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03 Jun 2024 17:03:01 -0700 Received: from 9cc2c43eec6b.jf.intel.com ([10.54.77.100]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2024 17:03:01 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1717459386; x=1748995386; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=48VUZgnmiGXhvF6KdpwRb9P2+6jdiRU05eVhOiCgRk8=; b=TWB9VUckUavocwvQ0KVOll28h09ADWPq43dwOKq88Q3JheTJUMEREwPA AETVW181zFqEjyzuJ1WAfKGyj37+uNMIxjuBIP9X2wAr3lTb5J2xharnw qGIWLGNiKjQvd8Qi2/kKoCO7EVM2blnBQDTu9zgLiGS1W+ORnItzomBzz +Aau92yHt1Mx5sXZG4V0s9VHXJAg8JR7cVY0e1RIJptCwcad+Wx+oAJts hBukL7difka77KdnxFJXkicXrvQzBvCcXaLxhMb5bY4yCEKYsSmkwIOEm ygX7aJsn/vrHR2pnD9EN8hwmpJfyd5wNvTYtqTAvtWKbLqxHoICo2BwQV w==; X-CSE-ConnectionGUID: bFKmixXsR5aEajhgd/BC5w== X-CSE-MsgGUID: 7He7SkpuQGKYHxHFtgGKBw== X-IronPort-AV: E=McAfee;i="6600,9927,11092"; a="13924793" X-IronPort-AV: E=Sophos;i="6.08,212,1712646000"; d="scan'208";a="13924793" X-CSE-ConnectionGUID: XKeE7sPtRdee3vPKeCYNOg== X-CSE-MsgGUID: zTGuPn8VR8WoUZ4ePjdfEw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,212,1712646000"; d="scan'208";a="74529690" From: Zide Chen To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, mst@redhat.com, thuth@redhat.com, cfontana@suse.de, xiaoyao.li@intel.com, qemu-trivial@nongnu.org, seanjc@google.com, zhao1.liu@intel.com, Zide Chen Subject: [PATCH V3 2/2] target/i386: Advertise MWAIT iff host supports Date: Mon, 3 Jun 2024 17:02:22 -0700 Message-Id: <20240604000222.75065-3-zide.chen@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240604000222.75065-1-zide.chen@intel.com> References: <20240604000222.75065-1-zide.chen@intel.com> MIME-Version: 1.0 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=198.175.65.21; envelope-from=zide.chen@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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_MED=-2.3, 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1717459462827100003 Content-Type: text/plain; charset="utf-8" host_cpu_realizefn() sets CPUID_EXT_MONITOR without consulting host/KVM capabilities. This may cause problems: - If MWAIT/MONITOR is not available on the host, advertising this feature to the guest and executing MWAIT/MONITOR from the guest triggers #UD and the guest doesn't boot. This is because typically #UD takes priority over VM-Exit interception checks and KVM doesn't emulate MONITOR/MWAIT on #UD. - If KVM doesn't support KVM_X86_DISABLE_EXITS_MWAIT, MWAIT/MONITOR from the guest are intercepted by KVM, which is not what cpu-pm=3Don intends to do. In these cases, MWAIT/MONITOR should not be exposed to the guest. The logic in kvm_arch_get_supported_cpuid() to handle CPUID_EXT_MONITOR is correct and sufficient, and we can't set CPUID_EXT_MONITOR after x86_cpu_filter_features(). This was not an issue before commit 662175b91ff ("i386: reorder call to cpu_exec_realizefn") because the feature added in the accel-specific realizefn could be checked against host availability and filtered out. Additionally, it seems not a good idea to handle guest CPUID leaves in host_cpu_realizefn(), and this patch merges host_cpu_enable_cpu_pm() into kvm_cpu_realizefn(). Fixes: f5cc5a5c1686 ("i386: split cpu accelerators from cpu.c, using AccelC= PUClass") Fixes: 662175b91ff2 ("i386: reorder call to cpu_exec_realizefn") Signed-off-by: Zide Chen Reviewed-by: Igor Mammedov Reviewed-by: Xiaoyao Li Reviewed-by: Zhao Liu --- V3: - don't set CPUID_EXT_MONITOR in kvm_cpu_realizefn(). - Change title to reflect the main purpose of this patch. target/i386/host-cpu.c | 12 ------------ target/i386/kvm/kvm-cpu.c | 11 +++++++++-- 2 files changed, 9 insertions(+), 14 deletions(-) diff --git a/target/i386/host-cpu.c b/target/i386/host-cpu.c index 280e427c017c..8b8bf5afeccf 100644 --- a/target/i386/host-cpu.c +++ b/target/i386/host-cpu.c @@ -42,15 +42,6 @@ static uint32_t host_cpu_phys_bits(void) return host_phys_bits; } =20 -static void host_cpu_enable_cpu_pm(X86CPU *cpu) -{ - CPUX86State *env =3D &cpu->env; - - host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, - &cpu->mwait.ecx, &cpu->mwait.edx); - env->features[FEAT_1_ECX] |=3D CPUID_EXT_MONITOR; -} - static uint32_t host_cpu_adjust_phys_bits(X86CPU *cpu) { uint32_t host_phys_bits =3D host_cpu_phys_bits(); @@ -83,9 +74,6 @@ bool host_cpu_realizefn(CPUState *cs, Error **errp) X86CPU *cpu =3D X86_CPU(cs); CPUX86State *env =3D &cpu->env; =20 - if (cpu->max_features && enable_cpu_pm) { - host_cpu_enable_cpu_pm(cpu); - } if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) { uint32_t phys_bits =3D host_cpu_adjust_phys_bits(cpu); =20 diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c index f76972e47e61..148d10ce3711 100644 --- a/target/i386/kvm/kvm-cpu.c +++ b/target/i386/kvm/kvm-cpu.c @@ -65,8 +65,15 @@ static bool kvm_cpu_realizefn(CPUState *cs, Error **errp) * cpu_common_realizefn() (via xcc->parent_realize) */ if (cpu->max_features) { - if (enable_cpu_pm && kvm_has_waitpkg()) { - env->features[FEAT_7_0_ECX] |=3D CPUID_7_0_ECX_WAITPKG; + if (enable_cpu_pm) { + if (kvm_has_waitpkg()) { + env->features[FEAT_7_0_ECX] |=3D CPUID_7_0_ECX_WAITPKG; + } + + if (env->features[FEAT_1_ECX] & CPUID_EXT_MONITOR) { + host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, + &cpu->mwait.ecx, &cpu->mwait.edx); + } } if (cpu->ucode_rev =3D=3D 0) { cpu->ucode_rev =3D --=20 2.34.1