From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 853093A7F45; Thu, 10 Sep 2026 10:21:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789035697; cv=none; b=fq7RDvi2+dg3WeskYoK28XmKosWsGXyirRZv2JHiyh2mvvq+fVKOq4yImaDf+/CGX8Rq0CsJD98LxttWvorDNanJEPWjWkzSp19rQpVDFQS85R2hqWQ4Ct0avsTJyBr3WbW/3MKotd3IHjmSq2qCyjTsZCIHdy3I2Qfvubtp128= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789035697; c=relaxed/simple; bh=NdJwICU4hKphndkhJfKo4meJGdIZvN650SafLlOB/BM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gEKFmEtlk1HFN8SIrdSA9kC/DopyPcymRnUAbOWzkTqJeoxWiacGjO+yAMX6JQ7fouoxrHaK7BhPBvxd/Z7255UZLtl+V4ooNs/nVwNm54ctUyF7FogWQ7DcPWPIBrUBS28f6LRaSL+WUNDes+FubZakNVp9divq7FWRXjOSd/E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=k//7Ud38; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="k//7Ud38" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 51C7D143D; Thu, 10 Sep 2026 03:21:31 -0700 (PDT) Received: from [10.0.129.245] (unknown [10.0.129.245]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 899BA3F7B4; Thu, 10 Sep 2026 03:21:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789035695; bh=NdJwICU4hKphndkhJfKo4meJGdIZvN650SafLlOB/BM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=k//7Ud38dQTnvnKQxVZAcd73FhyR9Iv9bKLlrmoT04DSSuniGXJGJi8nFSmCLEuE8 fX11Ow/pTfdIBC/fgh+DTGC9ZRproSkmFOyVb9rmmwngQfXyaH/MYJCYNZcxFenoQH YnDm/TS+rtBLyZhhM83WRgOUSjTOe3zhZn+o0zjo= Message-ID: Date: Thu, 10 Sep 2026 11:21:29 +0100 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v17 04/20] KVM: arm64: Refactor the vcpu_load to allow for VM specific callbacks Content-Language: en-GB To: Gavin Shan , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: maz@kernel.org, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com References: <20260908162223.1683432-1-suzuki.poulose@arm.com> <20260908162223.1683432-5-suzuki.poulose@arm.com> From: Suzuki K Poulose In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/09/2026 05:00, Gavin Shan wrote: > Hi Suzuki, > > On 9/9/26 2:22 AM, Suzuki K Poulose wrote: >> Based on a work by Marc Zyngier >> >> To keep the VCPU load/put handling cleaner with the different kinds of >> VM types, >> we are about to introduce VM specific callbacks to do just the right >> thing. >> In preparation for that, make some refactoring to add the change easier. >> >> No functional changes intended. >> >> Signed-off-by: Suzuki K Poulose >> --- >>   arch/arm64/kvm/arm.c | 46 +++++++++++++++++++++++++++----------------- >>   1 file changed, 28 insertions(+), 18 deletions(-) >> > > Nitpicks below, none of them are introduced by this patch itself. In > either way: > > Reviewed-by: Gavin Shan Thank you ! > >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c >> index 67f1ff9bc4fbe..51fc651267157 100644 >> --- a/arch/arm64/kvm/arm.c >> +++ b/arch/arm64/kvm/arm.c >> @@ -683,14 +683,11 @@ static bool kvm_vcpu_should_clear_twe(struct >> kvm_vcpu *vcpu) >>       return single_task_running(); >>   } >> -void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) >> +static void vcpu_prepare_mmu(struct kvm_vcpu *vcpu) >>   { >>       struct kvm_s2_mmu *mmu; >>       int *last_ran; >> -    if (is_protected_kvm_enabled()) >> -        goto nommu; >> - >>       if (vcpu_has_nv(vcpu)) >>           kvm_vcpu_load_hw_mmu(vcpu); >> @@ -720,10 +717,33 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, >> int cpu) >>           kvm_call_hyp(__kvm_flush_cpu_context, mmu); >>           *last_ran = vcpu->vcpu_idx; >>       } >> +} >> + >> +static void vcpu_set_wfx_traps(struct kvm_vcpu *vcpu) >> +{ >> +    if (kvm_vcpu_should_clear_twe(vcpu)) >> +        vcpu->arch.hcr_el2 &= ~HCR_TWE; >> +    else >> +        vcpu->arch.hcr_el2 |= HCR_TWE; >> + >> +    if (kvm_vcpu_should_clear_twi(vcpu)) >> +        vcpu->arch.hcr_el2 &= ~HCR_TWI; >> +    else >> +        vcpu->arch.hcr_el2 |= HCR_TWI; >> +} >> + > > It seems FIELD_MODIFY() can be applied here if no visible constraints > exist: > >     FIELD_MODIFY(HCR_TWE, vcpu->arch.hcr_el2, ! > kvm_vcpu_should_clear_twe(vcpu)); >     FIELD_MODIFY(HCR_TWI, vcpu->arch.hcr_el2, ! > kvm_vcpu_should_clear_twi(vcpu)); I would leave this out for now. Can be a separate patch > >> +static void vcpu_load_pvtime(struct kvm_vcpu *vcpu) >> +{ >> +    if (kvm_arm_is_pvtime_enabled(&vcpu->arch)) >> +        kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu); >> +} >> + >> +void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) >> +{ >> +    if (!is_protected_kvm_enabled()) >> +        vcpu_prepare_mmu(vcpu); >> > > I think we probably try to depend on kvm->arch.vm_flavor instead > of !is_protected_kvm_enabled(). > >     struct kvm *kvm = vcpu->kvm; > >     if (kvm_vm_is_protected(kvm) || kvm_vm_flavor_eq(kvm, VM_PKVM)) >         vcpu_prepare_mmu(vcpu); This will be removed as part of the call back in the next patch. Cheers Suzuki