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Mon, 27 Feb 2023 09:55:58 -0800 (PST) Received: from avogadro.local ([2001:b07:6468:f312:9af8:e5f5:7516:fa89]) by smtp.gmail.com with ESMTPSA id e29-20020a170906749d00b008c33ebac259sm3450130ejl.127.2023.02.27.09.55.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Feb 2023 09:55:57 -0800 (PST) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: Xiaoyao Li Subject: [PULL 12/13] target/i386: KVM: allow fast string operations if host supports them Date: Mon, 27 Feb 2023 18:55:23 +0100 Message-Id: <20230227175524.710880-13-pbonzini@redhat.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230227175524.710880-1-pbonzini@redhat.com> References: <20230227175524.710880-1-pbonzini@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org These are just a flag that documents the performance characteristic of an instruction; it needs no hypervisor support. So include them even if KVM does not show them. In particular, FZRM/FSRS/FSRC have only been added very recently, but they are available on Sapphire Rapids processors. Reviewed-by: Xiaoyao Li Signed-off-by: Paolo Bonzini --- target/i386/kvm/kvm.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 587030199192..d18bd2f3e889 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -352,7 +352,7 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, { struct kvm_cpuid2 *cpuid; uint32_t ret = 0; - uint32_t cpuid_1_edx; + uint32_t cpuid_1_edx, unused; uint64_t bitmask; cpuid = get_supported_cpuid(s); @@ -399,10 +399,20 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, } else if (function == 6 && reg == R_EAX) { ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */ } else if (function == 7 && index == 0 && reg == R_EBX) { + /* Not new instructions, just an optimization. */ + uint32_t ebx; + host_cpuid(7, 0, &unused, &ebx, &unused, &unused); + ret |= ebx & CPUID_7_0_EBX_ERMS; + if (host_tsx_broken()) { ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE); } } else if (function == 7 && index == 0 && reg == R_EDX) { + /* Not new instructions, just an optimization. */ + uint32_t edx; + host_cpuid(7, 0, &unused, &unused, &unused, &edx); + ret |= edx & CPUID_7_0_EDX_FSRM; + /* * Linux v4.17-v4.20 incorrectly return ARCH_CAPABILITIES on SVM hosts. * We can detect the bug by checking if MSR_IA32_ARCH_CAPABILITIES is @@ -411,6 +421,11 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, if (!has_msr_arch_capabs) { ret &= ~CPUID_7_0_EDX_ARCH_CAPABILITIES; } + } else if (function == 7 && index == 1 && reg == R_EAX) { + /* Not new instructions, just an optimization. */ + uint32_t eax; + host_cpuid(7, 1, &eax, &unused, &unused, &unused); + ret |= eax & (CPUID_7_1_EAX_FZRM | CPUID_7_1_EAX_FSRS | CPUID_7_1_EAX_FSRC); } else if (function == 0xd && index == 0 && (reg == R_EAX || reg == R_EDX)) { /*