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X-IronPort-AV: E=Sophos;i="5.83,298,1616457600"; d="scan'208";a="8698652" From: Siddharth Chandrasekaran To: Paolo Bonzini , Marcelo Tosatti CC: Siddharth Chandrasekaran , Siddharth Chandrasekaran , Alexander Graf , Evgeny Iakovlev , Liran Alon , Ioannis Aslanidis , , Subject: [PATCH v2 5/6] kvm/i386: Add support for user space MSR filtering Date: Fri, 25 Jun 2021 12:23:30 +0200 Message-ID: <678fba871629cc645cfe5b95292327cd8ae3e61f.1624615713.git.sidcha@amazon.de> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.43.161.183] X-ClientProxiedBy: EX13D05UWC004.ant.amazon.com (10.43.162.223) To EX13D28EUC003.ant.amazon.com (10.43.164.43) Precedence: Bulk 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=99.78.197.217; envelope-from=prvs=8031d3708=sidcha@amazon.de; helo=smtp-fw-80006.amazon.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.362, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @amazon.de) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Check and enable user space MSR filtering capability and handle new exit reason KVM_EXIT_X86_WRMSR. This will be used in a follow up patch to implement hyper-v overlay pages. Signed-off-by: Siddharth Chandrasekaran --- target/i386/kvm/kvm.c | 67 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index bcf1b4f2d0..b89b343acc 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -117,6 +117,8 @@ static bool has_msr_ucode_rev; static bool has_msr_vmx_procbased_ctls2; static bool has_msr_perf_capabs; static bool has_msr_pkrs; +static bool has_msr_filtering; +static bool msr_filters_active; =20 static uint32_t has_architectural_pmu_version; static uint32_t num_architectural_pmu_gp_counters; @@ -2183,6 +2185,42 @@ static void register_smram_listener(Notifier *n, voi= d *unused) &smram_address_space, 1); } =20 +static void kvm_set_msr_filter_range(struct kvm_msr_filter_range *range, u= int32_t flags, + uint32_t base, uint32_t nmsrs, ...) +{ + int i, filter_to_userspace; + va_list ap; + + range->flags =3D flags; + range->nmsrs =3D nmsrs; + range->base =3D base; + + va_start(ap, nmsrs); + for (i =3D 0; i < nmsrs; i++) { + filter_to_userspace =3D va_arg(ap, int); + if (!filter_to_userspace) { + range->bitmap[i / 8] =3D 1 << (i % 8); + } + } + va_end(ap); +} + +static int kvm_set_msr_filters(KVMState *s) +{ + int r; + struct kvm_msr_filter filter =3D { }; + + filter.flags =3D KVM_MSR_FILTER_DEFAULT_ALLOW; + + r =3D kvm_vm_ioctl(s, KVM_X86_SET_MSR_FILTER, &filter); + if (r !=3D 0) { + error_report("kvm: failed to set MSR filters"); + return -1; + } + + return 0; +} + int kvm_arch_init(MachineState *ms, KVMState *s) { uint64_t identity_base =3D 0xfffbc000; @@ -2314,6 +2352,17 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } } =20 + has_msr_filtering =3D kvm_check_extension(s, KVM_CAP_X86_USER_SPACE_MS= R) && + kvm_check_extension(s, KVM_CAP_X86_MSR_FILTER); + if (has_msr_filtering) { + ret =3D kvm_vm_enable_cap(s, KVM_CAP_X86_USER_SPACE_MSR, 0, + KVM_MSR_EXIT_REASON_FILTER); + if (ret =3D=3D 0) { + ret =3D kvm_set_msr_filters(s); + msr_filters_active =3D (ret =3D=3D 0); + } + } + return 0; } =20 @@ -4587,6 +4636,18 @@ static bool host_supports_vmx(void) return ecx & CPUID_EXT_VMX; } =20 +static int kvm_handle_rdmsr(X86CPU *cpu, struct kvm_run *run) +{ + run->msr.error =3D 1; + return 0; +} + +static int kvm_handle_wrmsr(X86CPU *cpu, struct kvm_run *run) +{ + run->msr.error =3D 1; + return 0; +} + #define VMX_INVALID_GUEST_STATE 0x80000021 =20 int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run) @@ -4645,6 +4706,12 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_ru= n *run) ioapic_eoi_broadcast(run->eoi.vector); ret =3D 0; break; + case KVM_EXIT_X86_RDMSR: + ret =3D kvm_handle_rdmsr(cpu, run); + break; + case KVM_EXIT_X86_WRMSR: + ret =3D kvm_handle_wrmsr(cpu, run); + break; default: fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason); ret =3D -1; --=20 2.17.1 Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879