From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AF06C433E2 for ; Wed, 1 Jul 2020 16:29:59 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2C30B20781 for ; Wed, 1 Jul 2020 16:29:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="M+x48VXp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C30B20781 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37040 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqfcU-0000vN-9o for qemu-devel@archiver.kernel.org; Wed, 01 Jul 2020 12:29:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45484) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqfbQ-00086l-HK for qemu-devel@nongnu.org; Wed, 01 Jul 2020 12:28:52 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:24014 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jqfbN-0001VA-Ga for qemu-devel@nongnu.org; Wed, 01 Jul 2020 12:28:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593620927; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=w2n6LEEjIk2Z9OvOEn3yHX8Kz7EkJWFx8vtbVdWYn5Q=; b=M+x48VXpONmcE8xhFfSPBJagjFHrtg49PfwgPQUCZOGoi++HIHVsZ082iiECXLO4OrK+n/ kA4D9LQuzm2xDrLw/9ZMTiKbEmpnFjJ2VDBme3CG9WLQpXI8ifHaXjCQhDY8CV7TOAXPlK qMX6Lh+QINO1kWFpoe+/YKOfpBjnMME= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-373--CXtNdzgMKC0QMtKVhh-Ug-1; Wed, 01 Jul 2020 12:28:45 -0400 X-MC-Unique: -CXtNdzgMKC0QMtKVhh-Ug-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 04B2964AD0 for ; Wed, 1 Jul 2020 16:28:45 +0000 (UTC) Received: from work-vm (ovpn-114-200.ams2.redhat.com [10.36.114.200]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 31A6260CD1; Wed, 1 Jul 2020 16:28:44 +0000 (UTC) Date: Wed, 1 Jul 2020 17:28:41 +0100 From: "Dr. David Alan Gilbert" To: Paolo Bonzini Subject: Re: [PATCH] KVM: add support for AMD nested live migration Message-ID: <20200701162841.GG3608@work-vm> References: <20200624160608.383931-1-pbonzini@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200624160608.383931-1-pbonzini@redhat.com> User-Agent: Mutt/1.14.3 (2020-06-14) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/01 01:29:47 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Paolo Bonzini (pbonzini@redhat.com) wrote: > Support for nested guest live migration is part of Linux 5.8, add the > corresponding code to QEMU. The migration format consists of a few > flags, is an opaque 4k blob. > > The blob is in VMCB format (the control area represents the L1 VMCB > control fields, the save area represents the pre-vmentry state; KVM does > not use the host save area since the AMD manual allows that) but QEMU > does not really care about that. However, the flags need to be > copied to hflags/hflags2 and back. > > In addition, support for retrieving and setting the AMD nested virtualization > states allows the L1 guest to be reset while running a nested guest, but > a small bug in CPU reset needs to be fixed for that to work. > > Signed-off-by: Paolo Bonzini OK, I wont claim to follow the flag wrangling, but from a migration point of view this makes sense to me. One question below... > --- > target/i386/cpu.c | 1 + > target/i386/cpu.h | 5 +++++ > target/i386/kvm.c | 42 ++++++++++++++++++++++++++++++++++-------- > target/i386/machine.c | 30 +++++++++++++++++++++++++++++- > 4 files changed, 69 insertions(+), 9 deletions(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 36cbd3d027..f1cbac2fb5 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5987,6 +5987,7 @@ static void x86_cpu_reset(DeviceState *dev) > /* init to reset state */ > > env->hflags2 |= HF2_GIF_MASK; > + env->hflags &= ~HF_GUEST_MASK; > > cpu_x86_update_cr0(env, 0x60000010); > env->a20_mask = ~0x0; > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 7d77efd9e4..282f9ad35f 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -2118,6 +2118,11 @@ static inline bool cpu_has_vmx(CPUX86State *env) > return env->features[FEAT_1_ECX] & CPUID_EXT_VMX; > } > > +static inline bool cpu_has_svm(CPUX86State *env) > +{ > + return env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_SVM; > +} > + > /* > * In order for a vCPU to enter VMX operation it must have CR4.VMXE set. > * Since it was set, CR4.VMXE must remain set as long as vCPU is in > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index 6adbff3d74..2b6b7443d2 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -1840,16 +1840,18 @@ int kvm_arch_init_vcpu(CPUState *cs) > if (max_nested_state_len > 0) { > assert(max_nested_state_len >= offsetof(struct kvm_nested_state, data)); > > - if (cpu_has_vmx(env)) { > + if (cpu_has_vmx(env) || cpu_has_svm(env)) { > struct kvm_vmx_nested_state_hdr *vmx_hdr; > > env->nested_state = g_malloc0(max_nested_state_len); > env->nested_state->size = max_nested_state_len; > env->nested_state->format = KVM_STATE_NESTED_FORMAT_VMX; > > - vmx_hdr = &env->nested_state->hdr.vmx; > - vmx_hdr->vmxon_pa = -1ull; > - vmx_hdr->vmcs12_pa = -1ull; > + if (cpu_has_vmx(env)) { > + vmx_hdr = &env->nested_state->hdr.vmx; > + vmx_hdr->vmxon_pa = -1ull; > + vmx_hdr->vmcs12_pa = -1ull; > + } > } > } > > @@ -3873,6 +3875,20 @@ static int kvm_put_nested_state(X86CPU *cpu) > return 0; > } > > + /* > + * Copy flags that are affected by reset from env->hflags and env->hflags2. > + */ > + if (env->hflags & HF_GUEST_MASK) { > + env->nested_state->flags |= KVM_STATE_NESTED_GUEST_MODE; > + } else { > + env->nested_state->flags &= ~KVM_STATE_NESTED_GUEST_MODE; > + } > + if (env->hflags2 & HF2_GIF_MASK) { > + env->nested_state->flags |= KVM_STATE_NESTED_GIF_SET; > + } else { > + env->nested_state->flags &= ~KVM_STATE_NESTED_GIF_SET; > + } > + > assert(env->nested_state->size <= max_nested_state_len); > return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_NESTED_STATE, env->nested_state); > } > @@ -3901,11 +3917,19 @@ static int kvm_get_nested_state(X86CPU *cpu) > return ret; > } > > + /* > + * Copy flags that are affected by reset to env->hflags and env->hflags2. > + */ > if (env->nested_state->flags & KVM_STATE_NESTED_GUEST_MODE) { > env->hflags |= HF_GUEST_MASK; > } else { > env->hflags &= ~HF_GUEST_MASK; > } > + if (env->nested_state->flags & KVM_STATE_NESTED_GIF_SET) { > + env->hflags2 |= HF2_GIF_MASK; > + } else { > + env->hflags2 &= ~HF2_GIF_MASK; > + } > > return ret; > } > @@ -3917,6 +3941,12 @@ int kvm_arch_put_registers(CPUState *cpu, int level) > > assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu)); > > + /* must be before kvm_put_nested_state so that EFER.SVME is set */ > + ret = kvm_put_sregs(x86_cpu); > + if (ret < 0) { > + return ret; > + } > + > if (level >= KVM_PUT_RESET_STATE) { > ret = kvm_put_nested_state(x86_cpu); > if (ret < 0) { > @@ -3950,10 +3980,6 @@ int kvm_arch_put_registers(CPUState *cpu, int level) > if (ret < 0) { > return ret; > } > - ret = kvm_put_sregs(x86_cpu); > - if (ret < 0) { > - return ret; > - } > /* must be before kvm_put_msrs */ > ret = kvm_inject_mce_oldstyle(x86_cpu); > if (ret < 0) { > diff --git a/target/i386/machine.c b/target/i386/machine.c > index 0c96531a56..8684a247c1 100644 > --- a/target/i386/machine.c > +++ b/target/i386/machine.c > @@ -1071,13 +1071,40 @@ static const VMStateDescription vmstate_vmx_nested_state = { > } > }; > > +static bool svm_nested_state_needed(void *opaque) > +{ > + struct kvm_nested_state *nested_state = opaque; > + > + /* > + * HF2_GIF_MASK is relevant for non-guest mode but it is already > + * serialized via hflags2. > + */ > + return (nested_state->format == KVM_STATE_NESTED_FORMAT_SVM && > + nested_state->size > offsetof(struct kvm_nested_state, data)); How does this nested_state->size work? It looks like even if it's 1 byte into 'data' we transmit a whole KVM_STATE_NESTED_SVM_VMCB_SIZE. Dave > +} > + > +static const VMStateDescription vmstate_svm_nested_state = { > + .name = "cpu/kvm_nested_state/svm", > + .version_id = 1, > + .minimum_version_id = 1, > + .needed = svm_nested_state_needed, > + .fields = (VMStateField[]) { > + VMSTATE_U64(hdr.svm.vmcb_pa, struct kvm_nested_state), > + VMSTATE_UINT8_ARRAY(data.svm[0].vmcb12, > + struct kvm_nested_state, > + KVM_STATE_NESTED_SVM_VMCB_SIZE), > + VMSTATE_END_OF_LIST() > + } > +}; > + > static bool nested_state_needed(void *opaque) > { > X86CPU *cpu = opaque; > CPUX86State *env = &cpu->env; > > return (env->nested_state && > - vmx_nested_state_needed(env->nested_state)); > + (vmx_nested_state_needed(env->nested_state) || > + svm_nested_state_needed(env->nested_state))); > } > > static int nested_state_post_load(void *opaque, int version_id) > @@ -1139,6 +1166,7 @@ static const VMStateDescription vmstate_kvm_nested_state = { > }, > .subsections = (const VMStateDescription*[]) { > &vmstate_vmx_nested_state, > + &vmstate_svm_nested_state, > NULL > } > }; > -- > 2.26.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK