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From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: jmattson@google.com, seanjc@google.com, jpoimboe@kernel.org
Subject: [PATCH 2/7] KVM: VMX: more cleanups to __vmx_vcpu_run
Date: Fri, 28 Oct 2022 19:07:18 -0400	[thread overview]
Message-ID: <20221028230723.3254250-3-pbonzini@redhat.com> (raw)
In-Reply-To: <20221028230723.3254250-1-pbonzini@redhat.com>

Slightly improve register allocation, loading vmx only once
before vmlaunch/vmresume.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/vmx/vmenter.S | 40 +++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index 1362fe5859f9..0aea6b348a96 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -81,13 +81,12 @@ SYM_FUNC_START(__vmx_vcpu_run)
 	 * there must not be any returns or indirect branches between this code
 	 * and vmentry.
 	 */
-	movl VMX_spec_ctrl(%_ASM_DI), %edi
+	movl VMX_spec_ctrl(%_ASM_DI), %eax
 	movl PER_CPU_VAR(x86_spec_ctrl_current), %esi
-	cmp %edi, %esi
+	cmp %eax, %esi
 	je .Lspec_ctrl_done
 	mov $MSR_IA32_SPEC_CTRL, %ecx
 	xor %edx, %edx
-	mov %edi, %eax
 	wrmsr
 
 .Lspec_ctrl_done:
@@ -97,31 +96,28 @@ SYM_FUNC_START(__vmx_vcpu_run)
 	 * an LFENCE to stop speculation from skipping the wrmsr.
 	 */
 
-	/* Load @vmx to RAX. */
-	mov WORD_SIZE(%_ASM_SP), %_ASM_AX
-
 	/* Check if vmlaunch or vmresume is needed */
 	testb $VMX_RUN_VMRESUME, %bl
 
 	/* Load guest registers.  Don't clobber flags. */
-	mov VCPU_RCX(%_ASM_AX), %_ASM_CX
-	mov VCPU_RDX(%_ASM_AX), %_ASM_DX
-	mov VCPU_RBX(%_ASM_AX), %_ASM_BX
-	mov VCPU_RBP(%_ASM_AX), %_ASM_BP
-	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
-	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
+	mov VCPU_RAX(%_ASM_DI), %_ASM_AX
+	mov VCPU_RCX(%_ASM_DI), %_ASM_CX
+	mov VCPU_RDX(%_ASM_DI), %_ASM_DX
+	mov VCPU_RBX(%_ASM_DI), %_ASM_BX
+	mov VCPU_RBP(%_ASM_DI), %_ASM_BP
+	mov VCPU_RSI(%_ASM_DI), %_ASM_SI
 #ifdef CONFIG_X86_64
-	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
+	mov VCPU_R8 (%_ASM_DI),  %r8
+	mov VCPU_R9 (%_ASM_DI),  %r9
+	mov VCPU_R10(%_ASM_DI), %r10
+	mov VCPU_R11(%_ASM_DI), %r11
+	mov VCPU_R12(%_ASM_DI), %r12
+	mov VCPU_R13(%_ASM_DI), %r13
+	mov VCPU_R14(%_ASM_DI), %r14
+	mov VCPU_R15(%_ASM_DI), %r15
 #endif
-	/* Load guest RAX.  This kills the @vmx pointer! */
-	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
+	/* Load guest RDI.  This kills the @vmx pointer! */
+	mov VCPU_RDI(%_ASM_DI), %_ASM_DI
 
 	/* Check EFLAGS.ZF from 'testb' above */
 	jz .Lvmlaunch
-- 
2.31.1



  parent reply	other threads:[~2022-10-28 23:10 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-28 23:07 [RFC PATCH 0/7] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly Paolo Bonzini
2022-10-28 23:07 ` [PATCH 1/7] KVM: VMX: remove regs argument of __vmx_vcpu_run Paolo Bonzini
2022-10-31 17:37   ` Sean Christopherson
2022-11-01 17:32     ` Josh Poimboeuf
2022-11-01 18:03       ` Sean Christopherson
2022-11-02 17:42     ` Paolo Bonzini
2022-10-28 23:07 ` Paolo Bonzini [this message]
2022-10-28 23:07 ` [PATCH 3/7] KVM: SVM: extract VMCB accessors to a new file Paolo Bonzini
2022-10-28 23:07 ` [PATCH 4/7] KVM: SVM: replace argument of __svm_vcpu_run with vcpu_svm Paolo Bonzini
2022-10-29 22:10   ` kernel test robot
2022-10-28 23:07 ` [PATCH 5/7] KVM: SVM: adjust register allocation for __svm_vcpu_run Paolo Bonzini
2022-10-28 23:07 ` [PATCH 6/7] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly Paolo Bonzini
2022-10-30  8:36   ` kernel test robot
2022-11-02 15:28   ` Josh Poimboeuf
2022-11-02 16:02     ` Paolo Bonzini
2022-10-28 23:07 ` [PATCH 7/7] x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callers Paolo Bonzini

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