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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id 21sm1093214wmk.45.2022.01.25.10.29.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 25 Jan 2022 10:29:14 -0800 (PST) Subject: Re: [PATCH v4 06/21] KVM: arm64: Support SDEI_EVENT_CONTEXT hypercall To: Gavin Shan , kvmarm@lists.cs.columbia.edu Cc: maz@kernel.org, linux-kernel@vger.kernel.org, Jonathan.Cameron@huawei.com, pbonzini@redhat.com, will@kernel.org References: <20210815001352.81927-1-gshan@redhat.com> <20210815001352.81927-7-gshan@redhat.com> <28219c6a-5200-b8f3-09e1-6aa08565030a@redhat.com> From: Eric Auger Message-ID: <33a1ba7a-ad97-00db-a381-3dbc88835e15@redhat.com> Date: Tue, 25 Jan 2022 19:29:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <28219c6a-5200-b8f3-09e1-6aa08565030a@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gavin, On 1/12/22 3:33 AM, Gavin Shan wrote: > Hi Eric, > > On 11/10/21 7:16 PM, Eric Auger wrote: >> On 8/15/21 2:13 AM, Gavin Shan wrote: >>> This supports SDEI_EVENT_CONTEXT hypercall. It's used by the guest >>> to retrieved the original registers (R0 - R17) in its SDEI event >>> handler. Those registers can be corrupted during the SDEI event >>> delivery. >>> >>> Signed-off-by: Gavin Shan >>> --- >>>   arch/arm64/kvm/sdei.c | 40 ++++++++++++++++++++++++++++++++++++++++ >>>   1 file changed, 40 insertions(+) >>> >>> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c >>> index b022ce0a202b..b4162efda470 100644 >>> --- a/arch/arm64/kvm/sdei.c >>> +++ b/arch/arm64/kvm/sdei.c >>> @@ -270,6 +270,44 @@ static unsigned long >>> kvm_sdei_hypercall_enable(struct kvm_vcpu *vcpu, >>>       return ret; >>>   } >>>   +static unsigned long kvm_sdei_hypercall_context(struct kvm_vcpu >>> *vcpu) >>> +{ >>> +    struct kvm *kvm = vcpu->kvm; >>> +    struct kvm_sdei_kvm *ksdei = kvm->arch.sdei; >>> +    struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei; >>> +    struct kvm_sdei_vcpu_regs *regs; >>> +    unsigned long index = smccc_get_arg1(vcpu); >> s/index/param_id to match the spec? > > Sure, but "reg_id" seems better here. As the parameter indicates the GPR > index > to be fetched on request of the guest kernel. fine with me. > >>> +    unsigned long ret = SDEI_SUCCESS; >>> + >>> +    /* Sanity check */ >>> +    if (!(ksdei && vsdei)) { >>> +        ret = SDEI_NOT_SUPPORTED; >>> +        goto out; >>> +    } >>> + >>> +    if (index > ARRAY_SIZE(vsdei->state.critical_regs.regs)) { >>> +        ret = SDEI_INVALID_PARAMETERS; >>> +        goto out; >>> +    } >> I would move the above after regs = and use regs there (although the >> regs ARRAY_SIZE of both is identifical) > > Ok. > >>> + >>> +    /* Check if the pending event exists */ >>> +    spin_lock(&vsdei->lock); >>> +    if (!(vsdei->critical_event || vsdei->normal_event)) { >>> +        ret = SDEI_DENIED; >>> +        goto unlock; >>> +    } >>> + >>> +    /* Fetch the requested register */ >>> +    regs = vsdei->critical_event ? &vsdei->state.critical_regs : >>> +                       &vsdei->state.normal_regs; >>> +    ret = regs->regs[index]; >>> + >>> +unlock: >>> +    spin_unlock(&vsdei->lock); >>> +out: >>> +    return ret; >>> +} >>> + >>>   int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >>>   { >>>       u32 func = smccc_get_function(vcpu); >>> @@ -290,6 +328,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >>>           ret = kvm_sdei_hypercall_enable(vcpu, false); >>>           break; >>>       case SDEI_1_0_FN_SDEI_EVENT_CONTEXT: >>> +        ret = kvm_sdei_hypercall_context(vcpu); >>> +        break; >>>       case SDEI_1_0_FN_SDEI_EVENT_COMPLETE: >>>       case SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME: >>>       case SDEI_1_0_FN_SDEI_EVENT_UNREGISTER: >>> > > Thanks, > Gavin > Eric