linux-kernel - [PATCH v2 3/5] KVM: VMX: Introduce generic fastpath handler

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Date:   Thu, 23 Apr 2020 17:01:45 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Haiwei Li <lihaiwei@...cent.com>
Subject: [PATCH v2 3/5] KVM: VMX: Introduce generic fastpath handler

From: Wanpeng Li <wanpengli@...cent.com>

Introduce generic fastpath handler to handle MSR fastpath, VMX-preemption 
timer fastpath etc.

Tested-by: Haiwei Li <lihaiwei@...cent.com>
Cc: Haiwei Li <lihaiwei@...cent.com>
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/vmx/vmx.c          | 24 +++++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f809763..bcddf93 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -188,6 +188,7 @@ enum {
 enum exit_fastpath_completion {
 	EXIT_FASTPATH_NONE,
 	EXIT_FASTPATH_SKIP_EMUL_INS,
+	EXIT_FASTPATH_CONT_RUN,
 };
 
 struct x86_emulate_ctxt;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index fd20cb3..2613e58 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6569,6 +6569,20 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)
 	}
 }
 
+static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
+{
+	if (!is_guest_mode(vcpu)) {
+		switch (to_vmx(vcpu)->exit_reason) {
+		case EXIT_REASON_MSR_WRITE:
+			return handle_fastpath_set_msr_irqoff(vcpu);
+		default:
+			return EXIT_FASTPATH_NONE;
+		}
+	}
+
+	return EXIT_FASTPATH_NONE;
+}
+
 bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched);
 
 static enum exit_fastpath_completion vmx_vcpu_run(struct kvm_vcpu *vcpu)
@@ -6577,6 +6591,7 @@ static enum exit_fastpath_completion vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	unsigned long cr3, cr4;
 
+cont_run:
 	/* Record the guest's net vcpu time for enforced NMI injections. */
 	if (unlikely(!enable_vnmi &&
 		     vmx->loaded_vmcs->soft_vnmi_blocked))
@@ -6743,17 +6758,16 @@ static enum exit_fastpath_completion vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	if (unlikely(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
 		return EXIT_FASTPATH_NONE;
 
-	if (!is_guest_mode(vcpu) && vmx->exit_reason == EXIT_REASON_MSR_WRITE)
-		exit_fastpath = handle_fastpath_set_msr_irqoff(vcpu);
-	else
-		exit_fastpath = EXIT_FASTPATH_NONE;
-
 	vmx->loaded_vmcs->launched = 1;
 	vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 
 	vmx_recover_nmi_blocking(vmx);
 	vmx_complete_interrupts(vmx);
 
+	exit_fastpath = vmx_exit_handlers_fastpath(vcpu);
+	if (exit_fastpath == EXIT_FASTPATH_CONT_RUN)
+		goto cont_run;
+
 	return exit_fastpath;
 }
 
-- 
2.7.4