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Subject[PATCH 1/7] KVM: VMX: Introduce generic fastpath handler
Date
From: Wanpeng Li <wanpengli@tencent.com>

Introduce generic fastpath handler to handle MSR fastpath, VMX-preemption
timer fastpath etc; move it after vmx_complete_interrupts() in order to
catch events delivered to the guest, and abort the fast path in later
patches. While at it, move the kvm_exit tracepoint so that it is printed
for fastpath vmexits as well.

There is no observed performance effect for the IPI fastpath after this patch.

Tested-by: Haiwei Li <lihaiwei@tencent.com>
Cc: Haiwei Li <lihaiwei@tencent.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <1588055009-12677-2-git-send-email-wanpengli@tencent.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx/vmx.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 13cdb8469848..ad57c4744b99 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5907,8 +5907,6 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
u32 exit_reason = vmx->exit_reason;
u32 vectoring_info = vmx->idt_vectoring_info;

- trace_kvm_exit(exit_reason, vcpu, KVM_ISA_VMX);
-
/*
* Flush logged GPAs PML buffer, this will make dirty_bitmap more
* updated. Another good is, in kvm_vm_ioctl_get_dirty_log, before
@@ -6604,6 +6602,16 @@ 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)
+{
+ switch (to_vmx(vcpu)->exit_reason) {
+ case EXIT_REASON_MSR_WRITE:
+ return handle_fastpath_set_msr_irqoff(vcpu);
+ default:
+ 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)
@@ -6778,17 +6786,18 @@ 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);

+ trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX);
+
+ if (is_guest_mode(vcpu))
+ return EXIT_FASTPATH_NONE;
+
+ exit_fastpath = vmx_exit_handlers_fastpath(vcpu);
return exit_fastpath;
}

--
2.18.2

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