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Mon, 14 Dec 2020 11:30:22 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0BEBPGkx139905; Mon, 14 Dec 2020 11:30:21 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 35d7ekbmx9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 14 Dec 2020 11:30:21 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0BEBUKKm019935; Mon, 14 Dec 2020 11:30:20 GMT Received: from [10.175.173.239] (/10.175.173.239) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 14 Dec 2020 03:30:20 -0800 Subject: Re: [PATCH v3 08/17] KVM: x86/xen: register shared_info page From: Joao Martins To: David Woodhouse Cc: Paolo Bonzini , Ankur Arora , Boris Ostrovsky , Sean Christopherson , graf@amazon.com, iaslan@amazon.de, pdurrant@amazon.com, aagch@amazon.com, fandree@amazon.com, kvm@vger.kernel.org References: <20201214083905.2017260-1-dwmw2@infradead.org> <20201214083905.2017260-9-dwmw2@infradead.org> Message-ID: Date: Mon, 14 Dec 2020 11:30:16 +0000 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9834 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 spamscore=0 bulkscore=0 suspectscore=0 adultscore=0 mlxscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012140081 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9834 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 mlxscore=0 suspectscore=0 adultscore=0 phishscore=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 clxscore=1015 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012140081 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 12/14/20 10:45 AM, Joao Martins wrote: > On 12/14/20 8:38 AM, David Woodhouse wrote: >> From: Joao Martins >> >> We add a new ioctl, XEN_HVM_SHARED_INFO, to allow hypervisor >> to know where the guest's shared info page is. >> >> Signed-off-by: Joao Martins >> Signed-off-by: David Woodhouse >> --- >> arch/x86/include/asm/kvm_host.h | 2 ++ >> arch/x86/kvm/xen.c | 27 +++++++++++++++++++++++++++ >> arch/x86/kvm/xen.h | 1 - >> include/uapi/linux/kvm.h | 4 ++++ >> 4 files changed, 33 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index c9a4feaee2e7..8bcd83dacf43 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -893,6 +893,8 @@ struct msr_bitmap_range { >> /* Xen emulation context */ >> struct kvm_xen { >> bool long_mode; >> + bool shinfo_set; >> + struct gfn_to_hva_cache shinfo_cache; >> }; >> >> enum kvm_irqchip_mode { >> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c >> index 52cb9e465542..9dd9c42842b8 100644 >> --- a/arch/x86/kvm/xen.c >> +++ b/arch/x86/kvm/xen.c >> @@ -13,9 +13,23 @@ >> #include >> >> #include >> +#include >> >> #include "trace.h" >> >> +static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn) >> +{ >> + int ret; >> + >> + ret = kvm_gfn_to_hva_cache_init(kvm, &kvm->arch.xen.shinfo_cache, >> + gfn_to_gpa(gfn), PAGE_SIZE); >> + if (ret) >> + return ret; >> + >> + kvm->arch.xen.shinfo_set = true; > > Can't you just use: > > kvm->arch.xen.shinfo_cache.gpa > > Rather than added a bool just to say you set a shinfo? > Or maybe @len in case you want to consider @gpa = 0 as valid. >> + return 0; >> +} > > And then here you just return @ret while removing the other conditional. > >> + >> int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) >> { >> int r = -ENOENT; >> @@ -28,6 +42,11 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) >> kvm->arch.xen.long_mode = !!data->u.long_mode; >> r = 0; >> break; >> + >> + case KVM_XEN_ATTR_TYPE_SHARED_INFO: >> + r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn); >> + break; >> + >> default: >> break; >> } >> @@ -44,6 +63,14 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) >> data->u.long_mode = kvm->arch.xen.long_mode; >> r = 0; >> break; >> + >> + case KVM_XEN_ATTR_TYPE_SHARED_INFO: >> + if (kvm->arch.xen.shinfo_set) { >> + data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa); >> + r = 0; >> + } >> + break; >> + >> default: >> break; >> } >> diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h >> index cd3c52b62068..120b7450252a 100644 >> --- a/arch/x86/kvm/xen.h >> +++ b/arch/x86/kvm/xen.h >> @@ -13,7 +13,6 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data); >> int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data); >> int kvm_xen_hypercall(struct kvm_vcpu *vcpu); >> int kvm_xen_hvm_config(struct kvm_vcpu *vcpu, u64 data); >> -void kvm_xen_destroy_vm(struct kvm *kvm); >> > spurious deletion ? > >> static inline bool kvm_xen_hypercall_enabled(struct kvm *kvm) >> { >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 6b556ef98b76..caa9faf3c5ad 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -1585,11 +1585,15 @@ struct kvm_xen_hvm_attr { >> >> union { >> __u8 long_mode; >> + struct { >> + __u64 gfn; >> + } shared_info; >> __u64 pad[4]; >> } u; >> }; >> >> #define KVM_XEN_ATTR_TYPE_LONG_MODE 0x0 >> +#define KVM_XEN_ATTR_TYPE_SHARED_INFO 0x1 >> >> /* Secure Encrypted Virtualization command */ >> enum sev_cmd_id { >>