From patchwork Thu Jul 2 10:57:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Roman Bolshakov X-Patchwork-Id: 11638691 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5A215912 for ; Thu, 2 Jul 2020 12:12:31 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2EF3320772 for ; Thu, 2 Jul 2020 12:12:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yadro.com header.i=@yadro.com header.b="rH3a77O5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2EF3320772 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yadro.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:44362 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqy4s-00046z-D5 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 02 Jul 2020 08:12:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42850) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqy4M-0003Zo-A3 for qemu-devel@nongnu.org; Thu, 02 Jul 2020 08:11:59 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:58872 helo=mta-01.yadro.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqy4J-0007yO-M3 for qemu-devel@nongnu.org; Thu, 02 Jul 2020 08:11:57 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id B49B34C8BA; Thu, 2 Jul 2020 12:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-transfer-encoding:content-type:content-type:mime-version :x-mailer:message-id:date:date:subject:subject:from:from :received:received:received; s=mta-01; t=1593691912; x= 1595506313; bh=QJGG3Mova4p9pA0I2cdvpCgyiFNW6vjsFYBqOxu+XRA=; b=r H3a77O53Kmf0uz0cWLu8ZAafPtLmQN2XNzdS+yVYRFGE7gJN/FSlVt4NWC41tNEl Hq8S9aj4wXSZ91fn4hW0oZK5JznzYQh9q7tf39q2MDR1mrNvWneGeU1b5R3ScyK6 9rzb7v6JpRuWULUepTP+p+iIlJmgFVOkAJ1n+jxOek= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fDMJUIAW0BQq; Thu, 2 Jul 2020 15:11:52 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id 826EB4C8B8; Thu, 2 Jul 2020 15:11:49 +0300 (MSK) Received: from localhost (172.17.204.212) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Thu, 2 Jul 2020 15:11:49 +0300 From: Roman Bolshakov To: Subject: [PATCH v3] i386: hvf: Implement CPU kick Date: Thu, 2 Jul 2020 13:57:23 +0300 Message-ID: <20200702105721.75333-1-r.bolshakov@yadro.com> X-Mailer: git-send-email 2.26.1 MIME-Version: 1.0 X-Originating-IP: [172.17.204.212] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Received-SPF: pass client-ip=89.207.88.252; envelope-from=r.bolshakov@yadro.com; helo=mta-01.yadro.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/02 08:11:53 X-ACL-Warn: Detected OS = Linux 3.11 and newer 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , Cameron Esfahani , Roman Bolshakov , Claudio Fontana , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" HVF doesn't have a CPU kick and without it it's not possible to perform an action on CPU thread until a VMEXIT happens. The kick is also needed for timely interrupt delivery. Existing implementation of CPU kick sends SIG_IPI (aka SIGUSR1) to vCPU thread, but it's different from what hv_vcpu_interrupt does. The latter one results in invocation of mp_cpus_kick() in XNU kernel [1]. mp_cpus_kick() sends an IPI through the host LAPIC to the HVF vCPU. And the kick interrupt leads to VM exit because "external-interrupt exiting” VM-execution control is enabled for HVF. hv_vcpu_interrupt() would have no effect if it's delivered when vCPU is outside of a guest, therefore to avoid kick loss it's complemented with a SIG_IPI handler and zero VMX-preemption timer. If the kick happens outside of hv_vcpu_run(), the signal handler will re-queue the kick by enabling zero VMX-preemption timer for the next hv_vcpu_run(). There's still a small chance of kick loss, on user-to-kernel border between atomic_mb_set's just before the entry to hv_vcpu_run and just after it. Also correct type of hvf_fd to the type of hv_vcpuid_t to avoid compilation warnings. 1. https://opensource.apple.com/source/xnu/xnu-6153.81.5/osfmk/i386/mp.c Cc: Cameron Esfahani Signed-off-by: Roman Bolshakov --- This is a rework of a kick patch in v2 of the series (https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg09899.html) based on the comments from Paolo. Unfortunately the race is still there, may be the race window is just a bit smaller. Changes since v2: - Reworked workaround to minimize kick loss race. Use signals to interrupt vCPU thread outside of hv_vcpu_run() and turn-on/turn-off VMX-preemeption timer, while timer value is always zero. v3 also assumes that VMX-preemption timer control is always available on the hardware that supports HVF. Changes since v1: - Reduced kick loss race (Paolo) and removed SIG_IPI blocking cpus.c | 13 +++++++---- include/hw/core/cpu.h | 2 +- include/sysemu/hvf.h | 1 + target/i386/cpu.h | 1 + target/i386/hvf/hvf.c | 53 ++++++++++++++++++++++++++++++++++++++++-- target/i386/hvf/vmcs.h | 1 + 6 files changed, 64 insertions(+), 7 deletions(-) diff --git a/cpus.c b/cpus.c index d94456ed29..6be42ff734 100644 --- a/cpus.c +++ b/cpus.c @@ -1792,10 +1792,15 @@ static void qemu_cpu_kick_thread(CPUState *cpu) return; } cpu->thread_kicked = true; - err = pthread_kill(cpu->thread->thread, SIG_IPI); - if (err && err != ESRCH) { - fprintf(stderr, "qemu:%s: %s", __func__, strerror(err)); - exit(1); + + if (hvf_enabled()) { + hvf_vcpu_kick(cpu); + } else { + err = pthread_kill(cpu->thread->thread, SIG_IPI); + if (err && err != ESRCH) { + fprintf(stderr, "qemu:%s: %s", __func__, strerror(err)); + exit(1); + } } #else /* _WIN32 */ if (!qemu_cpu_is_self(cpu)) { diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index b3f4b79318..288a2bd57e 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -438,7 +438,7 @@ struct CPUState { struct hax_vcpu_state *hax_vcpu; - int hvf_fd; + unsigned hvf_fd; /* track IOMMUs whose translations we've cached in the TCG TLB */ GArray *iommu_notifiers; diff --git a/include/sysemu/hvf.h b/include/sysemu/hvf.h index 6d3ee4fdb7..a1ab61403f 100644 --- a/include/sysemu/hvf.h +++ b/include/sysemu/hvf.h @@ -25,6 +25,7 @@ extern bool hvf_allowed; int hvf_init_vcpu(CPUState *); int hvf_vcpu_exec(CPUState *); +void hvf_vcpu_kick(CPUState *); void hvf_cpu_synchronize_state(CPUState *); void hvf_cpu_synchronize_post_reset(CPUState *); void hvf_cpu_synchronize_post_init(CPUState *); diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 7d77efd9e4..727c550c82 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1602,6 +1602,7 @@ typedef struct CPUX86State { struct kvm_nested_state *nested_state; #endif #if defined(CONFIG_HVF) + bool hvf_in_guest; HVFX86LazyFlags hvf_lflags; void *hvf_mmio_buf; #endif diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c index d81f569aed..6e9b212f37 100644 --- a/target/i386/hvf/hvf.c +++ b/target/i386/hvf/hvf.c @@ -73,6 +73,7 @@ #include "target/i386/cpu.h" HVFState *hvf_state; +pthread_key_t hvf_cpu; static void