From patchwork Mon Aug 24 08:55:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joerg Roedel X-Patchwork-Id: 11732449 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 E084813B1 for ; Mon, 24 Aug 2020 09:03:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE1DB2087D for ; Mon, 24 Aug 2020 09:03:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730029AbgHXJCZ (ORCPT ); Mon, 24 Aug 2020 05:02:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730136AbgHXI4j (ORCPT ); Mon, 24 Aug 2020 04:56:39 -0400 Received: from theia.8bytes.org (8bytes.org [IPv6:2a01:238:4383:600:38bc:a715:4b6d:a889]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01383C061574; Mon, 24 Aug 2020 01:56:38 -0700 (PDT) Received: from cap.home.8bytes.org (p4ff2bb8d.dip0.t-ipconnect.de [79.242.187.141]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id B8674168A; Mon, 24 Aug 2020 10:56:30 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Cc: Joerg Roedel , Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v6 73/76] x86/sev-es: Support CPU offline/online Date: Mon, 24 Aug 2020 10:55:08 +0200 Message-Id: <20200824085511.7553-74-joro@8bytes.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200824085511.7553-1-joro@8bytes.org> References: <20200824085511.7553-1-joro@8bytes.org> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Joerg Roedel Add a play_dead handler when running under SEV-ES. This is needed because the hypervisor can't deliver an SIPI request to restart the AP. Instead the kernel has to issue a VMGEXIT to halt the VCPU until the hypervisor wakes it up again. Signed-off-by: Joerg Roedel Link: https://lore.kernel.org/r/20200724160336.5435-73-joro@8bytes.org --- arch/x86/include/uapi/asm/svm.h | 1 + arch/x86/kernel/sev-es.c | 64 +++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+) diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index a19ce9681ec2..20a05839dd9a 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h @@ -84,6 +84,7 @@ /* SEV-ES software-defined VMGEXIT events */ #define SVM_VMGEXIT_MMIO_READ 0x80000001 #define SVM_VMGEXIT_MMIO_WRITE 0x80000002 +#define SVM_VMGEXIT_AP_HLT_LOOP 0x80000004 #define SVM_VMGEXIT_AP_JUMP_TABLE 0x80000005 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1 diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 09a45ccd6c1d..597ebb73411f 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -29,6 +29,8 @@ #include #include #include +#include +#include #define DR7_RESET_VALUE 0x400 @@ -522,6 +524,66 @@ static bool __init sev_es_setup_ghcb(void) return true; } +#ifdef CONFIG_HOTPLUG_CPU +static void sev_es_ap_hlt_loop(void) +{ + struct ghcb_state state; + struct ghcb *ghcb; + + ghcb = sev_es_get_ghcb(&state); + + while (true) { + vc_ghcb_invalidate(ghcb); + ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP); + ghcb_set_sw_exit_info_1(ghcb, 0); + ghcb_set_sw_exit_info_2(ghcb, 0); + + sev_es_wr_ghcb_msr(__pa(ghcb)); + VMGEXIT(); + + /* Wakeup signal? */ + if (ghcb_sw_exit_info_2_is_valid(ghcb) && + ghcb->save.sw_exit_info_2) + break; + } + + sev_es_put_ghcb(&state); +} + +/* + * Play_dead handler when running under SEV-ES. This is needed because + * the hypervisor can't deliver an SIPI request to restart the AP. + * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the + * hypervisor wakes it up again. + */ +static void sev_es_play_dead(void) +{ + play_dead_common(); + + /* IRQs now disabled */ + + sev_es_ap_hlt_loop(); + + /* + * If we get here, the VCPU was woken up again. Jump to CPU + * startup code to get it back online. + */ + + start_cpu(); +} +#else /* CONFIG_HOTPLUG_CPU */ +#define sev_es_play_dead native_play_dead +#endif /* CONFIG_HOTPLUG_CPU */ + +#ifdef CONFIG_SMP +static void __init sev_es_setup_play_dead(void) +{ + smp_ops.play_dead = sev_es_play_dead; +} +#else +static inline void sev_es_setup_play_dead(void) { } +#endif + static void __init sev_es_alloc_runtime_data(int cpu) { struct sev_es_runtime_data *data; @@ -569,6 +631,8 @@ void __init sev_es_init_vc_handling(void) sev_es_init_ghcb(cpu); sev_es_setup_vc_stacks(cpu); } + + sev_es_setup_play_dead(); } static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt)