Commit a62fd5a7 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: VMX: Use RAX as the scratch register during vCPU-run 



...to prepare for making the sub-routine callable from C code.  That
means returning the result in RAX.  Since RAX will be used to return the
result, use it as the scratch register as well to make the code readable
and to document that the scratch register is more or less arbitrary.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ee2fc635

arch/x86/kvm/vmx/vmenter.S

+38 −38
Original line number Diff line number Diff line
@@ -103,31 +103,31 @@ ENTRY(__vmx_vcpu_run) 
	lea -WORD_SIZE(%_ASM_SP), %_ASM_ARG2

	call vmx_update_host_rsp



	/* Load @regs to RCX. */

	mov (%_ASM_SP), %_ASM_CX

	/* Load @regs to RAX. */

	mov (%_ASM_SP), %_ASM_AX



	/* Check if vmlaunch or vmresume is needed */

	cmpb $0, %bl



	/* Load guest registers.  Don't clobber flags. */

	mov VCPU_RAX(%_ASM_CX), %_ASM_AX

	mov VCPU_RBX(%_ASM_CX), %_ASM_BX

	mov VCPU_RDX(%_ASM_CX), %_ASM_DX

	mov VCPU_RSI(%_ASM_CX), %_ASM_SI

	mov VCPU_RDI(%_ASM_CX), %_ASM_DI

	mov VCPU_RBP(%_ASM_CX), %_ASM_BP

	mov VCPU_RBX(%_ASM_AX), %_ASM_BX

	mov VCPU_RCX(%_ASM_AX), %_ASM_CX

	mov VCPU_RDX(%_ASM_AX), %_ASM_DX

	mov VCPU_RSI(%_ASM_AX), %_ASM_SI

	mov VCPU_RDI(%_ASM_AX), %_ASM_DI

	mov VCPU_RBP(%_ASM_AX), %_ASM_BP

#ifdef CONFIG_X86_64

	mov VCPU_R8 (%_ASM_CX),  %r8

	mov VCPU_R9 (%_ASM_CX),  %r9

	mov VCPU_R10(%_ASM_CX), %r10

	mov VCPU_R11(%_ASM_CX), %r11

	mov VCPU_R12(%_ASM_CX), %r12

	mov VCPU_R13(%_ASM_CX), %r13

	mov VCPU_R14(%_ASM_CX), %r14

	mov VCPU_R15(%_ASM_CX), %r15

	mov VCPU_R8 (%_ASM_AX),  %r8

	mov VCPU_R9 (%_ASM_AX),  %r9

	mov VCPU_R10(%_ASM_AX), %r10

	mov VCPU_R11(%_ASM_AX), %r11

	mov VCPU_R12(%_ASM_AX), %r12

	mov VCPU_R13(%_ASM_AX), %r13

	mov VCPU_R14(%_ASM_AX), %r14

	mov VCPU_R15(%_ASM_AX), %r15

#endif

	/* Load guest RCX.  This kills the vmx_vcpu pointer! */

	mov VCPU_RCX(%_ASM_CX), %_ASM_CX

	/* Load guest RAX.  This kills the vmx_vcpu pointer! */

	mov VCPU_RAX(%_ASM_AX), %_ASM_AX



	/* Enter guest mode */

	call vmx_vmenter
@@ -135,29 +135,29 @@ ENTRY(__vmx_vcpu_run) 
	/* Jump on VM-Fail. */

	jbe 2f



	/* Temporarily save guest's RCX. */

	push %_ASM_CX

	/* Temporarily save guest's RAX. */

	push %_ASM_AX



	/* Reload @regs to RCX. */

	mov WORD_SIZE(%_ASM_SP), %_ASM_CX

	/* Reload @regs to RAX. */

	mov WORD_SIZE(%_ASM_SP), %_ASM_AX



	/* Save all guest registers, including RCX from the stack */

	mov %_ASM_AX,   VCPU_RAX(%_ASM_CX)

	mov %_ASM_BX,   VCPU_RBX(%_ASM_CX)

	__ASM_SIZE(pop) VCPU_RCX(%_ASM_CX)

	mov %_ASM_DX,   VCPU_RDX(%_ASM_CX)

	mov %_ASM_SI,   VCPU_RSI(%_ASM_CX)

	mov %_ASM_DI,   VCPU_RDI(%_ASM_CX)

	mov %_ASM_BP,   VCPU_RBP(%_ASM_CX)

	/* Save all guest registers, including RAX from the stack */

	__ASM_SIZE(pop) VCPU_RAX(%_ASM_AX)

	mov %_ASM_BX,   VCPU_RBX(%_ASM_AX)

	mov %_ASM_CX,   VCPU_RCX(%_ASM_AX)

	mov %_ASM_DX,   VCPU_RDX(%_ASM_AX)

	mov %_ASM_SI,   VCPU_RSI(%_ASM_AX)

	mov %_ASM_DI,   VCPU_RDI(%_ASM_AX)

	mov %_ASM_BP,   VCPU_RBP(%_ASM_AX)

#ifdef CONFIG_X86_64

	mov %r8,  VCPU_R8 (%_ASM_CX)

	mov %r9,  VCPU_R9 (%_ASM_CX)

	mov %r10, VCPU_R10(%_ASM_CX)

	mov %r11, VCPU_R11(%_ASM_CX)

	mov %r12, VCPU_R12(%_ASM_CX)

	mov %r13, VCPU_R13(%_ASM_CX)

	mov %r14, VCPU_R14(%_ASM_CX)

	mov %r15, VCPU_R15(%_ASM_CX)

	mov %r8,  VCPU_R8 (%_ASM_AX)

	mov %r9,  VCPU_R9 (%_ASM_AX)

	mov %r10, VCPU_R10(%_ASM_AX)

	mov %r11, VCPU_R11(%_ASM_AX)

	mov %r12, VCPU_R12(%_ASM_AX)

	mov %r13, VCPU_R13(%_ASM_AX)

	mov %r14, VCPU_R14(%_ASM_AX)

	mov %r15, VCPU_R15(%_ASM_AX)

#endif



	/* Clear EBX to indicate VM-Exit (as opposed to VM-Fail). */

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