[PATCH 3/8] KVM: SVM: Drop 32-bit "support" from __svm_sev_es_vcpu_run()

From: Sean Christopherson
Date: Fri Feb 23 2024 - 15:45:44 EST


Drop 32-bit "support" from __svm_sev_es_vcpu_run(), as SEV/SEV-ES firmly
64-bit only. The "support" was purely the result of bad copy+paste from
__svm_vcpu_run(), which in turn was slightly less bad copy+paste from
__vmx_vcpu_run().

Opportunistically convert to unadulterated register accesses so that it's
easier (but still not easy) to follow which registers hold what arguments,
and when.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/svm/vmenter.S | 44 +++++++++++---------------------------
1 file changed, 13 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 7ee363d7517c..0026b4a56d25 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -298,17 +298,12 @@ SYM_FUNC_END(__svm_vcpu_run)
* @spec_ctrl_intercepted: bool
*/
SYM_FUNC_START(__svm_sev_es_vcpu_run)
- push %_ASM_BP
-#ifdef CONFIG_X86_64
+ push %rbp
push %r15
push %r14
push %r13
push %r12
-#else
- push %edi
- push %esi
-#endif
- push %_ASM_BX
+ push %rbx

/*
* Save variables needed after vmexit on the stack, in inverse
@@ -316,39 +311,31 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
*/

/* Accessed directly from the stack in RESTORE_HOST_SPEC_CTRL. */
- push %_ASM_ARG2
+ push %rsi

/* Save @svm. */
- push %_ASM_ARG1
-
-.ifnc _ASM_ARG1, _ASM_DI
- /*
- * Stash @svm in RDI early. On 32-bit, arguments are in RAX, RCX
- * and RDX which are clobbered by RESTORE_GUEST_SPEC_CTRL.
- */
- mov %_ASM_ARG1, %_ASM_DI
-.endif
+ push %rdi

/* Clobbers RAX, RCX, RDX. */
RESTORE_GUEST_SPEC_CTRL

/* Get svm->current_vmcb->pa into RAX. */
- mov SVM_current_vmcb(%_ASM_DI), %_ASM_AX
- mov KVM_VMCB_pa(%_ASM_AX), %_ASM_AX
+ mov SVM_current_vmcb(%rdi), %rax
+ mov KVM_VMCB_pa(%rax), %rax

/* Enter guest mode */
sti

-1: vmrun %_ASM_AX
+1: vmrun %rax

2: cli

/* Pop @svm to RDI, guest registers have been saved already. */
- pop %_ASM_DI
+ pop %rdi

#ifdef CONFIG_RETPOLINE
/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
- FILL_RETURN_BUFFER %_ASM_AX, RSB_CLEAR_LOOPS, X86_FEATURE_RETPOLINE
+ FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_FEATURE_RETPOLINE
#endif

/* Clobbers RAX, RCX, RDX. */
@@ -364,26 +351,21 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
UNTRAIN_RET_VM

/* "Pop" @spec_ctrl_intercepted. */
- pop %_ASM_BX
+ pop %rbx

- pop %_ASM_BX
+ pop %rbx

-#ifdef CONFIG_X86_64
pop %r12
pop %r13
pop %r14
pop %r15
-#else
- pop %esi
- pop %edi
-#endif
- pop %_ASM_BP
+ pop %rbp
RET

RESTORE_GUEST_SPEC_CTRL_BODY
RESTORE_HOST_SPEC_CTRL_BODY

-3: cmpb $0, _ASM_RIP(kvm_rebooting)
+3: cmpb $0, kvm_rebooting(%rip)
jne 2b
ud2

--
2.44.0.rc0.258.g7320e95886-goog