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bh=uLuffatAT8VSGsl2+sdu35TWMeCNnPWh8yPZZ6BNRf4=; b=Dd7ufM5eTYsJiW6RRX88TvvTyNly2boEwiOlWWlHxpetpSuEjfO0/fiiSbx02FiV0V/C5j o8ArBN6VZ/wb8qM4pWZIsrfIYIz8ULmY3ZFikC6muK3Z9MR/YhRSap52B2p37qAdCMXRjr GdvJlp9vYr2KMgthd2jd5FGlFFQY9pM= X-MC-Unique: l3ezPl0zPHyXgmeG57Hb7w-1 From: Vitaly Kuznetsov To: qemu-devel@nongnu.org, Paolo Bonzini Subject: [PATCH v3 2/5] i386: Hyper-V Enlightened MSR bitmap feature Date: Tue, 19 Apr 2022 16:48:00 +0200 Message-Id: <20220419144803.1698337-3-vkuznets@redhat.com> In-Reply-To: <20220419144803.1698337-1-vkuznets@redhat.com> References: <20220419144803.1698337-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vkuznets@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action 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: , Cc: Marcelo Tosatti Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1650382386767100001 Content-Type: text/plain; charset="utf-8" The newly introduced enlightenment allow L0 (KVM) and L1 (Hyper-V) hypervisors to collaborate to avoid unnecessary updates to L2 MSR-Bitmap upon vmexits. Signed-off-by: Vitaly Kuznetsov --- docs/hyperv.txt | 10 ++++++++++ target/i386/cpu.c | 2 ++ target/i386/cpu.h | 1 + target/i386/kvm/hyperv-proto.h | 5 +++++ target/i386/kvm/kvm.c | 7 +++++++ 5 files changed, 25 insertions(+) diff --git a/docs/hyperv.txt b/docs/hyperv.txt index 0417c183a3b0..08429124a634 100644 --- a/docs/hyperv.txt +++ b/docs/hyperv.txt @@ -225,6 +225,16 @@ default (WS2016). Note: hv-version-id-* are not enlightenments and thus don't enable Hyper-V identification when specified without any other enlightenments. =20 +3.21. hv-emsr-bitmap +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +The enlightenment is nested specific, it targets Hyper-V on KVM guests. Wh= en +enabled, it allows L0 (KVM) and L1 (Hyper-V) hypervisors to collaborate to +avoid unnecessary updates to L2 MSR-Bitmap upon vmexits. While the protoco= l is +supported for both VMX (Intel) and SVM (AMD), the VMX implementation requi= res +Enlightened VMCS ('hv-evmcs') feature to also be enabled. + +Recommended: hv-evmcs (Intel) + 4. Supplementary features =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D =20 diff --git a/target/i386/cpu.c b/target/i386/cpu.c index cb6b5467d067..3f053919685f 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -6925,6 +6925,8 @@ static Property x86_cpu_properties[] =3D { HYPERV_FEAT_STIMER_DIRECT, 0), DEFINE_PROP_BIT64("hv-avic", X86CPU, hyperv_features, HYPERV_FEAT_AVIC, 0), + DEFINE_PROP_BIT64("hv-emsr-bitmap", X86CPU, hyperv_features, + HYPERV_FEAT_MSR_BITMAP, 0), DEFINE_PROP_ON_OFF_AUTO("hv-no-nonarch-coresharing", X86CPU, hyperv_no_nonarch_cs, ON_OFF_AUTO_OFF), DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false), diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 73dc387c52f5..9615c330315f 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1084,6 +1084,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWo= rd w, #define HYPERV_FEAT_IPI 13 #define HYPERV_FEAT_STIMER_DIRECT 14 #define HYPERV_FEAT_AVIC 15 +#define HYPERV_FEAT_MSR_BITMAP 16 =20 #ifndef HYPERV_SPINLOCK_NEVER_NOTIFY #define HYPERV_SPINLOCK_NEVER_NOTIFY 0xFFFFFFFF diff --git a/target/i386/kvm/hyperv-proto.h b/target/i386/kvm/hyperv-proto.h index 89f81afda7c6..38e25468122d 100644 --- a/target/i386/kvm/hyperv-proto.h +++ b/target/i386/kvm/hyperv-proto.h @@ -72,6 +72,11 @@ #define HV_ENLIGHTENED_VMCS_RECOMMENDED (1u << 14) #define HV_NO_NONARCH_CORESHARING (1u << 18) =20 +/* + * HV_CPUID_NESTED_FEATURES.EAX bits + */ +#define HV_NESTED_MSR_BITMAP (1u << 19) + /* * Basic virtualized MSRs */ diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index ff79994faa87..4059b46b9449 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -966,6 +966,13 @@ static struct { .bits =3D HV_DEPRECATING_AEOI_RECOMMENDED} } }, + [HYPERV_FEAT_MSR_BITMAP] =3D { + .desc =3D "enlightened MSR-Bitmap (hv-emsr-bitmap)", + .flags =3D { + {.func =3D HV_CPUID_NESTED_FEATURES, .reg =3D R_EAX, + .bits =3D HV_NESTED_MSR_BITMAP} + } + }, }; =20 static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max, --=20 2.35.1