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17 Dec 2024 05:10:37 -0800 X-CSE-ConnectionGUID: glnTXi45RiaU01TPwBjpew== X-CSE-MsgGUID: RNq2sGcITpqbtNjk+X0dhg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,241,1728975600"; d="scan'208";a="98100974" Received: from lfiedoro-mobl.ger.corp.intel.com (HELO localhost) ([10.245.246.36]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Dec 2024 05:10:29 -0800 Date: Tue, 17 Dec 2024 15:10:23 +0200 From: Tony Lindgren To: Ira Weiny Cc: Xiaoyao Li , "Edgecombe, Rick P" , "riku.voipio@iki.fi" , "imammedo@redhat.com" , "Liu, Zhao1" , "marcel.apfelbaum@gmail.com" , "anisinha@redhat.com" , "mst@redhat.com" , "pbonzini@redhat.com" , "richard.henderson@linaro.org" , "armbru@redhat.com" , "philmd@linaro.org" , "cohuck@redhat.com" , "mtosatti@redhat.com" , "eblake@redhat.com" , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "wangyanan55@huawei.com" , "berrange@redhat.com" Subject: Re: [PATCH v6 09/60] i386/tdx: Initialize TDX before creating TD vcpus Message-ID: References: <20241105062408.3533704-1-xiaoyao.li@intel.com> <20241105062408.3533704-10-xiaoyao.li@intel.com> <1235bac6ffe7be6662839adb2630c1a97d1cc4c5.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Received-SPF: none client-ip=198.175.65.11; envelope-from=tony.lindgren@linux.intel.com; helo=mgamail.intel.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Tue, 17 Dec 2024 08:48:20 -0500 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Dec 12, 2024 at 11:24:03AM -0600, Ira Weiny wrote: > On Wed, Nov 06, 2024 at 07:13:56AM +0200, Tony Lindgren wrote: > > On Wed, Nov 06, 2024 at 10:01:04AM +0800, Xiaoyao Li wrote: > > > On 11/6/2024 4:51 AM, Edgecombe, Rick P wrote: > > > > +Tony > > > > > > > > On Tue, 2024-11-05 at 01:23 -0500, Xiaoyao Li wrote: > > > > > +int tdx_pre_create_vcpu(CPUState *cpu, Error **errp) > > > > > +{ > > > > > +    X86CPU *x86cpu = X86_CPU(cpu); > > > > > +    CPUX86State *env = &x86cpu->env; > > > > > +    g_autofree struct kvm_tdx_init_vm *init_vm = NULL; > > > > > +    int r = 0; > > > > > + > > > > > +    QEMU_LOCK_GUARD(&tdx_guest->lock); > > > > > +    if (tdx_guest->initialized) { > > > > > +        return r; > > > > > +    } > > > > > + > > > > > +    init_vm = g_malloc0(sizeof(struct kvm_tdx_init_vm) + > > > > > +                        sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES); > > > > > + > > > > > +    r = setup_td_xfam(x86cpu, errp); > > > > > +    if (r) { > > > > > +        return r; > > > > > +    } > > > > > + > > > > > +    init_vm->cpuid.nent = kvm_x86_build_cpuid(env, init_vm->cpuid.entries, 0); > > > > > +    tdx_filter_cpuid(&init_vm->cpuid); > > > > > + > > > > > +    init_vm->attributes = tdx_guest->attributes; > > > > > +    init_vm->xfam = tdx_guest->xfam; > > > > > + > > > > > +    do { > > > > > +        r = tdx_vm_ioctl(KVM_TDX_INIT_VM, 0, init_vm); > > > > > +    } while (r == -EAGAIN); > > > > > > > > KVM_TDX_INIT_VM can also return EBUSY. This should check for it, or KVM should > > > > standardize on one for both conditions. In KVM, both cases handle > > > > TDX_RND_NO_ENTROPY, but one tries to save some of the initialization for the > > > > next attempt. I don't know why userspace would need to differentiate between the > > > > two cases though, which makes me think we should just change the KVM side. > > > > > > I remember I tested retrying on the two cases and no surprise showed. > > > > > > I agree to change KVM side to return -EAGAIN for the two cases. > > > > OK yeah let's patch KVM for it. > > Will the patch to KVM converge such that it is ok for qemu to loop forever? Hmm I don't think we should loop forever anywhere, the retries needed should be only a few. Or what do you have in mind? Regards, Tony