linux-kernel - Re: [PATCH 1/4] KVM: x86: hyper-v: Drop redundant 'ex' parameter from kvm_hv_send

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Date:   Fri, 25 Feb 2022 20:21:13 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] KVM: x86: hyper-v: Drop redundant 'ex' parameter
 from kvm_hv_send_ipi()

On Tue, 2022-02-22 at 16:46 +0100, Vitaly Kuznetsov wrote:
> 'struct kvm_hv_hcall' has all the required information already,
> there's no need to pass 'ex' additionally.
> 
> No functional change intended.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> ---
>  arch/x86/kvm/hyperv.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 6e38a7d22e97..15b6a7bd2346 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -1875,7 +1875,7 @@ static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector,
>  	}
>  }
>  
> -static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool ex)
> +static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
>  {
>  	struct kvm *kvm = vcpu->kvm;
>  	struct hv_send_ipi_ex send_ipi_ex;
> @@ -1889,7 +1889,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool
>  	u32 vector;
>  	bool all_cpus;
>  
> -	if (!ex) {
> +	if (hc->code == HVCALL_SEND_IPI) {

I am thinking, if we already touch this code,
why not to use switch here instead on the hc->code,
so that we can catch this function being called with something else than
HVCALL_SEND_IPI_EX

>  		if (!hc->fast) {
>  			if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi,
>  						    sizeof(send_ipi))))
> @@ -2279,14 +2279,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
>  			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
>  			break;
>  		}
> -		ret = kvm_hv_send_ipi(vcpu, &hc, false);
> +		ret = kvm_hv_send_ipi(vcpu, &hc);
>  		break;
>  	case HVCALL_SEND_IPI_EX:
>  		if (unlikely(hc.fast || hc.rep)) {
>  			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
>  			break;
>  		}
> -		ret = kvm_hv_send_ipi(vcpu, &hc, true);
> +		ret = kvm_hv_send_ipi(vcpu, &hc);
>  		break;
>  	case HVCALL_POST_DEBUG_DATA:
>  	case HVCALL_RETRIEVE_DEBUG_DATA:



Other than this minor nitpick:

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>


Best regards,
	Maxim Levitsky