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bh=SmpDfYFECKgXbNmrxUMUhDB4r9v7TgPbNQQGtHlEzsY=; b=gAmE2yzy+HL4YAixWhBaNG3Efz1T+pC/hhYevi4A+5SFaqsovd9MYAQ4oocEeUY1ft+eyW 4onJ33MaONCxVXTIQCaQJ5iTkfxuC/f6Ecp6AOT19O/owglYw+zZVag5fx9bwc/dIZzaxg Iza98hZVWalRKdfW8fIqCRgfflOe1sw= X-MC-Unique: KWGwht4sMwynWwNULMOglg-1 From: Vitaly Kuznetsov To: qemu-devel@nongnu.org Subject: [PATCH v6 17/19] i386: HV_HYPERCALL_AVAILABLE privilege bit is always needed Date: Thu, 22 Apr 2021 18:11:28 +0200 Message-Id: <20210422161130.652779-18-vkuznets@redhat.com> In-Reply-To: <20210422161130.652779-1-vkuznets@redhat.com> References: <20210422161130.652779-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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=170.10.133.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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 autolearn=ham autolearn_force=no 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: Paolo Bonzini , Marcelo Tosatti , Eduardo Habkost , Igor Mammedov Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" According to TLFS, Hyper-V guest is supposed to check HV_HYPERCALL_AVAILABLE privilege bit before accessing HV_X64_MSR_GUEST_OS_ID/HV_X64_MSR_HYPERCALL MSRs but at least some Windows versions ignore that. As KVM is very permissive and allows accessing these MSRs unconditionally, no issue is observed. We may, however, want to tighten the checks eventually. Conforming to the spec is probably also a good idea. Add HV_HYPERCALL_AVAILABLE to all 'leaf' features with no dependencies. Signed-off-by: Vitaly Kuznetsov --- target/i386/kvm/kvm.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 2c1a77f9b00f..d81451276cd8 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -835,6 +835,8 @@ static struct { [HYPERV_FEAT_CRASH] =3D { .desc =3D "crash MSRs (hv-crash)", .flags =3D { + {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, + .bits =3D HV_HYPERCALL_AVAILABLE}, {.func =3D HV_CPUID_FEATURES, .reg =3D R_EDX, .bits =3D HV_GUEST_CRASH_MSR_AVAILABLE} } @@ -843,28 +845,28 @@ static struct { .desc =3D "reset MSR (hv-reset)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_RESET_AVAILABLE} + .bits =3D HV_HYPERCALL_AVAILABLE | HV_RESET_AVAILABLE} } }, [HYPERV_FEAT_VPINDEX] =3D { .desc =3D "VP_INDEX MSR (hv-vpindex)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_VP_INDEX_AVAILABLE} + .bits =3D HV_HYPERCALL_AVAILABLE | HV_VP_INDEX_AVAILABLE} } }, [HYPERV_FEAT_RUNTIME] =3D { .desc =3D "VP_RUNTIME MSR (hv-runtime)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_VP_RUNTIME_AVAILABLE} + .bits =3D HV_HYPERCALL_AVAILABLE | HV_VP_RUNTIME_AVAILABLE} } }, [HYPERV_FEAT_SYNIC] =3D { .desc =3D "synthetic interrupt controller (hv-synic)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_SYNIC_AVAILABLE} + .bits =3D HV_HYPERCALL_AVAILABLE | HV_SYNIC_AVAILABLE} } }, [HYPERV_FEAT_STIMER] =3D { @@ -879,7 +881,7 @@ static struct { .desc =3D "frequency MSRs (hv-frequencies)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_ACCESS_FREQUENCY_MSRS}, + .bits =3D HV_HYPERCALL_AVAILABLE | HV_ACCESS_FREQUENCY_MSRS}, {.func =3D HV_CPUID_FEATURES, .reg =3D R_EDX, .bits =3D HV_FREQUENCY_MSRS_AVAILABLE} } @@ -888,7 +890,8 @@ static struct { .desc =3D "reenlightenment MSRs (hv-reenlightenment)", .flags =3D { {.func =3D HV_CPUID_FEATURES, .reg =3D R_EAX, - .bits =3D HV_ACCESS_REENLIGHTENMENTS_CONTROL} + .bits =3D HV_HYPERCALL_AVAILABLE | + HV_ACCESS_REENLIGHTENMENTS_CONTROL} } }, [HYPERV_FEAT_TLBFLUSH] =3D { --=20 2.30.2