONFIG_X86_64

		, "rbx", "rcx"

		, "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"

#else

		, "ebx", "edi", "esi"

		, "rcx", "r8", "r9", "r10", "r11"

#endif

	      );