From patchwork Sun Jun 30 16:53:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13717234 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 310F8C27C4F for ; Sun, 30 Jun 2024 16:55:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sNxoG-0005da-Lc; Sun, 30 Jun 2024 12:53:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sNxoC-0005cG-Uc; Sun, 30 Jun 2024 12:53:48 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sNxoB-0005Iz-5b; Sun, 30 Jun 2024 12:53:48 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 7E74475761; Sun, 30 Jun 2024 19:53:20 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 47D8CFAD5E; Sun, 30 Jun 2024 19:53:27 +0300 (MSK) Received: (nullmailer pid 38212 invoked by uid 1000); Sun, 30 Jun 2024 16:53:27 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: Zide Chen , qemu-trivial@nongnu.org, Michael Tokarev Subject: [PULL 04/16] target/i386: Advertise MWAIT iff host supports Date: Sun, 30 Jun 2024 19:53:14 +0300 Message-Id: <20240630165327.38153-5-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240630165327.38153-1-mjt@tls.msk.ru> References: <20240630165327.38153-1-mjt@tls.msk.ru> MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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 From: Zide Chen 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=on 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 AccelCPUClass") Fixes: 662175b91ff2 ("i386: reorder call to cpu_exec_realizefn") Signed-off-by: Zide Chen Reviewed-by: Zhao Liu Reviewed-by: Xiaoyao Li Reviewed-by: Igor Mammedov Reviewed-by: Michael Tokarev Signed-off-by: Michael Tokarev --- 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 280e427c01..8b8bf5afec 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; } -static void host_cpu_enable_cpu_pm(X86CPU *cpu) -{ - CPUX86State *env = &cpu->env; - - host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, - &cpu->mwait.ecx, &cpu->mwait.edx); - env->features[FEAT_1_ECX] |= CPUID_EXT_MONITOR; -} - static uint32_t host_cpu_adjust_phys_bits(X86CPU *cpu) { uint32_t host_phys_bits = host_cpu_phys_bits(); @@ -83,9 +74,6 @@ bool host_cpu_realizefn(CPUState *cs, Error **errp) X86CPU *cpu = X86_CPU(cs); CPUX86State *env = &cpu->env; - 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 = host_cpu_adjust_phys_bits(cpu); diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c index f9b99b5f50..d57a68a301 100644 --- a/target/i386/kvm/kvm-cpu.c +++ b/target/i386/kvm/kvm-cpu.c @@ -64,8 +64,15 @@ 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] |= CPUID_7_0_ECX_WAITPKG; + if (enable_cpu_pm) { + if (kvm_has_waitpkg()) { + env->features[FEAT_7_0_ECX] |= 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 == 0) { cpu->ucode_rev =