Messages in this thread | | | Date | Wed, 22 Feb 2023 13:17:25 +0100 | From | Paolo Bonzini <> | Subject | Re: [PATCH v2 06/29] LoongArch: KVM: Implement vcpu create and destroy interface |
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On 2/22/23 02:52, Tianrui Zhao wrote: >> >>> + vcpu->arch.guest_eentry = (unsigned long)kvm_context->kvm_eentry; >>> + vcpu->arch.vcpu_run = kvm_context->kvm_enter_guest; >>> + vcpu->arch.handle_exit = _kvm_handle_exit; >> >> Here as well, whatever is constant must not be stored in struct >> kvm_arch_vcpu. >> >> Paolo > > Thanks, we use this in vcpu_arch because the vcpu_arch is used as > argument in switch.S' methods, we can quickly access the guest_eentry > and handle_exit by using the KVM_ARCH_GEENTRY, KVM_ARCH_HANDLE_EXIT > offsets. If we change to global variable , we should relocate it in > switch.S and may lead to lower accessing speed.
For guest_eentry and handle_exit this is correct so you can add a comment in kvm_host.h, like
/* Pointers stored here for easy access from assembly code. */
However, vcpu->arch.vcpu_run is not used in switch.S so there is no need to store it in struct kvm_arch_vcpu. Since you're already going to move kvm_enter_guest out of kvm_context and into a global variable, please give it the right pointer-to-function type instead of using unsigned long.
Paolo
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