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X-IronPort-AV: E=Sophos;i="5.82,325,1613433600"; d="scan'208";a="114312619" From: Siddharth Chandrasekaran To: Paolo Bonzini , Marcelo Tosatti CC: Siddharth Chandrasekaran , Siddharth Chandrasekaran , Alexander Graf , Evgeny Iakovlev , Liran Alon , Ioannis Aslanidis , , Subject: [PATCH 3/6] kvm/i386: Stop using cpu->kvm_msr_buf in kvm_put_one_msr() Date: Mon, 24 May 2021 21:54:06 +0200 Message-ID: <04c81a02c19a47e799e06b9c9ccb97e9a77f5927.1621885749.git.sidcha@amazon.de> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.43.161.253] X-ClientProxiedBy: EX13D10UWB004.ant.amazon.com (10.43.161.121) 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=52.95.49.90; envelope-from=prvs=771b08666=sidcha@amazon.de; helo=smtp-fw-6002.amazon.com X-Spam_score_int: -47 X-Spam_score: -4.8 X-Spam_bar: ---- X-Spam_report: (-4.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.371, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=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" kvm_put_one_msr() zeros cpu->kvm_msr_buf and uses it to set one MSR to KVM. It is pretty wasteful as cpu->kvm_msr_buf is 4096 bytes long; instead use a local buffer to avoid memset. Also, expose this method from kvm_i386.h as hyperv.c needs to set MSRs in a subsequent patch. Signed-off-by: Siddharth Chandrasekaran Reviewed-by: Alexander Graf --- target/i386/kvm/kvm.c | 12 ++++++++---- target/i386/kvm/kvm_i386.h | 1 + 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index d972eb4705..d19a2913fd 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2534,12 +2534,16 @@ static void kvm_msr_entry_add(X86CPU *cpu, uint32_t= index, uint64_t value) msrs->nmsrs++; } =20 -static int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value) +int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value) { - kvm_msr_buf_reset(cpu); - kvm_msr_entry_add(cpu, index, value); + uint8_t msr_buf[sizeof(struct kvm_msrs) + sizeof(struct kvm_msr_entry)= ] =3D { 0 }; + struct kvm_msrs *msr =3D (struct kvm_msrs *)msr_buf; + + msr->nmsrs =3D 1; + msr->entries[0].index =3D index; + msr->entries[0].data =3D value; =20 - return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf); + return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, msr); } =20 void kvm_put_apicbase(X86CPU *cpu, uint64_t value) diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h index dc72508389..0c4cd08071 100644 --- a/target/i386/kvm/kvm_i386.h +++ b/target/i386/kvm/kvm_i386.h @@ -40,6 +40,7 @@ void kvm_synchronize_all_tsc(void); void kvm_arch_reset_vcpu(X86CPU *cs); void kvm_arch_do_init_vcpu(X86CPU *cs); =20 +int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value); void kvm_put_apicbase(X86CPU *cpu, uint64_t value); =20 bool kvm_enable_x2apic(void); --=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