assert_hvf_ok(hv_return_t ret) { @@ -458,8 +459,17 @@ void hvf_vcpu_destroy(CPUState *cpu) assert_hvf_ok(ret); } -static void dummy_signal(int sig) +static void hvf_handle_ipi(int sig) { + CPUState *cpu = pthread_getspecific(hvf_cpu); + X86CPU *x86_cpu = X86_CPU(cpu); + CPUX86State *env = &x86_cpu->env; + + if (!atomic_xchg(&env->hvf_in_guest, false)) { + wvmcs(cpu->hvf_fd, VMCS_PIN_BASED_CTLS, + rvmcs(cpu->hvf_fd, VMCS_PIN_BASED_CTLS) + | VMCS_PIN_BASED_CTLS_VMX_PREEMPT_TIMER); + } } int hvf_init_vcpu(CPUState *cpu) @@ -474,16 +484,24 @@ int hvf_init_vcpu(CPUState *cpu) struct sigaction sigact; memset(&sigact, 0, sizeof(sigact)); - sigact.sa_handler = dummy_signal; + sigact.sa_handler = hvf_handle_ipi; sigaction(SIG_IPI, &sigact, NULL); + r = pthread_setspecific(hvf_cpu, cpu); + if (r) { + fprintf(stderr, "qemu:%s: %s", __func__, strerror(r)); + exit(1); + } + pthread_sigmask(SIG_BLOCK, NULL, &set); sigdelset(&set, SIG_IPI); + pthread_sigmask(SIG_SETMASK, &set, NULL); init_emu(); init_decoder(); hvf_state->hvf_caps = g_new0(struct hvf_vcpu_caps, 1); + env->hvf_in_guest = false; env->hvf_mmio_buf = g_new(char, 4096); r = hv_vcpu_create((hv_vcpuid_t *)&cpu->hvf_fd, HV_VCPU_DEFAULT); @@ -529,6 +547,7 @@ int hvf_init_vcpu(CPUState *cpu) wvmcs(cpu->hvf_fd, VMCS_EXCEPTION_BITMAP, 0); /* Double fault */ wvmcs(cpu->hvf_fd, VMCS_TPR_THRESHOLD, 0); + wvmcs(cpu->hvf_fd, VMCS_PREEMPTION_TIMER_VALUE, 0); x86cpu = X86_CPU(cpu); x86cpu->env.xsave_buf = qemu_memalign(4096, 4096); @@ -631,7 +650,9 @@ int hvf_vcpu_exec(CPUState *cpu) return EXCP_HLT; } + atomic_mb_set(&env->hvf_in_guest, true); hv_return_t r = hv_vcpu_run(cpu->hvf_fd); + atomic_mb_set(&env->hvf_in_guest, false); assert_hvf_ok(r); /* handle VMEXIT */ @@ -774,6 +795,10 @@ int hvf_vcpu_exec(CPUState *cpu) vmx_clear_nmi_window_exiting(cpu); ret = EXCP_INTERRUPT; break; + case EXIT_REASON_VMX_PREEMPT: + wvmcs(cpu->hvf_fd, VMCS_PIN_BASED_CTLS, + rvmcs(cpu->hvf_fd, VMCS_PIN_BASED_CTLS) + & ~VMCS_PIN_BASED_CTLS_VMX_PREEMPT_TIMER); case EXIT_REASON_EXT_INTR: /* force exit and allow io handling */ ret = EXCP_INTERRUPT; @@ -872,6 +897,22 @@ int hvf_vcpu_exec(CPUState *cpu) return ret; } +void hvf_vcpu_kick(CPUState *cpu) +{ + hv_return_t err; + + err = pthread_kill(cpu->thread->thread, SIG_IPI); + if (err) { + fprintf(stderr, "qemu:%s: %s", __func__, strerror(err)); + exit(1); + } + err = hv_vcpu_interrupt(&cpu->hvf_fd, 1); + if (err) { + fprintf(stderr, "qemu:%s error %#x\n", __func__, err); + exit(1); + } +} + bool hvf_allowed; static int hvf_accel_init(MachineState *ms) @@ -880,6 +921,14 @@ static int hvf_accel_init(MachineState *ms) hv_return_t ret; HVFState *s; + /* TODO add pthread_key_delete() */ + ret = pthread_key_create(&hvf_cpu, NULL); + if (ret) { + fprintf(stderr, "qemu:%s: %s", __func__, strerror(ret)); + exit(1); + } + + /* TODO add hv_vm_unmap() and hv_vm_destroy() */ ret = hv_vm_create(HV_VM_DEFAULT); assert_hvf_ok(ret); diff --git a/target/i386/hvf/vmcs.h b/target/i386/hvf/vmcs.h index 42de7ebc3a..6615365023 100644 --- a/target/i386/hvf/vmcs.h +++ b/target/i386/hvf/vmcs.h @@ -349,6 +349,7 @@ #define VMCS_PIN_BASED_CTLS_EXTINT (1 << 0) #define VMCS_PIN_BASED_CTLS_NMI (1 << 3) #define VMCS_PIN_BASED_CTLS_VNMI (1 << 5) +#define VMCS_PIN_BASED_CTLS_VMX_PREEMPT_TIMER (1 << 6) #define VMCS_PRI_PROC_BASED_CTLS_INT_WINDOW_EXITING (1 << 2) #define VMCS_PRI_PROC_BASED_CTLS_TSC_OFFSET (1 << 3)